Document:

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                                                                     Exhibit 4.4

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                                  $500,000,000
                 2 1/4% CONVERTIBLE SUBORDINATED NOTES DUE 2006
                         REGISTRATION RIGHTS AGREEMENT

                         Dated as of December 11, 2001

                                  by and among

                             INVITROGEN CORPORATION

                                      and

                     CREDIT SUISSE FIRST BOSTON CORPORATION
                                UBS WARBURG LLC

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     This Registration Rights Agreement (this "AGREEMENT") is made and entered
into as of December 11, 2001 by and among Invitrogen Corporation, a Delaware
corporation (the "COMPANY"), and Credit Suisse First Boston Corporation and UBS
Warburg LLC (each an "INITIAL PURCHASER" and collectively, the "INITIAL
PURCHASERS"). The Company proposes to issue and sell to the Initial Purchasers
(the "INITIAL PLACEMENT") $500,000,000 in aggregate principal amount of its 2
1/4% Convertible Subordinated Notes due 2006 (the "FIRM CONVERTIBLE NOTES"). The
Company also proposes to issue and sell to the Initial Purchasers not more than
$100,000,000 in aggregate principal amount of its 2 1/4% Convertible
Subordinated Notes due 2006 (the "ADDITIONAL CONVERTIBLE NOTES" and, together
with the Firm Convertible Notes, the "NOTES"). As an inducement to the Initial
Purchasers to enter into the purchase agreement, dated as of December 5, 2001
(the "PURCHASE AGREEMENT"), and in satisfaction of a condition to the Initial
Purchasers' obligations thereunder, the Company agrees with the Initial
Purchasers, (i) for the benefit of the Initial Purchasers and (ii) for the
benefit of the holders from time to time of the Notes whose names appear in the
register maintained by the Registrar in accordance with the provisions of the
Indenture (as defined in Section 1 hereof) (including the Initial Purchasers),
as follows:

SECTION 1. DEFINITIONS

     Capitalized terms used herein without definition shall have their
respective meanings set forth in the Purchase Agreement. As used in this
Agreement, the following capitalized defined terms shall have the following
meanings:

     "ACT" means the Securities Act of 1933, as amended, and the rules and
regulations of the Commission promulgated thereunder.

     "AFFILIATE" of any specified person means any other person which, directly
or indirectly, is in control of, is controlled by, or is under common control
with, such specified person. For purposes of this definition, control of a
person means the power, direct or indirect, to direct or cause the direction of
the management and policies of such person whether by contract or otherwise; and
the terms "controlling" and "controlled" have meanings correlative to the
foregoing.

     "AGREEMENT" means this Registration Rights Agreement.

     "CLOSING DATE" has the meaning set forth in the Purchase Agreement.

     "COMMISSION" means the Securities and Exchange Commission.

     "COMMON STOCK" means the common stock of the Company, par value $0.01 per
share, issuable upon the conversion of the Notes.

     "EXCHANGE ACT" means the Securities Exchange Act of 1934, as amended, and
the rules and regulations of the Commission promulgated thereunder.

     "HOLDER" has the meaning set forth in Section 2 hereof.

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     "INDENTURE" means the Indenture, dated as of December 11, 2001, between the
Company and the Trustee, relating to the Notes, as the same may be amended from
time to time in accordance with the terms thereof.

     "INITIAL PLACEMENT" has the meaning set forth in the preamble hereto.

     "MAJORITY HOLDERS" means the Holders of a majority of the aggregate
principal amount of securities registered under a Shelf Registration Statement.

     "PROSPECTUS" means the prospectus included in any Shelf Registration
Statement (including, without limitation, a prospectus that discloses
information previously omitted from a prospectus filed as part of an effective
registration statement in reliance upon Rule 430A under the Act), as amended or
supplemented by any prospectus supplement, with respect to the terms of the
offering of any portion of Transfer Restricted Securities covered by such Shelf
Registration Statement, and all amendments and supplements to the Prospectus,
including post-effective amendments.

     "SHELF REGISTRATION" means a registration effected pursuant to Section 3
hereof.

     "SHELF REGISTRATION PERIOD" has the meaning set forth in Section 3 hereof.

     "SHELF REGISTRATION STATEMENT" means a "shelf" registration statement of
the Company pursuant to the provisions of Section 3 hereof that covers some or
all of the Transfer Restricted Securities as applicable, on an appropriate form
under Rule 415 under the Act, or any similar rule that may be adopted by the
Commission, amendments and supplements to such registration statement, including
post-effective amendments, and in each case, including the Prospectus contained
therein, all exhibits thereto and all material incorporated therein by
reference.

     "SUPPLEMENTAL DELAY PERIOD" means any period commencing on the date of
receipt by a Holder of Transfer Restricted Securities of any notice from the
Company of the existence of any fact or event of the kind described in Section
4(b)(2) hereof and ending on the date of receipt by such Holder of an amended or
supplemented Shelf Registration Statement or Prospectus, as contemplated by
Section 4(h) hereof, or the receipt by such Holder of written notice from the
Company (the "ADVICE") that the use of the Prospectus may be resumed, and the
receipt of copies of any additional or supplemental filings that are
incorporated by reference in the Prospectus.

     "TRANSFER RESTRICTED SECURITIES" means each Note and the Common Stock
issuable upon conversion thereof until (i) the date on which such Note or the
Common Stock issuable upon conversion thereof has been effectively registered
under the Act and disposed of in accordance with the Shelf Registration
Statement, (ii) the date on which such Note or Common Stock issuable upon
conversion thereof is distributed to the public pursuant to Rule 144 under the
Act (or any similar provision then in effect) or is salable pursuant to Rule
144(k) under the Act or (iii) the date on which such Note or the Common Stock
issuable upon conversion thereof ceases to be outstanding.

     "TRUSTEE" means the trustee with respect to the Notes under the Indenture.

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     "UNDERWRITER" means any underwriter of Notes in connection with an offering
thereof under a Shelf Registration Statement.

SECTION 2. HOLDERS

     A person is deemed to be a holder of Transfer Restricted Securities (each,
a "HOLDER") whenever such person becomes the registered holder of such Transfer
Restricted Securities under the Indenture and includes broker-dealers that hold
Transfer Restricted Securities (i) as a result of market making activities and
other trading activities and (ii) which were acquired directly from the Company
or an Affiliate of the Company.

SECTION 3. SHELF REGISTRATION

     The Company shall within 90 days of the date of original issuance of the
Notes, file with the Commission and thereafter shall use its reasonable best
efforts to cause to be declared effective under the Act on or prior to 180 days
(plus any additional days allowed as a result of a Supplemental Delay Period)
after the date of original issuance of the Notes, a Shelf Registration Statement
relating to the offer and sale of the Transfer Restricted Securities by the
Holders from time to time in accordance with the methods of distribution elected
by such Holders and set forth in such Shelf Registration Statement.

     The Company shall use its best efforts to keep the Shelf Registration
Statement continuously effective in order to permit the Prospectus forming part
thereof to be usable by Holders for a period of two years from the date of
original issuance of the Notes or such shorter period that will terminate when
(i) all the Transfer Restricted Securities covered by the Shelf Registration
Statement have been sold pursuant to the Shelf Registration Statement, (ii) the
date on which, in the opinion of counsel to the Company, all of the Transfer
Restricted Securities then held by the Holders may be sold by such Holders in
the public United States securities markets in the absence of a registration
statement covering such sales or (iii) the date on which there ceases to be
outstanding any Transfer Restricted Securities (in any such case, such period
being called the "SHELF REGISTRATION PERIOD"). The Company shall be deemed not
to have used its reasonable best efforts to keep the Shelf Registration
Statement effective during the requisite period if it voluntarily takes any
action that would result in Holders of Transfer Restricted Securities covered
thereby not being able to offer and sell such securities during that period,
unless (i) such action is required by applicable law, (ii) such action is taken
by the Company in good faith and for valid business reasons (not including
avoidance of the Company's obligations hereunder), including the acquisition or
divestiture of assets, so long as the Company promptly thereafter complies with
the requirements of Section 4(h) hereof, if applicable or (iii) such action is
taken because of any fact or circumstance giving rise to a Supplemental Delay
Period.

SECTION 4. REGISTRATION PROCEDURES

     In connection with any Shelf Registration Statement, the following
provisions shall apply:

     (a)  The Company shall ensure that (i) any Shelf Registration Statement and
any amendment thereto and any Prospectus forming part thereof and any amendment
or supplement thereto complies in all material respects with the Act and the
rules and regulations thereunder,

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(ii) any Shelf Registration Statement and any amendment thereto does not, when
it becomes effective, contain an untrue statement of a material fact or omit to
state a material fact required to be stated therein or necessary to make the
statements therein not misleading and (iii) any Prospectus forming part of any
Shelf Registration Statement, and any amendment or supplement to such
Prospectus, does not include an untrue statement of a material fact or omit to
state a material fact necessary in order to make the statements, in the light of
the circumstances under which they were made, not misleading.

     (b)  (1) The Company shall advise the Initial Purchasers and the Holders
of Transfer Restricted Securities named in any Shelf Registration Statement that
have provided in writing to the Company a telephone or facsimile number and
address for notices, and, if requested by the Initial Purchasers or any such
Holder, confirm such advice in writing when a Shelf Registration Statement and
any amendment thereto has been filed with the Commission and when the Shelf
Registration Statement or any post-effective amendment thereto has become
effective.

          (2) The Company shall advise the Initial Purchasers and the Holders of
Transfer Restricted Securities named in any Shelf Registration Statement, which
have provided in writing to the Company a telephone or facsimile number and
address for notices, and, if requested by the Initial Purchasers or any such
Holder, confirm such advice in writing:

          (i)   of any request by the  Commission  for amendments or supplements
to the Shelf  Registration  Statement or the Prospectus  included therein or for
additional information;

          (ii)  of the initiation by the Commission of proceedings relating to a
stop order suspending the effectiveness of the Shelf Registration Statement;

          (iii) of the issuance by the Commission of any stop order suspending
     the effectiveness of the Shelf Registration Statement;

          (iv)  of the receipt by the Company of any  notification  with respect
to the suspension of the  qualification  of the securities  included therein for
sale in any  jurisdiction or the initiation or threatening of any proceeding for
such purpose; and

          (v)   of the  existence  of any fact and the  happening  of any  event
that,  in the opinion of the Company,  makes untrue any  statement of a material
fact made in its Shelf Registration  Statement,  the Prospectus or any amendment
or  supplement  thereto or any document  incorporated  by  reference  therein or
requires  the making of any changes in the Shelf  Registration  Statement or the
Prospectus so that, as of such date, the  statements  therein are not misleading
and do not omit to state a  material  fact  required  to be  stated  therein  or
necessary  to make the  statements  therein (in the case of the  Prospectus,  in
light of the circumstances under which they were made) not misleading.

     Such advice may be accompanied by an instruction to suspend the use of the
Prospectus until the requisite changes have been made.

     (c)  The Company shall use its best efforts to obtain the withdrawal of any
order suspending the effectiveness of any Shelf Registration Statement at the
earliest possible time.

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     (d)  The Company shall use its best efforts to furnish to each selling
Holder named in any Shelf Registration Statement who so requests in writing and
who has provided to the Company an address for notices, without charge, at least
one conformed copy of such Shelf Registration Statement and any post-effective
amendment thereto, including financial statements and, if the Holder so requests
in writing, all exhibits and schedules (including those incorporated by
reference).

     (e)  The Company shall, during the Shelf Registration Period, deliver to
each Holder of Transfer Restricted Securities named in any Shelf Registration
Statement and who has provided to the Company an address for notices, without
charge, as many copies of the Prospectus (including each preliminary Prospectus)
contained in such Shelf Registration Statement and any amendment or supplement
thereto as such Holder may reasonably request; subject to any notice by the
Company in accordance with Section 5(b) hereof, the Company consents to the use
of the Prospectus or any amendment or supplement thereto by each of the selling
Holders for the purposes of offering and resale of the Transfer Restricted
Securities covered by the Prospectus in accordance with the applicable
regulations promulgated under the Act.

     (f)  Prior to any offering of Transfer Restricted Securities pursuant to
any Shelf Registration Statement, the Company shall register or qualify or
cooperate with the Holders of Transfer Restricted Securities named therein and
their respective counsel in connection with the registration or qualification of
such Transfer Restricted Securities for offer and sale under the securities or
blue sky laws of such jurisdictions of the United States as any such Holders
reasonably request in writing not later than the date that is five business days
prior to the date upon which this Agreement specifies that the Shelf
Registration Statement shall become effective; PROVIDED, HOWEVER, that the
Company will not be required to qualify generally to do business in any
jurisdiction where it is not then so qualified or to take any action which would
subject it to general or unlimited service of process or to taxation in any such
jurisdiction where it is not then so subject.

     (g)  The Company shall endeavor to cooperate with the Holders of Transfer
Restricted Securities to facilitate the timely preparation and delivery of
certificates representing Transfer Restricted Securities to be sold pursuant to
any Shelf Registration Statement free of any restrictive legends and in such
denominations and registered in such names as Holders may request in writing at
least two business days prior to sales of securities pursuant to such Shelf
Registration Statement.

     (h)  Upon the occurrence of any event contemplated by paragraph 4(b)(2)(v)
hereof, the Company shall promptly prepare a post-effective amendment to any
Shelf Registration Statement or an amendment or supplement to the related
Prospectus or file any other required document so that as thereafter delivered
to purchasers of the Transfer Restricted Securities covered thereby, the
Prospectus will not include an untrue statement of a material fact or omit to
state any material fact necessary to make the statements therein, in the light
of the circumstances under which they were made, not misleading; PROVIDED that
in the event of a material business transaction (including, without limitation,
pending negotiations relating to such a transaction) which would, in the opinion
of counsel to the Company, require disclosure by the Company in the Shelf
Registration Statement of material non-public information for which the Company
has

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a bona fide business purpose for not disclosing, then for so long as such
circumstances exist, the Company shall not be required to prepare and file a
supplement or post-effective amendment hereunder.

     (i)  Not later than the effective date of any such Shelf Registration
Statement hereunder, the Company shall cause to be provided a CUSIP number for
the Notes registered under such Shelf Registration Statement, and provide the
applicable trustee with certificates for such Notes in a form eligible for
deposit with The Depository Trust Company.

     (j)  During the twelve-month period commencing after effectiveness of the
Shelf Registration Statement, the Company shall make generally available to its
security holders in a regular filing on Form 10-Q or 10-K an earnings statement
satisfying the provisions of Rule 158 (which need not be audited).

     (k)  The Company shall cause the Indenture to be qualified under the Trust
Indenture Act in a timely manner.

     (l)  The Company may require each Holder of Transfer Restricted Securities,
which are to be sold pursuant to any Shelf Registration Statement, to furnish to
the Company within 20 business days after written request for such information
has been made by the Company, such information regarding the Holder and the
distribution of such securities as the Company may from time to time reasonably
require for inclusion in such Shelf Registration Statement and such other
information as may be necessary or advisable in the reasonable opinion of the
Company and its counsel, in connection with such Shelf Registration Statement.
No Holder of Transfer Restricted Securities shall be entitled to the benefit of
any Special Interest (as set forth in the Notes) under the Indenture and the
Notes or be entitled to use the Prospectus unless and until such Holder shall
have furnished the information required by this Section 4(l) and all such
information required to be disclosed in order to make the information previously
furnished to the Company by such Holder not materially misleading.

     (m)  The Company shall, if requested, promptly incorporate in a Prospectus
supplement or post-effective amendment to a Shelf Registration Statement, such
information as the Majority Holders reasonably agree should be included therein
in order to effect their distribution of the Notes and shall make all required
filings of such Prospectus supplement or post-effective amendment as soon as
notified of the matters to be incorporated in such Prospectus supplement or
post-effective amendment; PROVIDED, HOWEVER, that the Company shall not be
required to take any action pursuant to this Section 4(m) that would, in the
opinion of counsel for the Company, violate applicable law or to include
information the disclosure of which at the time would have a material adverse
effect on the business or operations of the Company and/or its subsidiaries, as
determined in good faith by the Company.

     (n)  The Company shall enter into such agreements and take all other
reasonably appropriate actions in order to expedite or facilitate the
registration or the disposition of the Transfer Restricted Securities, and in
connection therewith, if an underwriting agreement is entered into, cause the
same to contain indemnification and contribution provisions and procedures no
less favorable than those set forth in Section 7 (or such other provisions and

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procedures acceptable to the Majority Holders), with respect to all parties to
be indemnified pursuant to Section 7.

     (o)  The Company shall upon receipt of a reasonable request in writing
therefor:

          (i)   make reasonably available at reasonable times prior to the
     effectiveness of the related Shelf Registration Statement for inspection by
     representatives of the Holders of Transfer Restricted Securities to be
     registered thereunder and any attorney, accountant or other agent retained
     by such Holders, at the office where normally kept during normal business
     hours, all financial and other records, pertinent corporate documents and
     properties of the Company and its subsidiaries, and cause the Company's
     officers, directors and employees to supply all relevant information
     reasonably requested by the Holders' attorneys, accountants or other agents
     in connection with any such Shelf Registration Statement as is customary
     for similar due diligence examinations; PROVIDED, HOWEVER, that the
     foregoing inspection and information gathering shall be coordinated by one
     counsel designated by the Holders and that such persons shall first agree
     in writing with the Company that any information that is designated in
     writing by the Company, in good faith, as confidential at the time of
     delivery of such information shall be kept confidential by such person,
     unless such disclosure is made in connection with a court proceeding or
     required by law, or such information becomes available to the public
     generally or through a third party without an accompanying obligation of
     confidentiality;

          (ii)  obtain opinions of counsel to the Company and updates thereof
     (which counsel and opinions (in form, scope and substance) shall be
     reasonably satisfactory to the Majority Holders), addressed to each selling
     Holder named in the Shelf Registration Statement covering such matters (in
     form, scope and substance) as those matters set forth in Section 9(e) of
     the Purchase Agreement;

          (iii) obtain "cold comfort" letters (or, in the case of any person
     that does not satisfy the conditions for receipt of a "cold comfort" letter
     specified in Statement on Auditing Standards No. 72, an "agreed-upon
     procedures letter") and updates thereof from the independent certified
     public accountants of the Company (and, if necessary, any other independent
     certified public accountants of any subsidiary of the Company or of any
     business acquired by the Company for which financial statements and
     financial data are, or are required to be, included in the Shelf
     Registration Statement), addressed to each selling Holder of Transfer
     Restricted Securities registered thereunder and the underwriters, if any,
     in customary form and covering matters of the type customarily covered in
     "cold comfort" letters in connection with primary underwritten offerings;
     and

          (iv)  deliver such documents and certificates as may be reasonably
     requested by the Majority Holders, including those to evidence compliance
     with Section 4(h).

          The foregoing actions set forth in clauses (ii), (iii) and (iv) of
this Section 4(o) shall be performed upon the effectiveness of such Shelf
Registration Statement and the effectiveness of each post-effective amendment
thereto.

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     (p)  The Company may offer securities of the Company other than the Notes
under the Shelf Registration Statement, except where such offer would
conflict with the terms of the Purchase Agreement.

SECTION 5. HOLDERS' AGREEMENTS

     Each Holder of Transfer Restricted Securities severally but not jointly, by
the acquisition of such Transfer Restricted Securities, agrees:

     (a)  To furnish the information required to be furnished pursuant to
Section 4(l) hereof within the time period set forth therein.

     (b)  That upon receipt of a notice of the commencement of a Supplemental
Delay Period, it will keep the fact of such notice confidential, forthwith
discontinue disposition of its Transfer Restricted Securities pursuant to the
Shelf Registration Statement, and will not deliver any Prospectus forming a part
thereof until receipt of the amended or supplemented Shelf Registration
Statement or Prospectus, as applicable, as contemplated by Section 4(h) hereof,
or until receipt of the Advice. If a Supplemental Delay Period should occur, the
Shelf Registration Period shall be extended by the number of days of which the
Supplemental Delay Period is comprised; PROVIDED that the Shelf Registration
Period shall not be extended if the Company has received an opinion of counsel
(which counsel, if different from counsel to the Company referred to in Section
9(e) of the Purchase Agreement, shall be reasonably satisfactory to the Majority
Holders of the Transfer Restricted Securities named in the Shelf Registration
Period and which opinion shall be in writing) to the effect that the Transfer
Restricted Securities can be freely tradable without the continued effectiveness
of the Shelf Registration Statement.

     (c)  If so directed by the Company in a notice of the commencement of a
Supplemental Delay Period, each Holder of Transfer Restricted Securities will
deliver to the Company (at the Company's expense) all copies, other than
permanent file copies then in such Holder's possession, of the Prospectus
covering the Transfer Restricted Securities.

     (d)  Sales of such Transfer Restricted Securities pursuant to a Shelf
Registration Statement shall only be made in the manner set forth in such
currently effective Shelf Registration Statement.

SECTION 6. REGISTRATION EXPENSES

     The Company shall bear all expenses incurred in connection with the
performance of its obligations under Sections 3 and 4 hereof and will reimburse
the Holders for the reasonable fees and disbursements of one firm or counsel
designated by the Majority Holders to act as counsel for the Holders in
connection with any Shelf Registration Statement. Notwithstanding the foregoing
or anything in this Agreement to the contrary, each Holder shall pay all
underwriting discounts and commission of any underwriters with respect to any
Transfer Restricted Securities sold by it.

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SECTION 7. INDEMNIFICATION AND CONTRIBUTION

     (a)  The Company agrees to indemnify and hold harmless each Holder and each
person, if any, who controls such Holder within the meaning of the Act or the
Exchange Act (each Holder, and such controlling persons are referred to
collectively as the "Indemnified Parties") from and against any losses, claims,
damages or liabilities, joint or several, or any actions in respect thereof
(including, but not limited to, any losses, claims, damages, liabilities or
actions relating to purchases and sales of the Securities) to which each
Indemnified Party may become subject under the Act, the Exchange Act or
otherwise, insofar as such losses, claims, damages, liabilities or actions arise
out of or are based upon any untrue statement or alleged untrue statement of a
material fact contained in the Shelf Registration Statement or Prospectus
including any document incorporated by reference therein, or in any amendment or
supplement thereto or in any preliminary prospectus relating to the Shelf
Registration, or arise out of, or are based upon, the omission or alleged
omission to state therein a material fact required to be stated therein or
necessary to make the statements therein not misleading, and shall reimburse, as
incurred, the Indemnified Parties for any legal or other expenses reasonably
incurred by them in connection with investigating or defending any such loss,
claim, damage, liability or action in respect thereof; PROVIDED, HOWEVER, that
(i) the Company shall not be liable in any such case to the extent that such
loss, claim, damage or liability arises out of or is based upon any untrue
statement or alleged untrue statement or omission or alleged omission made in
the Shelf Registration Statement or Prospectus or in any amendment or supplement
thereto or in any preliminary prospectus relating to the Shelf Registration in
reliance upon and in conformity with written information pertaining to such
Holder and furnished to the Company by or on behalf of such Holder specifically
for inclusion therein and (ii) with respect to any untrue statement or omission
or alleged untrue statement or omission made in any preliminary prospectus
relating to the Shelf Registration Statement, the indemnity agreement contained
in this subsection (a) shall not inure to the benefit of any Holder from whom
the person asserting any such losses, claims, damages or liabilities purchased
the securities concerned, to the extent that a prospectus relating to such
securities was required to be delivered by such Holder under the Act in
connection with such purchase and any such loss, claim, damage or liability of
such Holder results from the fact that there was not sent or given to such
person, at or prior to the written confirmation of the sale of such securities
to such person, a copy of the final Prospectus if the Company had previously
furnished copies thereof to such Holder; PROVIDED FURTHER, HOWEVER, that this
indemnity agreement will be in addition to any liability which the Company may
otherwise have to such Indemnified Party. The Company shall also indemnify
underwriters, their officers and directors and each person who controls such
underwriters within the meaning of the Act or the Exchange Act to the same
extent as provided above with respect to the indemnification of the Holders if
requested by such Holders.

     (b) Each Holder, severally and not jointly, will indemnify and hold
harmless the Company, its officers and directors and each person, if any, who
controls the Company within the meaning of the Act or the Exchange Act from and
against any losses, claims, damages or liabilities or any actions in respect
thereof, to which the Company or any such controlling person may become subject
under the Act, the Exchange Act or otherwise, insofar as such losses, claims,
damages, liabilities or actions arise out of or are based upon any untrue
statement or alleged untrue statement of a material fact contained in the Shelf
Registration Statement or Prospectus or in any amendment or supplement thereto
or in any preliminary prospectus relating

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to the Shelf Registration, or arise out of or are based upon the omission or
alleged omission to state therein a material fact necessary to make the
statements therein not misleading, but in each case only to the extent that the
untrue statement or omission or alleged untrue statement or omission was made in
reliance upon and in conformity with written information pertaining to such
Holder and furnished to the Company by or on behalf of such Holder specifically
for inclusion therein; and, subject to the limitation set forth immediately
preceding this clause, shall reimburse, as incurred, the Company for any legal
or other expenses reasonably incurred by the Company or any such controlling
person in connection with investigating or defending any loss, claim, damage,
liability or action in respect thereof. This indemnity agreement will be in
addition to any liability which such Holder may otherwise have to the Company or
any of its controlling persons.

     (c)  Promptly after receipt by an indemnified party under this Section 7 of
notice of the commencement of any action or proceeding (including a governmental
investigation), such indemnified party will, if a claim in respect thereof is to
be made against the indemnifying party under this Section 7, notify the
indemnifying party of the commencement thereof; but the omission so to notify
the indemnifying party will not, in any event, relieve the indemnifying party
from any obligations to any indemnified party other than the indemnification
obligation provided in paragraph (a) or (b) above. In case any such action is
brought against any indemnified party, and it notifies the indemnifying party of
the commencement thereof, the indemnifying party will be entitled to participate
therein and, to the extent that it may wish, jointly with any other indemnifying
party similarly notified, to assume the defense thereof, with counsel reasonably
satisfactory to such indemnified party (who shall not, except with the consent
of the indemnified party, be counsel to the indemnifying party), and after
notice from the indemnifying party to such indemnified party of its election so
to assume the defense thereof the indemnifying party will not be liable to such
indemnified party under this Section 7 for any legal or other expenses, other
than reasonable costs of investigation, subsequently incurred by such
indemnified party in connection with the defense thereof. No indemnifying party
shall, without the prior written consent of the indemnified party, effect any
settlement of any pending or threatened action in respect of which any
indemnified party is or could have been a party and indemnity could have been
sought hereunder by such indemnified party unless such settlement (i) includes
an unconditional release of such indemnified party from all liability on any
claims that are the subject matter of such action, and (ii) does not include a
statement as to or an admission of fault, culpability or a failure to act by or
on behalf of any indemnified party.

     (d)  If the indemnification provided for in this Section 7 is unavailable
or insufficient to hold harmless an indemnified party under subsections (a) or
(b) above, then each indemnifying party shall contribute to the amount paid or
payable by such indemnified party as a result of the losses, claims, damages or
liabilities (or actions in respect thereof) referred to in subsection (a) or (b)
above in such proportion as is appropriate to reflect the relative fault of the
indemnifying party or parties on the one hand and the indemnified party on the
other in connection with the statements or omissions that resulted in such
losses, claims, damages or liabilities (or actions in respect thereof) as well
as any other relevant equitable considerations. The relative fault of the
parties shall be determined by reference to, among other things, whether the
untrue or alleged untrue statement of a material fact or the omission or alleged
omission to state a material fact relates to information supplied by the Company
on the one hand or such

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Holder or such other indemnified party, as the case may be, on the other, and
the parties' relative intent, knowledge, access to information and opportunity
to correct or prevent such statement or omission. The amount paid by an
indemnified party as a result of the losses, claims, damages or liabilities
referred to in the first sentence of this subsection (d) shall be deemed to
include any legal or other expenses reasonably incurred by such indemnified
party in connection with investigating or defending any action or claim which is
the subject of this subsection (d). Notwithstanding any other provision of this
Section 7(d), the Holders shall not be required to contribute any amount in
excess of the amount by which the net proceeds received by such Holders from the
sale of the securities pursuant to the Shelf Registration Statement exceeds the
amount of damages which such Holders have otherwise been required to pay by
reason of such untrue or alleged untrue statement or omission or alleged
omission. No person guilty of fraudulent misrepresentation (within the meaning
of Section 11(f) of the Act) shall be entitled to contribution from any person
who was not guilty of such fraudulent misrepresentation. For purposes of this
paragraph (d), each person, if any, who controls such indemnified party within
the meaning of the Act or the Exchange Act shall have the same rights to
contribution as such indemnified party and each person, if any, who controls the
Company within the meaning of the Act or the Exchange Act shall have the same
rights to contribution as the Company.

     (e)  The agreements contained in this Section 7 shall survive the sale of
the securities pursuant to the Shelf Registration Statement and shall remain in
full force and effect, regardless of any termination or cancellation of this
Agreement or any investigation made by or on behalf of any indemnified party.

SECTION 8. RULE 144A AND RULE 144

     The Company agrees with each Holder, for so long as any Transfer Restricted
Securities remain outstanding and during any period in which the Company (i) is
not subject to Section 13 or 15(d) of the Exchange Act, to make available, upon
request of any Holder, to such Holder or beneficial owner of Transfer Restricted
Securities in connection with any sale thereof and any prospective purchaser of
such Transfer Restricted Securities designated by such Holder or beneficial
owner, the information required by Rule 144A(d)(4) under the Act in order to
permit resales of such Transfer Restricted Securities pursuant to Rule 144A, and
(ii) is subject to Section 13 or 15 (d) of the Exchange Act, to make all filings
required thereby in a timely manner in order to permit resales of such Transfer
Restricted Securities pursuant to Rule 144.

SECTION 9. MISCELLANEOUS

     (a)  NO INCONSISTENT AGREEMENTS. The Company has not, as of the date
hereof, entered into, nor shall it, on or after the date hereof, enter into, any
agreement with respect to its securities that is inconsistent with the rights
granted to the Holders herein or otherwise conflicts with the provisions hereof.

     (b)  AMENDMENTS AND WAIVERS. The provisions of this Agreement, including
the provisions of this sentence, may not be amended, qualified, modified or
supplemented, and waivers or consents to departures from the provisions hereof
may not be given, unless the Company has obtained the written consent of the
Holders of at least a majority of the then outstanding aggregate principal
amount of Notes; PROVIDED, HOWEVER, that with respect to any

                                       11
<Page>

matter that directly or indirectly affects the rights of any Initial Purchaser
hereunder, the Company shall obtain the written consent of each such Initial
Purchaser against which such amendment, qualification, supplement, waiver or
consent is to be effective. Notwithstanding the foregoing (except the foregoing
proviso), a waiver or consent to depart from the provisions hereof, with respect
to a matter, which relates exclusively to the rights of Holders whose securities
are being sold pursuant to a Shelf Registration Statement and does not directly
or indirectly affect the rights of other Holders, may be given by the Majority
Holders, determined on the basis of Notes being sold rather than registered
under such Shelf Registration Statement.

     (c)  NOTICES. All notices and other communications provided for or
permitted hereunder shall be made in writing by hand-delivery, first-class mail,
telex, telecopier, or air courier guaranteeing overnight delivery:

          (i)   if to a Holder, at the most current address given by such holder
to the Company in accordance  with the  provisions  of this Section 9(c),  which
address  initially  is, with respect to each Holder,  the address of such Holder
maintained by the registrar under the Indenture;

          (ii)  with a copy  in  like  manner  to  Credit  Suisse  First  Boston
Corporation;

          (iii) if to the Initial Purchasers, initially at the respective
     addresses set forth in the Purchase Agreement; and

          (iv)  if to the  Company,  initially  at its  address set forth in the
Purchase Agreement.

     All such notices and communications shall be deemed to have been duly given
when received.

     Upon the date of filing of a Shelf Registration Statement notice shall be
delivered to Credit Suisse First Boston Corporation, on behalf of the Initial
Purchasers (in the form attached hereto as Exhibit A) and shall be addressed to:
Attention: Transactions Advisory Group, Eleven Madison Avenue, New York, New
York 10010-3629.

     The Initial Purchasers or the Company by notice to the other may designate
additional or different addresses for subsequent notices or communications.

     (d)  SUCCESSORS AND ASSIGNS. This Agreement shall inure to the benefit of,
and be binding upon, the successors and assigns of each of the parties hereto,
including, without the need for an express assignment or any consent by the
Company thereto, subsequent Holders of Notes. The Company hereby agrees to
extend the benefits of this Agreement to any Holder of Notes and any such Holder
may specifically enforce the provisions of this Agreement as if an original
party hereto.

     (e)  COUNTERPARTS. This agreement may be executed in any number of
counterparts and by the parties hereto in separate counterparts, each of which
when so executed shall be deemed to be an original, and all of which taken
together shall constitute one and the same agreement.

                                       12
<Page>

     (f)  HEADINGS. The headings in this agreement are for convenience of
reference only and shall not limit or otherwise affect the meaning hereof.

     (g)  GOVERNING LAW. This agreement shall be governed by and construed in
accordance with the internal laws of the State of New York applicable to
agreements made and to be performed in said State (without reference to the
conflict of law rules thereof).

     (h)  SEVERABILITY. In the event that any one or more of the provisions
contained herein, or the application thereof in any circumstances, is held
invalid, illegal or unenforceable in any respect for any reason, the validity,
legality and enforceability of any such provision in every other respect and the
remaining provisions hereof shall not be in any way impaired or affected
thereby, it being intended that all of the rights and privileges of the parties
shall be enforceable to the fullest extent permitted by law.

     (i)  NOTES HELD BY THE COMPANY, ETC. Whenever the consent or approval of
Holders of a specified percentage of principal amount of Notes is required
hereunder, Notes held by the Company or its Affiliates (other than subsequent
Holders of Notes if such subsequent Holders are deemed to be Affiliates solely
by reason of their holdings of such Notes) shall not be counted in determining
whether such consent or approval was given by the Holders of such required
percentage.

     (j)  ENTIRE AGREEMENT. This Agreement is intended by the parties as a final
expression of their agreement and intended to be a complete and exclusive
statement of the agreement and understanding of the parties hereto with respect
to the subject matter contained herein. There are no restrictions, promises,
warranties or undertakings, other than those set forth or referred to herein
with respect to the registration rights granted with respect to the Transfer
Restricted Securities. This Agreement supersedes all prior agreements and
understandings between the parties with respect to such subject matter.

                                       13
<Page>

     IN WITNESS WHEREOF, the parties have executed this Agreement as of the date
first written above.

                                             INVITROGEN CORPORATION

                                             By:
                                                 -------------------------------
                                             Name:
                                             Title:

                                       14
<Page>

CREDIT SUISSE FIRST BOSTON CORPORATION
UBS WARBURG LLC

BY:    CREDIT SUISSE FIRST BOSTON CORPORATION

By:
    -------------------------------------------------
    Name:
    Title:

                                       15
<Page>

                                    EXHIBIT A

                               NOTICE OF FILING OF
                          SHELF REGISTRATION STATEMENT

To:    Credit Suisse First Boston Corporation
       Eleven Madison Avenue
       New York, New York  10010-3629
       Attention:  Transactions Advisory Group
       Fax:  (212) 325-8278

From:  Invitrogen Corporation
       2 1/4% Convertible Subordinated Notes due 2006

Date:  _________________, 200_

       For your information only (NO ACTION REQUIRED):

Today, _______________, 200_, we filed a Shelf Registration Statement with the
Securities and Exchange Commission.

                                       16<Page>
                                                                     Exhibit 4.5

================================================================================

                             INVITROGEN CORPORATION

                 2 1/4% CONVERTIBLE SUBORDINATED NOTES DUE 2006

                                 --------------

                                   INDENTURE
                         DATED AS OF DECEMBER 11, 2001

                                 --------------

             STATE STREET BANK AND TRUST COMPANY CALIFORNIA, N.A.,
                                   AS TRUSTEE

================================================================================

<Page>

                                TABLE OF CONTENTS

<Table>
<Caption>
                                                                                                                   PAGE
<S>                            <C>                                                                                   <C>
ARTICLE 1 DEFINITIONS AND INCORPORATION BY REFERENCE..................................................................1

         SECTION 1.1.          DEFINITIONS............................................................................1
         SECTION 1.2.          OTHER DEFINITIONS......................................................................6
         SECTION 1.3.          TRUST INDENTURE ACT PROVISIONS.........................................................7
         SECTION 1.4.          RULES OF CONSTRUCTION..................................................................7

ARTICLE 2 THE SECURITIES..............................................................................................8

         SECTION 2.1.          FORM AND DATING........................................................................8
         SECTION 2.2.          EXECUTION AND AUTHENTICATION...........................................................9
         SECTION 2.3.          REGISTRAR, PAYING AGENT AND CONVERSION AGENT..........................................10
         SECTION 2.4.          PAYING AGENT TO HOLD MONEY IN TRUST...................................................10
         SECTION 2.5.          SECURITYHOLDER LISTS..................................................................11
         SECTION 2.6.          TRANSFER AND EXCHANGE.................................................................11
         SECTION 2.7.          REPLACEMENT SECURITIES................................................................12
         SECTION 2.8.          OUTSTANDING SECURITIES................................................................13
         SECTION 2.9.          TREASURY SECURITIES...................................................................13
         SECTION 2.10.         TEMPORARY SECURITIES..................................................................13
         SECTION 2.11.         CANCELLATION..........................................................................13
         SECTION 2.12.         LEGEND; ADDITIONAL TRANSFER AND EXCHANGE REQUIREMENTS.................................14
         SECTION 2.13.         CUSIP NUMBERS.........................................................................16

ARTICLE 3 REDEMPTION AND PURCHASES...................................................................................16

         SECTION 3.1.          RIGHT TO REDEEM; NOTICE TO TRUSTEE....................................................16
         SECTION 3.2.          SELECTION OF SECURITIES TO BE REDEEMED................................................17
         SECTION 3.3.          NOTICE OF REDEMPTION..................................................................17
         SECTION 3.4.          EFFECT OF NOTICE OF REDEMPTION........................................................18
         SECTION 3.5.          DEPOSIT OF REDEMPTION PRICE...........................................................18
         SECTION 3.6.          SECURITIES REDEEMED IN PART...........................................................18
         SECTION 3.7.          CONVERSION ARRANGEMENT ON CALL FOR REDEMPTION.........................................18
         SECTION 3.8.          PURCHASE OF SECURITIES AT OPTION OF THE HOLDER UPON CHANGE IN CONTROL.................19
         SECTION 3.9.          COMPLIANCE WITH SECURITIES LAWS UPON PURCHASE OF SECURITIES...........................21
         SECTION 3.10.         REPAYMENT TO THE COMPANY..............................................................22

ARTICLE 4 CONVERSION.................................................................................................22

         SECTION 4.1.          CONVERSION PRIVILEGE..................................................................22
         SECTION 4.2.          CONVERSION PROCEDURE..................................................................22
         SECTION 4.3.          FRACTIONAL SHARES.....................................................................23
         SECTION 4.4.          TAXES ON CONVERSION...................................................................24
         SECTION 4.5.          COMPANY TO PROVIDE STOCK..............................................................24
         SECTION 4.6.          ADJUSTMENT OF CONVERSION PRICE........................................................24
         SECTION 4.7.          NO ADJUSTMENT.........................................................................29
</Table>

                                       -i-
<Page>
                                TABLE OF CONTENTS
                                  (CONTINUED)

<Table>
<Caption>
                                                                                                                   PAGE
<S>                            <C>                                                                                   <C>
         SECTION 4.8.          ADJUSTMENT FOR TAX PURPOSES...........................................................29
         SECTION 4.9.          NOTICE OF ADJUSTMENT..................................................................29
         SECTION 4.10.         NOTICE OF CERTAIN TRANSACTIONS........................................................29
         SECTION 4.11.         EFFECT OF RECLASSIFICATION, CONSOLIDATION, MERGER OR SALE ON CONVERSION
                               PRIVILEGE.............................................................................30
         SECTION 4.12.         TRUSTEE'S DISCLAIMER..................................................................31
         SECTION 4.13.         VOLUNTARY REDUCTION...................................................................31

ARTICLE 5 SUBORDINATION..............................................................................................31

         SECTION 5.1.          AGREEMENT OF SUBORDINATION............................................................31
         SECTION 5.2.          PAYMENTS TO HOLDERS...................................................................32
         SECTION 5.3.          SUBROGATION OF SECURITIES.............................................................34
         SECTION 5.4.          AUTHORIZATION TO EFFECT SUBORDINATION.................................................35
         SECTION 5.5.          NOTICE TO TRUSTEE.....................................................................35
         SECTION 5.6.          TRUSTEE'S RELATION TO SENIOR INDEBTEDNESS.............................................36
         SECTION 5.7.          NO IMPAIRMENT OF SUBORDINATION........................................................36
         SECTION 5.8.          CERTAIN CONVERSIONS DEEMED PAYMENT....................................................36
         SECTION 5.9.          ARTICLE APPLICABLE TO PAYING AGENTS...................................................36
         SECTION 5.10.         SENIOR INDEBTEDNESS ENTITLED TO RELY..................................................37

ARTICLE 6 COVENANTS..................................................................................................37

         SECTION 6.1.          PAYMENT OF SECURITIES.................................................................37
         SECTION 6.2.          SEC REPORTS...........................................................................37
         SECTION 6.3.          COMPLIANCE CERTIFICATES...............................................................38
         SECTION 6.4.          FURTHER INSTRUMENTS AND ACTS..........................................................38
         SECTION 6.5.          MAINTENANCE OF CORPORATE EXISTENCE....................................................38
         SECTION 6.6.          RULE 144A INFORMATION REQUIREMENT.....................................................38
         SECTION 6.7.          STAY, EXTENSION AND USURY LAWS........................................................38
         SECTION 6.8.          PAYMENT OF SPECIAL INTEREST...........................................................39

ARTICLE 7 CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER OR LEASE.......................................................39

         SECTION 7.1.          COMPANY MAY CONSOLIDATE, ETC, ONLY ON CERTAIN TERMS...................................39
         SECTION 7.2.          SUCCESSOR SUBSTITUTED.................................................................40

ARTICLE 8 DEFAULT AND REMEDIES.......................................................................................40

         SECTION 8.1.          EVENTS OF DEFAULT.....................................................................40
         SECTION 8.2.          ACCELERATION..........................................................................42
         SECTION 8.3.          OTHER REMEDIES........................................................................42
         SECTION 8.4.          WAIVER OF DEFAULTS AND EVENTS OF DEFAULT..............................................42
         SECTION 8.5.          CONTROL BY MAJORITY...................................................................42
         SECTION 8.6.          LIMITATIONS ON SUITS..................................................................43
         SECTION 8.7.          RIGHTS OF HOLDERS TO RECEIVE PAYMENT AND TO CONVERT...................................43
</Table>

                                      -ii-
<Page>

                                TABLE OF CONTENTS
                                  (CONTINUED)

<Table>
<Caption>
                                                                                                                   PAGE
<S>                            <C>                                                                                   <C>
         SECTION 8.8.          COLLECTION SUIT BY TRUSTEE............................................................43
         SECTION 8.9.          TRUSTEE MAY FILE PROOFS OF CLAIM......................................................44
         SECTION 8.10.         PRIORITIES............................................................................44
         SECTION 8.11.         UNDERTAKING FOR COSTS.................................................................44

ARTICLE 9 TRUSTEE....................................................................................................45

         SECTION 9.1.          DUTIES OF TRUSTEE.....................................................................45
         SECTION 9.2.          RIGHTS OF TRUSTEE.....................................................................45
         SECTION 9.3.          INDIVIDUAL RIGHTS OF TRUSTEE..........................................................46
         SECTION 9.4.          TRUSTEE'S DISCLAIMER..................................................................47
         SECTION 9.5.          NOTICE OF DEFAULT OR EVENTS OF DEFAULT................................................47
         SECTION 9.6.          REPORTS BY TRUSTEE TO HOLDERS.........................................................47
         SECTION 9.7.          COMPENSATION AND INDEMNITY............................................................47
         SECTION 9.8.          REPLACEMENT OF TRUSTEE................................................................48
         SECTION 9.9.          SUCCESSOR TRUSTEE BY MERGER, ETC......................................................49
         SECTION 9.10.         ELIGIBILITY; DISQUALIFICATION.........................................................49
         SECTION 9.11.         PREFERENTIAL COLLECTION OF CLAIMS AGAINST COMPANY.....................................49

ARTICLE 10 SATISFACTION AND DISCHARGE OF INDENTURE...................................................................49

         SECTION 10.1.         SATISFACTION AND DISCHARGE OF INDENTURE...............................................49
         SECTION 10.2.         APPLICATION OF TRUST MONEY............................................................50
         SECTION 10.3.         REPAYMENT TO COMPANY..................................................................50
         SECTION 10.4.         REINSTATEMENT.........................................................................51

ARTICLE 11 AMENDMENTS, SUPPLEMENTS AND WAIVERS.......................................................................51

         SECTION 11.1.         WITHOUT CONSENT OF HOLDERS............................................................51
         SECTION 11.2.         WITH CONSENT OF HOLDERS...............................................................51
         SECTION 11.3.         COMPLIANCE WITH TRUST INDENTURE ACT...................................................52
         SECTION 11.4.         REVOCATION AND EFFECT OF CONSENTS.....................................................53
         SECTION 11.5.         NOTATION ON OR EXCHANGE OF SECURITIES.................................................53
         SECTION 11.6.         TRUSTEE TO SIGN AMENDMENTS, ETC.......................................................53
         SECTION 11.7.         EFFECT OF SUPPLEMENTAL INDENTURES.....................................................53

ARTICLE 12 MISCELLANEOUS.............................................................................................53

         SECTION 12.1.         TRUST INDENTURE ACT CONTROLS..........................................................53
         SECTION 12.2.         NOTICES...............................................................................54
         SECTION 12.3.         COMMUNICATIONS BY HOLDERS WITH OTHER HOLDERS..........................................54
         SECTION 12.4.         CERTIFICATE AND OPINION AS TO CONDITIONS PRECEDENT....................................55
         SECTION 12.5.         RECORD DATE FOR VOTE OR CONSENT OF SECURITYHOLDERS....................................55
         SECTION 12.6.         RULES BY TRUSTEE, PAYING AGENT, REGISTRAR AND CONVERSION AGENT........................56
         SECTION 12.7.         LEGAL HOLIDAYS........................................................................56
         SECTION 12.8.         GOVERNING LAW.........................................................................56
</Table>

                                      -iii-
<Page>

                                TABLE OF CONTENTS
                                  (CONTINUED)

<Table>
<Caption>
                                                                                                                   PAGE
<S>                            <C>                                                                                   <C>
         SECTION 12.9.         NO ADVERSE INTERPRETATION OF OTHER AGREEMENTS.........................................56
         SECTION 12.10.        NO RECOURSE AGAINST OTHERS............................................................56
         SECTION 12.11.        SUCCESSORS............................................................................56
         SECTION 12.12.        MULTIPLE COUNTERPARTS.................................................................56
         SECTION 12.13.        SEPARABILITY..........................................................................56
         SECTION 12.14.        TABLE OF CONTENTS, HEADINGS, ETC......................................................57
</Table>

                                      -iv-
<Page>

                             CROSS-REFERENCE TABLE*

<Table>
<Caption>
TIA SECTION                                                                                       INDENTURE SECTION
-----------                                                                                   -----------------------
<S>               <C>                                                                         <C>
Section           310(a)(1).................................................................  9.10
                  (a)(2)....................................................................  9.10
                  (a)(3)....................................................................  N.A.**
                  (a)(4)....................................................................  N.A.
                  (a)(5)....................................................................  9.10
                  (b).......................................................................  9.8; 9.10
                  (c).......................................................................  N.A.
Section           311(a)....................................................................  9.11
                  (b).......................................................................  9.11
                  (c).......................................................................  N.A.
Section           312(a)....................................................................  2.5
                  (b).......................................................................  12.3
                  (c).......................................................................  12.3
Section           313(a)....................................................................  9.6
                  (b)(1)....................................................................  N.A.
                  (b)(2)....................................................................  9.6
                  (c).......................................................................  9.6; 12.2
                  (d).......................................................................  9.6
Section           314(a)....................................................................  6.2; 6.4; 12.2
                  (b).......................................................................  N.A.
                  (c)(1)....................................................................  12.4(a)
                  (c)(2)....................................................................  12.4(a)
                  (c)(3)....................................................................  N.A.
                  (d).......................................................................  N.A.
                  (e).......................................................................  12.4(b)
                  (f).......................................................................  N.A.
Section           315(a)....................................................................  9.1(b)
                  (b).......................................................................  9.5; 12.2
                  (c).......................................................................  9.1(a)
                  (d).......................................................................  9.1(c)
                  (e).......................................................................  8.11
Section           316(a)(last sentence).....................................................  2.9
                  (a)(1)(A).................................................................  8.5
                  (a)(1)(B).................................................................  8.4
                  (a)(2)....................................................................  N.A.
                  (b).......................................................................  8.7
                  (c).......................................................................  12.5
Section           317(a)(1).................................................................  8.8
                  (a)(2)....................................................................  8.9
                  (b).......................................................................  2.4
</Table>

----------
*    This Cross-Reference Table shall not, for any purpose, be deemed a part of
     this Indenture.
**   N.A. means Not Applicable.

<Page>

     THIS INDENTURE dated as of December 11, 2001 is between Invitrogen
Corporation, a corporation duly organized under the laws of the State of
Delaware (the "Company"), and State Street Bank and Trust Company of California,
N.A., a national banking association organized and existing under the laws of
the United States, as Trustee (the "Trustee").

     In consideration of the premises and the purchase of the Securities by the
Holders thereof, both parties agree as follows for the benefit of the other and
for the equal and ratable benefit of the registered Holders of the Company's 2
1/4% Convertible Subordinated Notes due 2006.

                                    ARTICLE 1
                   DEFINITIONS AND INCORPORATION BY REFERENCE

     SECTION 1.1. DEFINITIONS.

     "Affiliate" means, with respect to any specified person, any other person
directly or indirectly controlling or controlled by or under direct or indirect
common control with such specified person. For the purposes of this definition,
"control" when used with respect to any person means the power to direct the
management and policies of such person, directly or indirectly, whether through
the ownership of voting securities, by contract or otherwise; and the terms
"controlling" and "controlled" have meanings correlative to the foregoing.

     "Agent" means any Registrar, Paying Agent or Conversion Agent.

     "Applicable Procedures" means, with respect to any transfer or exchange of
beneficial ownership interests in a Global Security, the rules and procedures of
the Depositary, in each case to the extent applicable to such transfer or
exchange.

     "Board of Directors" means either the board of directors of the Company or
any committee of the Board of Directors authorized to act for it with respect to
this Indenture.

     "Business Day" means each day that is not a Legal Holiday.

     "Capital Stock" of any Person means any and all shares, interests, rights
to purchase, warrants, options, participations or other equivalents of or
interests in (however designated) equity of such Person, but excluding any debt
securities convertible into such equity.

     "Cash" or "cash" means such coin or currency of the United States as at any
time of payment is legal tender for the payment of public and private debts.

     "Certificated Security" means a Security that is in substantially the form
attached hereto as EXHIBIT A and that does not include the information or the
schedule called for by footnotes 1, 3 and 4 thereof.

     "Common Stock" means the common stock of the Company, $0.01 par value, as
it exists on the date of this Indenture and any shares of any class or classes
of capital stock of the Company resulting from any reclassification or
reclassifications thereof and which have no preference in respect of dividends
or of amounts payable in the event of any voluntary or involuntary liquidation,
dissolution or winding-up of the Company and which are not subject to redemption
by the Company; PROVIDED, HOWEVER, that if at any time

                                        1
<Page>

there shall be more than one such resulting class, the shares of each such class
then so issuable on conversion of Securities shall be substantially in the
proportion which the total number of shares of such class resulting from all
such reclassifications bears to the total number of shares of all such classes
resulting from all such reclassifications.

     "Company" means the party named as such in the first paragraph of this
Indenture until a successor replaces it pursuant to the applicable provisions of
this Indenture, and thereafter "Company" shall mean such successor Company.

     "Continuing Director" means, at any date of determination, any member of
the Company's Board of Directors (i) who was a member of the Company's Board of
Directors on the Issuance Date, or (ii) who was nominated for election or
elected to the Company's Board of Directors by at least a majority of the
directors who were such Continuing Directors at the time of such nomination or
election or whose election to the Company's Board of Directors was recommended
or endorsed by at least a majority of the directors who were such Continuing
Directors at the time of such nomination or election.

     "Corporate Trust Office" means the office of the Trustee at which at any
particular time the trust created by this Indenture shall be administered which
office at the date of the execution of this Indenture is located at 633 West 5th
Street, 12th Floor, Los Angeles, California 90071, Attention: Corporate Trust
Administration (Invitrogen Corporation -- 2 1/4% Convertible Subordinated Notes
Due 2006) or at any other time at such other address as the Trustee may
designate from time to time by notice to the Company.

     "Default" or "default" means, when used with respect to the Securities, any
event which is or, after notice or passage of time or both, would be an Event of
Default.

     "Designated Senior Indebtedness" means any particular Senior Indebtedness
of the Company in which the instrument creating or evidencing the same or the
assumption or guarantee thereof (or any related agreements or documents to which
the Company is a party) expressly provides that such Senior Indebtedness shall
be "Designated Senior Indebtedness" for purposes of this Indenture (PROVIDED
THAT such instrument, agreement or other document may place limitations and
conditions on the right of such Senior Indebtedness to exercise the rights of
Designated Senior Indebtedness). If any payment made to any holder of any
Designated Senior Indebtedness or its Representative with respect to such
Designated Senior Indebtedness is rescinded or must otherwise be returned by
such holder or Representative upon the insolvency, bankruptcy or reorganization
of the Company or otherwise, the reinstated Indebtedness of the Company arising
as a result of such rescission or return shall constitute Designated Senior
Indebtedness effective as of the date of such rescission or return.

     "Exchange Act" means the Securities and Exchange Act of 1934, as amended,
and the rules and regulations promulgated thereunder, as in effect from time to
time.

     "Final Maturity Date" means December 15, 2006.

     "GAAP" means generally accepted accounting principles in the United States
of America as in effect as of the date of this Indenture, including those set
forth in (1) the opinions and pronouncements of the Accounting Principles Board
of the American Institute of Certified Public Accountants, (2) the statements
and pronouncements of the Financial Accounting Standards Board, (3) such other
statements by such other entity as approved by a significant segment of the
accounting profession and (4) the rules and regulations of the SEC governing the
inclusion of financial statements (including pro forma financial statements) in
registration

                                        2
<Page>

statements filed under the Securities Act and periodic reports required to be
filed pursuant to Section 13 of the Exchange Act, including opinions and
pronouncements in staff accounting bulletins and similar written statements from
the accounting staff of the SEC.

     "Global Security" means a permanent Global Security that is in
substantially the form attached hereto as EXHIBIT A and that includes the
information and schedule called for by footnotes 1, 3 and 4 thereof and which is
deposited with the Depositary or its custodian and registered in the name of the
Depositary or its nominee.

     "Holder" or "Securityholder" means the person in whose name a Security is
registered on the Primary Registrar's books.

     "Indebtedness" means, with respect to any Person, without duplication, (a)
all indebtedness, obligations and other liabilities (contingent or otherwise) of
such Person (i) for borrowed money (including obligations of such Person in
respect of overdrafts, foreign exchange contracts, currency exchange agreements,
interest rate protection agreements, and any loans or advances from banks,
whether or not evidenced by notes or similar instruments) or (ii) evidenced by
credit or loan agreements, bonds, debentures, notes or similar instruments
(whether or not the recourse of the lender is to the whole of the assets of such
Person or to only a portion thereof) (other than any accounts payable or other
accrued current liability or obligation incurred in the ordinary course of
business in connection with the obtaining of materials or services), (b) all
reimbursement obligations and other liabilities (contingent or otherwise) of
such Person with respect to letters of credit, bank guarantees or bankers'
acceptances, (c) all obligations and liabilities (contingent or otherwise) of
such Person (i) in respect of leases of such Person required, in conformity with
GAAP, to be accounted for as capitalized lease obligations on the balance sheet
of such Person (as determined by the Company), or (ii) under any lease or
related document (including a purchase agreement, conditional sale or other
title retention agreement) in connection with the lease of real property or
improvement thereon (or any personal property included as part of any such
lease) which provides that such Person is contractually obligated to purchase or
cause a third party to purchase the leased property or pay an agreed upon
residual value of the leased property to the lessor (whether or not such lease
transaction is characterized as an operating lease or a capitalized lease in
accordance with GAAP), (d) all obligations (contingent or otherwise) of such
Person with respect to any interest rate or other swap, cap, floor or collar
agreement, hedge agreement, forward contract, or other similar instrument or
agreement or foreign currency hedge, exchange, purchase or similar instrument or
agreement; (e) all direct or indirect guaranties, agreements to be jointly
liable or similar agreements by such Person in respect of, and obligations or
liabilities of such Person to purchase or otherwise acquire or otherwise assure
a creditor against loss in respect of, indebtedness, obligations or liabilities
of another Person of the kind described in clauses (a) through (d), and (f) any
and all deferrals, renewals, extensions, refinancings and refundings of, or
amendments, modifications or supplements to, any indebtedness, obligation or
liability of the kind described in clauses (a) through (c).

     "Indenture" means this Indenture as amended or supplemented from time to
time pursuant to the terms of this Indenture.

     "Initial Purchasers" means Credit Suisse First Boston Corporation and UBS
Warburg LLC.

     "Issuance Date" means the date on which the Securities are first
authenticated and issued.

                                        3
<Page>

     "Officer" means the Chairman or any Co-Chairman of the Board, any Vice
Chairman of the Board, the Chief Executive Officer, the President, any Vice
President, the Chief Financial Officer, the Controller, the Secretary or any
Assistant Controller or Assistant Secretary of the Company.

     "Officers' Certificate" means a certificate signed by two Officers;
PROVIDED, HOWEVER, that for purposes of Sections 4.11 and 6.3, "Officers'
Certificate" means a certificate signed by the principal executive officer,
principal financial officer or principal accounting officer of the Company and
by one other Officer.

     "Opinion of Counsel" means a written opinion from legal counsel. The
counsel may be an employee of or counsel to the Company or the Trustee.

     "Person" or "person" means any individual, corporation, partnership,
limited liability company, joint venture, association, joint-stock company,
trust, unincorporated organization, government or any agency or political
subdivision thereof or any other entity.

     "Principal" or "principal" of a debt security, including the Securities,
means the principal of the security plus, when appropriate, the premium, if any,
on the security.

     "Redemption Date" when used with respect to any Security to be redeemed,
means the date fixed for such redemption pursuant to this Indenture.

     "Redemption Price" when used with respect to any Security to be redeemed,
means the price fixed for such redemption pursuant to this Indenture, as set
forth in the form of Security annexed as EXHIBIT A hereto.

     "Registration Rights Agreement" means the Registration Rights Agreement
dated, as of December 11, 2001, between the Company and the Initial Purchasers.

     "Representative" means the (a) indenture trustee or other trustee, agent or
representative for any Senior Indebtedness or (b) with respect to any Senior
Indebtedness that does not have any such trustee, agent or other representative,
(i) in the case of such Senior Indebtedness issued pursuant to an agreement
providing for voting arrangements as among the holders or owners of such Senior
Indebtedness, any holder or owner of such Senior Indebtedness acting with the
consent of the required persons necessary to bind such holders or owners of such
Senior Indebtedness and (ii) in the case of all other such Senior Indebtedness,
the holder or owner of such Senior Indebtedness.

     "Rule 144" means Rule 144 under the Securities Act or any successor to such
Rule.

     "Rule 144A" means Rule 144A under the Securities Act or any successor to
such Rule.

     "SEC" means the Securities and Exchange Commission.

     "Securities" means the 2 1/4% Convertible Subordinated Notes due 2006 or
any of them (each, a "Security"), as amended or supplemented from time to time,
that are issued under this Indenture.

     "Securities Act" means the Securities Act of 1933, as amended, and the
rules and regulations promulgated thereunder, as in effect from time to time.

     "Securities Custodian" means the Trustee, as custodian with respect to the
Securities in global form, or any successor thereto.

                                        4
<Page>

     "Senior Indebtedness" means the principal of, premium, if any, interest
(including all interest accruing subsequent to the commencement of any
bankruptcy or similar proceeding, whether or not a claim for post-petition
interest is allowed as a claim in any such proceeding) and rent payable on or in
connection with, and all fees, costs, expenses and other amounts accrued or due
on or in connection with, Indebtedness of the Company, whether outstanding on
the date of this Indenture or thereafter created, incurred, assumed, guaranteed
or in effect guaranteed by the Company (including all deferrals, renewals,
extensions or refundings of, or amendments, modifications or supplements to, the
foregoing), unless in the case of any particular Indebtedness the instrument
creating or evidencing the same or the assumption or guarantee thereof expressly
provides that such Indebtedness shall not be senior in right of payment to the
Securities or expressly provides that such Indebtedness is "pari passu" or
"junior" to the Securities. Notwithstanding the foregoing, the term Senior
Indebtedness shall not include (i) any Indebtedness of the Company to any
Subsidiary of the Company (other than Indebtedness of the Company to such
Subsidiary arising by reason of guarantees by the Company of Indebtedness of
such Subsidiary to a Person that is not a Subsidiary of the Company), (ii) the
Securities; (iii) Indebtedness of or amounts owed by the Company for
compensation to employees, or for goods or materials purchased in the ordinary
course of business, or for services; or (iv) the Company's 5 1/2% Convertible
Subordinated Notes due 2007. If any payment made to any holder of any Senior
Indebtedness or its Representative with respect to such Senior Indebtedness is
rescinded or must otherwise be returned by such holder or Representative upon
the insolvency, bankruptcy or reorganization of the Company or otherwise, the
reinstated Indebtedness of the Company arising as a result of such rescission or
return shall constitute Senior Indebtedness effective as of the date of such
rescission or return.

     "Significant Subsidiary" means, in respect of any Person, a Subsidiary of
such Person that would constitute a "significant subsidiary" as such term is
defined under Rule 1-02 of Regulation S-X under the Securities Act and the
Exchange Act.

     "Special Interest" has the meaning specified in paragraph 2 of the
Security.

     "Subsidiary" means, in respect of any Person, any corporation, association,
partnership or other business entity of which more than 50% of the total voting
power of shares of Capital Stock or other interests (including partnership
interests) entitled (without regard to the occurrence of any contingency) to
vote in the election of directors, managers, general partners or trustees
thereof is at the time owned or controlled, directly or indirectly, by (i) such
Person; (ii) such Person and one or more Subsidiaries of such Person; or (iii)
one or more Subsidiaries of such Person.

     "TIA" means the Trust Indenture Act of 1939, as amended, and the rules and
regulations thereunder as in effect on the date of this Indenture, except as
provided in Section 11.3, and except to the extent any amendment to the Trust
Indenture Act expressly provides for application of the Trust Indenture Act as
in effect on another date.

     "Trading Day" means, with respect to any security, each Monday, Tuesday,
Wednesday, Thursday and Friday, other than any day on which securities are not
generally traded on the principal exchange or market in which such security is
traded.

     "Transfer Restricted Global Security" means a Global Security that is a
Transfer Restricted Security.

     "Transfer Restricted Security" means a Security required to bear the
restricted legend set forth in the form of Security set forth in EXHIBIT A of
this Indenture.

                                        5
<Page>

     "Trustee" means the party named as such in the first paragraph of this
Indenture until a successor replaces it in accordance with the provisions of
this Indenture, and thereafter means the successor.

     "Trust Officer" means, with respect to the Trustee, any officer assigned to
the Corporate Trust Office, and also, with respect to a particular matter, any
other officer to whom such matter is referred because of such officer's
knowledge of and familiarity with the particular subject.

     "Unrestricted Certificated Security" means a Certificated Security that is
not a Transfer Restricted Security.

     "Unrestricted Global Security" means a Global Security that is not a
Transfer Restricted Security.

     "Vice President" when used with respect to the Company or the Trustee,
means any vice president, whether or not designated by a number or a word or
words added before or after the title "vice president."

     "Voting Stock" of a Person means all classes of Capital Stock or other
interests (including partnership interests) of such Person then outstanding and
normally entitled (without regard to the occurrence of any contingency) to vote
in the election of directors, managers or trustees thereof.

     SECTION 1.2. OTHER DEFINITIONS.

<Table>
<Caption>
                                           TERM                                                  DEFINED IN SECTION
---------------------------------------------------------------------------------------          ------------------
<S>                                                                                                       <C>
"Agent Members"........................................................................                    2.1(b)
"Bankruptcy Law".......................................................................                    8.1
"Change in Control"....................................................................                    3.8(a)
"Change in Control Purchase Date"......................................................                    3.8(c)
"Change in Control Purchase Notice"....................................................                    3.8(f)
"Change in Control Purchase Price".....................................................                    3.8(a)
"Closing Price"........................................................................                    4.6(d)
"Commencement Date"...................................................................                     3.8(c)
"Company Order"........................................................................                    2.2
"Conversion Agent".....................................................................                    2.3
"Conversion Date"......................................................................                    4.2
"Conversion Price".....................................................................                    4.6
"Current Market Price".................................................................                    4.6(d)
"Custodian"............................................................................                    8.1
"DTC"..................................................................................                    2.1
"Depositary"...........................................................................                    2.1
"Determination Date"...................................................................                    4.6(c)
"Event of Default".....................................................................                    8.1
"Expiration Date"......................................................................                    4.6(c)
"Expiration Time"......................................................................                    4.6(c)
"Legal Holiday"........................................................................                   12.7
"Legend" ..............................................................................                    2.12
"NNM"..................................................................................                    4.6(d)
"Offer Amount".........................................................................                    3.8(c)
</Table>

                                        6
<Page>

<Table>
<Caption>
                                           TERM                                                  DEFINED IN SECTION
---------------------------------------------------------------------------------------          ------------------
<S>                                                                                                       <C>
"Paying Agent".........................................................................                   2.3
"Payment Blockage Notice"..............................................................                   5.2
"Primary Registrar"....................................................................                   2.3
"Purchase Agreement"...................................................................                   2.1
"Purchase Offer".......................................................................                   3.8(a)
"Purchased Shares".....................................................................                   4.6(c)
"QIB"..................................................................................                   2.1
"Registrar"............................................................................                   2.3
"Rights Plan" .........................................................................                   4.6(c)
"Tender Period"........................................................................                   3.8(c)
"Triggering Distribution"..............................................................                   4.6(c)
"Trigger Event" .......................................................................                   4.6(c)
</Table>

     SECTION 1.3. TRUST INDENTURE ACT PROVISIONS.

     Whenever this Indenture refers to a provision of the TIA, that provision is
incorporated by reference in and made a part of this Indenture. The Indenture
shall also include those provisions of the TIA required to be included herein by
the provisions of the Trust Indenture Reform Act of 1990. The following TIA
terms used in this Indenture have the following meanings:

     "indenture securities" means the Securities;

     "indenture security holder" means a Securityholder;

     "indenture to be qualified" means this Indenture;

     "indenture trustee" or "institutional trustee" means the Trustee; and
"obligor" on the indenture securities means the Company or any other obligor on
the Securities.

     All other terms used in this Indenture that are defined in the TIA, defined
by TIA reference to another statute or defined by any SEC rule and not otherwise
defined herein have the meanings assigned to them therein.

     SECTION 1.4. RULES OF CONSTRUCTION.

     Unless the context otherwise requires:

          (A)  a term has the meaning assigned to it;

          (B)  an accounting term not otherwise defined has the meaning assigned
to it in accordance with GAAP;

          (C)  words in the singular include the plural, and words in the plural
include the singular;

          (D)  provisions apply to successive events and transactions;

                                        7
<Page>

          (E)  the term "merger" includes a statutory share exchange and the
term "merged" has a correlative meaning;

          (F)  the masculine gender includes the feminine and the neuter;

          (G)  references to agreements and other instruments include subsequent
amendments thereto; and

          (H)  "herein," "hereof" and other words of similar import refer to
this Indenture as a whole and not to any particular Article, Section or other
subdivision.

                                    ARTICLE 2
                                 THE SECURITIES

     SECTION 2.1. FORM AND DATING.

     The Securities and the Trustee's certificate of authentication shall be
substantially in the respective forms set forth in EXHIBIT A, which Exhibit is
incorporated in and made part of this Indenture. The Securities may have
notations, legends or endorsements required by law, stock exchange rule or
usage. The Company shall provide any such notations, legends or endorsements to
the Trustee in writing. Each Security shall be dated the date of its
authentication. The Securities are being offered and sold by the Company
pursuant to a Purchase Agreement, dated December 5, 2001 (the "Purchase
Agreement"), between the Company and the Initial Purchasers, in transactions
exempt from, or not subject to, the registration requirements of the Securities
Act.

     (a) RESTRICTED GLOBAL SECURITIES. All of the Securities are initially being
offered and sold to qualified institutional buyers as defined in Rule 144A
(collectively, "QIBs" or individually, each a "QIB") in reliance on Rule 144A
under the Securities Act and shall be issued initially in the form of one or
more Restricted Global Securities, which shall be deposited on behalf of the
purchasers of the Securities represented thereby with the Trustee, at its
Corporate Trust Office, as custodian for the depositary, The Depository Trust
Company ("DTC") (such depositary, or any successor thereto, being hereinafter
referred to as the "Depositary"), and registered in the name of its nominee,
Cede & Co., duly executed by the Company and authenticated by the Trustee as
hereinafter provided. The aggregate principal amount of the Restricted Global
Securities may from time to time be increased or decreased by adjustments made
on the records of the Securities Custodian as hereinafter provided, subject in
each case to compliance with the Applicable Procedures.

     (b) GLOBAL SECURITIES IN GENERAL. Each Global Security shall represent such
of the outstanding Securities as shall be specified therein and each shall
provide that it shall represent the aggregate amount of outstanding Securities
from time to time endorsed thereon and that the aggregate amount of outstanding
Securities represented thereby may from time to time be reduced or increased, as
appropriate, to reflect exchanges, redemptions, purchases or conversions of such
Securities. Any adjustment of the aggregate principal amount of a Global
Security to reflect the amount of any increase or decrease in the amount of
outstanding Securities represented thereby shall be made by the Trustee in
accordance with instructions given by the Holder thereof as required by Section
2.12 hereof and shall be made on the records of the Trustee and the Depositary.

                                        8
<Page>

     Members of, or participants in, the Depositary ("Agent Members") shall have
no rights under this Indenture with respect to any Global Security held on their
behalf by the Depositary or under the Global Security, and the Depositary
(including, for this purpose, its nominee) may be treated by the Company, the
Trustee and any agent of the Company or the Trustee as the absolute owner and
Holder of such Global Security for all purposes whatsoever. Notwithstanding the
foregoing, nothing herein shall (A) prevent the Company, the Trustee or any
agent of the Company or the Trustee from giving effect to any written
certification, proxy or other authorization furnished by the Depositary or (B)
impair, as between the Depositary and its Agent Members, the operation of
customary practices governing the exercise of the rights of a Holder of any
Security.

     (c) BOOK ENTRY PROVISIONS. The Company shall execute and the Trustee shall,
in accordance with this Section 2.1(c), authenticate and deliver initially one
or more Global Securities that (i) shall be registered in the name of the
Depositary, (ii) shall be delivered by the Trustee to the Depositary or pursuant
to the Depositary's instructions and (iii) shall bear legends substantially to
the following effect:

"UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (AND ANY PAYMENT HEREON IS MADE
TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY), ANY TRANSFER, PLEDGE OR OTHER
USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE
REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN. THIS SECURITY IS A
GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE HEREINAFTER REFERRED TO AND
IS REGISTERED IN THE NAME OF A DEPOSITARY OR A NOMINEE THEREOF. THIS SECURITY IS
EXCHANGEABLE FOR SECURITIES REGISTERED IN THE NAME OF A PERSON OTHER THAN THE
DEPOSITARY OR ITS NOMINEE ONLY IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE
INDENTURE AND, UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR
SECURITIES IN DEFINITIVE FORM, THIS SECURITY MAY NOT BE TRANSFERRED EXCEPT AS A
WHOLE BY THE DEPOSITARY TO A NOMINEE OF THE DEPOSITARY OR BY A NOMINEE OF THE
DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE DEPOSITARY OR BY THE
DEPOSITARY OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH
SUCCESSOR DEPOSITARY."

     SECTION 2.2. EXECUTION AND AUTHENTICATION.

     An Officer shall sign the Securities for the Company by manual or facsimile
signature attested by the manual or facsimile signature of the Secretary or an
Assistant Secretary of the Company. Typographic and other minor errors or
defects in any such facsimile signature shall not affect the validity or
enforceability of any Security which has been authenticated and delivered by the
Trustee.

     If an Officer whose signature is on a Security no longer holds that office
at the time the Trustee authenticates the Security, the Security shall be valid
nevertheless.

     A Security shall not be valid until an authorized signatory of the Trustee
manually signs the certificate of authentication on the Security. The signature
shall be conclusive evidence that the Security has been authenticated under this
Indenture.

                                        9
<Page>

     The Trustee shall authenticate and make available for delivery Securities
for original issue in the aggregate principal amount of up to $600,000,000 upon
receipt of a written order or orders of the Company signed by two Officers of
the Company (a "Company Order"). The Company Order shall specify the amount of
Securities to be authenticated, shall provide that all such Securities will be
represented by a Restricted Global Security and the date on which each original
issue of Securities is to be authenticated. The aggregate principal amount of
Securities outstanding at any time may not exceed $600,000,000 except as
provided in Section 2.7.

     The Trustee shall act as the initial authenticating agent. Thereafter, the
Trustee may appoint an authenticating agent acceptable to the Company to
authenticate Securities. An authenticating agent may authenticate Securities
whenever the Trustee may do so. Each reference in this Indenture to
authentication by the Trustee includes authentication by such agent. An
authenticating agent shall have the same rights as an Agent to deal with the
Company or an Affiliate of the Company.

     The Securities shall be issuable only in registered form without coupons
and only in denominations of $1,000 principal amount and any integral multiple
thereof.

     SECTION 2.3. REGISTRAR, PAYING AGENT AND CONVERSION AGENT.

     The Company shall maintain one or more offices or agencies where Securities
may be presented for registration of transfer or for exchange (each, a
"Registrar"), one or more offices or agencies where Securities may be presented
for payment (each, a "Paying Agent"), one or more offices or agencies where
Securities may be presented for conversion (each, a "Conversion Agent") and one
or more offices or agencies where notices and demands to or upon the Company in
respect of the Securities and this Indenture may be served. The Company will at
all times maintain a Paying Agent, Conversion Agent, Registrar and an office or
agency where notices and demands to or upon the Company in respect of the
Securities and this Indenture may be served in the Borough of Manhattan, The
City of New York. One of the Registrars (the "Primary Registrar") shall keep a
register of the Securities and of their transfer and exchange.

     The Company shall enter into an appropriate agency agreement with any Agent
not a party to this Indenture. The agreement shall implement the provisions of
this Indenture that relate to such Agent. The Company shall notify the Trustee
of the name and address of any Agent not a party to this Indenture. If the
Company fails to maintain a Registrar, Paying Agent, Conversion Agent or agent
for service of notices and demands in any place required by this Indenture, or
fails to give the foregoing notice, the Trustee shall act as such. The Company
or any Affiliate of the Company may act as Paying Agent (except for the purposes
of Section 6.1 and Article 10).

     The Company hereby initially designates the Trustee as Paying Agent,
Registrar, Custodian and Conversion Agent, and each of the Corporate Trust
Office of the Trustee and the office or agency of the Trustee in the Borough of
Manhattan, The City of New York (which shall initially be State Street Bank and
Trust Company, N.A., an Affiliate of the Trustee, as agent of the Trustee
located at 61 Broadway, New York, New York 10006, Attention: Corporate Trust
Administration (Invitrogen Corporation - 2 1/4% Convertible Subordinated Notes
due 2006)), one such office or agency of the Company for each of the aforesaid
purposes.

     SECTION 2.4. PAYING AGENT TO HOLD MONEY IN TRUST.

     Prior to 11:00 a.m., New York City time, on each due date of the principal
of or interest, if any, on any Securities, the Company shall deposit with a
Paying Agent a sum sufficient to pay such principal or

                                       10
<Page>

interest, if any, so becoming due. Subject to Section 5.2, a Paying Agent shall
hold in trust for the benefit of Securityholders or the Trustee all money held
by the Paying Agent for the payment of principal of or interest, if any, on the
Securities, and shall notify the Trustee of any default by the Company (or any
other obligor on the Securities) in making any such payment. If the Company or
an Affiliate of the Company acts as Paying Agent, it shall, before 11:00 a.m.,
New York City time, on each due date of the principal of or interest on any
Securities, segregate the money and hold it as a separate trust fund. The
Company at any time may require a Paying Agent to pay all money held by it to
the Trustee, and the Trustee may at any time during the continuance of any
default, upon written request to a Paying Agent, require such Paying Agent to
pay forthwith to the Trustee all sums so held in trust by such Paying Agent.
Upon doing so, the Paying Agent (other than the Company) shall have no further
liability for the money.

     SECTION 2.5. SECURITYHOLDER LISTS.

     The Trustee shall preserve in as current a form as is reasonably
practicable the most recent list available to it of the names and addresses of
Securityholders. If the Trustee is not the Primary Registrar, the Company shall
furnish to the Trustee on or before each semiannual interest payment date, and
at such other times as the Trustee may request in writing, a list in such form
and as of such date as the Trustee may reasonably require of the names and
addresses of Securityholders.

     SECTION 2.6. TRANSFER AND EXCHANGE.

     (a) Subject to compliance with any applicable additional requirements
contained in Section 2.12, when a Security is presented to a Registrar with a
request to register a transfer thereof or to exchange such Security for an equal
principal amount of Securities of other authorized denominations, the Registrar
shall register the transfer or make the exchange as requested; PROVIDED,
HOWEVER, that every Security presented or surrendered for registration of
transfer or exchange shall be duly endorsed or accompanied by an assignment form
and, if applicable, a transfer certificate each in the form included in EXHIBIT
A, and in form satisfactory to the Registrar duly executed by the Holder thereof
or its attorney duly authorized in writing. To permit registration of transfers
and exchanges, upon surrender of any Security for registration of transfer or
exchange at an office or agency maintained pursuant to Section 2.3, the Company
shall execute and the Trustee shall authenticate Securities of a like aggregate
principal amount at the Registrar's request. Any exchange or transfer shall be
without charge, except that the Company or the Registrar may require payment of
a sum sufficient to cover any tax or other governmental charge that may be
imposed in relation thereto, and PROVIDED, THAT this sentence shall not apply to
any exchange pursuant to Section 2.10, 2.12(a), 3.6, 3.11, 4.2 (last paragraph)
or 11.5.

     Neither the Company, any Registrar nor the Trustee shall be required to
exchange or register a transfer of (i) any Securities for a period of 15 days
next preceding any mailing of a notice of Securities to be redeemed, (ii) any
Securities or portions thereof selected or called for redemption (except, in the
case of redemption of a Security in part, the portion thereof not to be
redeemed) or (iii) any Securities or portions thereof in respect of which a
Change in Control Purchase Notice has been delivered and not withdrawn by the
Holder thereof (except, in the case of the purchase of a Security in part, the
portion thereof not to be purchased).

     All Securities issued upon any transfer or exchange of Securities shall be
valid obligations of the Company, evidencing the same debt and entitled to the
same benefits under this Indenture, as the Securities surrendered upon such
transfer or exchange.

                                       11
<Page>

     (b) Any Registrar appointed pursuant to Section 2.3 hereof shall provide to
the Trustee such information as the Trustee may reasonably require in connection
with the delivery by such Registrar of Securities upon transfer or exchange of
Securities.

     (c) Each Holder of a Security agrees to indemnify the Company and the
Trustee against any liability that may result from the transfer, exchange or
assignment of such Holder's Security in violation of any provision of this
Indenture and/or applicable United States federal or state securities law.

     The Trustee shall have no obligation or duty to monitor, determine or
inquire as to compliance with any restrictions on transfer imposed under this
Indenture or under applicable law with respect to any transfer of any interest
in any Security (including any transfers between or among Agent Members or other
beneficial owners of interests in any Global Security) other than to require
delivery of such certificates and other documentation or evidence as are
expressly required by, and to do so if and when expressly required by the terms
of, this Indenture, and to examine the same to determine substantial compliance
as to form with the express requirements hereof.

     SECTION 2.7. REPLACEMENT SECURITIES.

     If any mutilated Security is surrendered to the Company, a Registrar or the
Trustee, or the Company, a Registrar and the Trustee receive evidence to their
satisfaction of the destruction, loss or theft of any Security, and there is
delivered to the Company, the applicable Registrar and the Trustee such security
or indemnity as will be required by them to save each of them harmless, then, in
the absence of notice to the Company, such Registrar or the Trustee that such
Security has been acquired by a bona fide purchaser, the Company shall execute,
and upon its written request the Trustee shall authenticate and deliver, in
exchange for any such mutilated Security or in lieu of any such destroyed, lost
or stolen Security, a new Security of like tenor and principal amount, bearing a
number not contemporaneously outstanding.

     In case any such mutilated, destroyed, lost or stolen Security has become
or is about to become due and payable, or is about to be redeemed or purchased
by the Company pursuant to Article 3, the Company in its discretion may, instead
of issuing a new Security, pay, redeem or purchase such Security, as the case
may be.

     Upon the issuance of any new Securities under this Section 2.7, the Company
may require the payment of a sum sufficient to cover any tax or other
governmental charge that may be imposed in relation thereto and any other
reasonable expenses (including the reasonable fees and expenses of the Trustee
or the Registrar) in connection therewith.

     Every new Security issued pursuant to this Section 2.7 in lieu of any
mutilated, destroyed, lost or stolen Security shall constitute an original
additional contractual obligation of the Company, whether or not the mutilated,
destroyed, lost or stolen Security shall be at any time enforceable by anyone,
and shall be entitled to all benefits of this Indenture equally and
proportionately with any and all other Securities duly issued hereunder.

     The provisions of this Section 2.7 are (to the extent lawful) exclusive and
shall preclude (to the extent lawful) all other rights and remedies with respect
to the replacement or payment of mutilated, destroyed, lost or stolen
Securities.

                                       12
<Page>

     SECTION 2.8. OUTSTANDING SECURITIES.

     Securities outstanding at any time are all Securities authenticated by the
Trustee, except for those canceled by it, those converted pursuant to Article
IV, those delivered to it for cancellation or surrendered for transfer or
exchange and those described in this Section 2.8 as not outstanding.

     If a Security is replaced pursuant to Section 2.7, it ceases to be
outstanding unless the Company receives proof satisfactory to it that the
replaced Security is held by a bona fide purchaser.

     If a Paying Agent (other than the Company or an Affiliate of the Company)
holds on a Redemption Date, a Change in Control Purchase Date or the Final
Maturity Date money sufficient to pay the principal of (including premium, if
any) and accrued interest on Securities (or portions thereof) payable on that
date, then on and after such Redemption Date, Change in Control Purchase Date or
the final Maturity Date, as the case may be, such Securities (or portions
thereof, as the case may be) shall cease to be outstanding and interest on them
shall cease to accrue; provided, that if such Securities are to be redeemed,
notice of such redemption has been duly given pursuant to this Indenture or
provision therefore satisfactory to the Trustee has been made.

     Subject to the restrictions contained in Section 2.9, a Security does not
cease to be outstanding because the Company or an Affiliate of the Company holds
the Security.

     SECTION 2.9. TREASURY SECURITIES.

     In determining whether the Holders of the required principal amount of
Securities have concurred in any notice, direction, waiver or consent,
Securities owned by the Company or any other obligor on the Securities or by any
Affiliate of the Company or of such other obligor shall be disregarded, except
that, for purposes of determining whether the Trustee shall be protected in
relying on any such notice, direction, waiver or consent, only Securities which
a Trust Officer of the Trustee actually knows are so owned shall be so
disregarded. Securities so owned which have been pledged in good faith shall not
be disregarded if the pledgee establishes to the satisfaction of the Trustee the
pledgee's right so to act with respect to the Securities and that the pledgee is
not the Company or any other obligor on the Securities or any Affiliate of the
Company or of such other obligor.

     SECTION 2.10. TEMPORARY SECURITIES.

     Until definitive Securities are ready for delivery, the Company may prepare
and execute, and, upon receipt of a Company Order, the Trustee shall
authenticate and deliver, temporary Securities. Temporary Securities shall be
substantially in the form of definitive Securities but may have variations that
the Company with the consent of the Trustee considers appropriate for temporary
Securities. Without unreasonable delay, the Company shall prepare and the
Trustee shall authenticate and deliver definitive Securities in exchange for
temporary Securities.

     SECTION 2.11. CANCELLATION.

     The Company at any time may deliver Securities to the Trustee for
cancellation. The Registrar, the Paying Agent and the Conversion Agent shall
forward to the Trustee or its agent any Securities surrendered to them for
transfer, exchange, redemption, payment or conversion. The Trustee and no one
else shall cancel, in accordance with its standard procedures, all Securities
surrendered for transfer, exchange, redemption, payment, conversion or
cancellation and shall deliver the canceled Securities to the Company. All
Securities which are redeemed, purchased or otherwise acquired by the Company or
any of its Subsidiaries prior to the

                                       13
<Page>

Final Maturity Date shall be delivered to the Trustee for cancellation, and the
Company may not hold or resell such Securities or issue any new Securities to
replace any such Securities or any Securities that any Holder has converted
pursuant to Article 4. Without limitation to the foregoing, any Securities
acquired by any investment bankers or other purchasers pursuant to Section 3.7
shall be surrendered for conversion and thereafter cancelled, and may not be
reoffered, sold or otherwise transferred.

     SECTION 2.12. LEGEND; ADDITIONAL TRANSFER AND EXCHANGE REQUIREMENTS.

     (a) If Securities are issued upon the transfer, exchange or replacement of
Securities subject to restrictions on transfer and bearing the legends set forth
on the forms of Securities attached hereto as EXHIBIT A (collectively, the
"Legend"), or if a request is made to remove the Legend on a Security, the
Securities so issued shall bear the Legend, or the Legend shall not be removed,
as the case may be, unless there is delivered to the Company and the Registrar
such satisfactory evidence, which shall include an opinion of counsel if
requested by the Company or such Registrar, as may be reasonably required by the
Company and the Registrar, that neither the Legend nor the restrictions on
transfer set forth therein are required to ensure that transfers thereof comply
with the provisions of Rule 144A or Rule 144 under the Securities Act or that
such Securities are not "restricted" within the meaning of Rule 144 under the
Securities Act; PROVIDED THAT no such evidence need be supplied in connection
with the sale of such Security pursuant to a registration statement that is
effective at the time of such sale. Upon (i) provision of such satisfactory
evidence if requested, or (ii) notification by the Company to the Trustee and
Registrar of the sale of such Security pursuant to a registration statement that
is effective at the time of such sale, the Trustee, at the written direction of
the Company, shall authenticate and deliver a Security that does not bear the
Legend. If the Legend is removed from the face of a Security and the Security is
subsequently held by an Affiliate of the Company, the Legend shall be
reinstated.

     (b) A Global Security may not be transferred, in whole or in part, to any
Person other than the Depositary or a nominee or any successor thereof, and no
such transfer to any such other Person may be registered; PROVIDED THAT the
foregoing shall not prohibit any transfer of a Security that is issued in
exchange for a Global Security but is not itself a Global Security. No transfer
of a Security to any Person shall be effective under this Indenture or the
Securities unless and until such Security has been registered in the name of
such Person. Notwithstanding any other provisions of this Indenture or the
Securities, transfers of a Global Security, in whole or in part, shall be made
only in accordance with this Section 2.12.

     (c) Subject to the succeeding paragraph, every Security shall be subject to
the restrictions on transfer provided in the Legend other than a Restricted
Global Security. Whenever any Transfer Restricted Security other than a
Restricted Global Security is presented or surrendered for registration of
transfer or for exchange for a Security registered in a name other than that of
the Holder, such Security must be accompanied by a certificate in substantially
the form set forth in EXHIBIT B, dated the date of such surrender and signed by
the Holder of such Security, as to compliance with such restrictions on
transfer. The Registrar shall not be required to accept for such registration of
transfer or exchange any Security not so accompanied by a properly completed
certificate.

     (d) The restrictions imposed by the Legend upon the transferability of any
Security shall cease and terminate when such Security has been sold pursuant to
an effective registration statement under the Securities Act or transferred in
compliance with Rule 144 under the Securities Act (or any successor provision
thereto) or, if earlier, upon the expiration of the holding period applicable to
sales thereof under Rule 144(k) under the Securities Act (or any successor
provision). Any Security as to which such restrictions

                                       14
<Page>

on transfer shall have expired in accordance with their terms or shall have
terminated may, upon a surrender of such Security for exchange to the Registrar
in accordance with the provisions of this Section 2.12 (accompanied, in the
event that such restrictions on transfer have terminated by reason of a transfer
in compliance with Rule 144 or any successor provision, by, if requested, an
opinion of counsel reasonably acceptable to the Company, addressed to the
Company and in form acceptable to the Company, to the effect that the transfer
of such Security has been made in compliance with Rule 144 or such successor
provision), be exchanged for a new Security, of like tenor and aggregate
principal amount, which shall not bear the restrictive Legend. The Company shall
inform the Trustee of the effective date of any registration statement
registering the Securities under the Securities Act. The Trustee shall not be
liable for any action taken or omitted to be taken by it in good faith in
accordance with the aforementioned opinion of counsel or registration statement.

     (e) As used in the preceding two paragraphs of this Section 2.12, the term
"transfer" encompasses any sale, pledge, transfer, hypothecation or other
disposition of any Security.

     (f) The provisions of clauses (i), (ii), (iii) and (iv) below shall apply
only to Global Securities:

               (i) Notwithstanding any other provisions of this Indenture or the
          Securities, a Global Security shall not be exchanged in whole or in
          part for a Security registered in the name of any Person other than
          the Depositary or one or more nominees thereof, PROVIDED THAT a Global
          Security may be exchanged for Securities registered in the names of
          any person designated by the Depositary in the event that (A) the
          Depositary has notified the Company that it is unwilling or unable to
          continue as Depositary for such Global Security or such Depositary has
          ceased to be a "clearing agency" registered under the Exchange Act,
          and a successor Depositary is not appointed by the Company within 90
          days, (B) the Company has provided the Depositary with written notice
          that it has decided to discontinue use of the system of book-entry
          transfer through the Depositary or any successor Depositary or (C) an
          Event of Default has occurred and is continuing with respect to the
          Securities. Any Global Security exchanged pursuant to clauses (A) or
          (B) above shall be so exchanged in whole and not in part, and any
          Global Security exchanged pursuant to clause (C) above may be
          exchanged in whole or from time to time in part as directed by the
          Depositary. Any Security issued in exchange for a Global Security or
          any portion thereof shall be a Global Security; provided that any such
          Security so issued that is registered in the name of a Person other
          than the Depositary or a nominee thereof shall not be a Global
          Security.

               (ii) Securities issued in exchange for a Global Security or any
          portion thereof shall be issued in definitive, fully-registered book
          entry form, without interest coupons, shall have an aggregate
          principal amount equal to that of such Global Security or portion
          thereof to be so exchanged, shall be registered in such names and be
          in such authorized denominations as the Depositary shall designate and
          shall bear the applicable legends provided for herein. Any Global
          Security to be exchanged in whole shall be surrendered by the
          Depositary to the Trustee, as Registrar. With regard to any Global
          Security to be exchanged in part, either such Global Security shall be
          so surrendered for exchange or, if the Trustee is acting as custodian
          for the Depositary or its nominee with respect to such Global
          Security, the principal amount thereof shall be reduced, by an amount
          equal to the portion thereof to be so exchanged, by means of an
          appropriate adjustment made on the records of the Trustee. Upon any
          such surrender or adjustment, the Trustee shall authenticate and
          deliver the Security issuable on such exchange to or upon the order of
          the Depositary or an authorized representative thereof.

                                       15
<Page>

               (iii) Subject  to  the  provisions  of  clause  (v)  below,   the
registered  Holder  may  grant  proxies  and  otherwise  authorize  any  Person,
including  Agent  Members  and persons  that may hold  interests  through  Agent
Members,  to take any  action  which a Holder is  entitled  to take  under  this
Indenture or the Securities.

               (iv)  In the  event  of  the  occurrence  of  any  of the  events
specified in clause (i) above,  the Company will promptly make  available to the
Trustee a reasonable  supply of  Certificated  Securities in  definitive,  fully
registered form, without interest coupons.

               (v)   Neither Agent Members nor any other Persons on whose behalf
Agent Members may act shall have any rights under this Indenture with respect to
any Global  Security  registered  in the name of the  Depositary  or any nominee
thereof, or under any such Global Security,  and the Depositary or such nominee,
as the case may be, may be treated by the Company,  the Trustee and any agent of
the  Company or the  Trustee  as the  absolute  owner and holder of such  Global
Security for all purposes  whatsoever.  Notwithstanding  the foregoing,  nothing
herein shall prevent the Company, the Trustee or any agent of the Company or the
Trustee  from  giving  effect  to any  written  certification,  proxy  or  other
authorization  furnished by the Depositary or such nominee,  as the case may be,
or impair, as between the Depositary,  its Agent Members and any other person on
whose behalf an Agent Member may act,  the  operation of customary  practices of
such Persons governing the exercise of the rights of a holder of any Security.

     SECTION 2.13. CUSIP NUMBERS.

     The Company in issuing the Securities may use one or more "CUSIP" numbers
(if then generally in use), and, if so, the Trustee shall use "CUSIP" numbers in
notices of redemption or purchase as a convenience to Holders; PROVIDED THAT any
such notice may state that no representation is made as to the correctness of
such numbers either as printed on the Securities or as contained in any notice
of a redemption or purchase and that reliance may be placed only on the other
identification numbers printed on the Securities, and any such redemption or
purchase shall not be affected by any defect in or omission of such numbers. The
Company will promptly notify the Trustee of any change in the "CUSIP" numbers.

                                    ARTICLE 3
                            REDEMPTION AND PURCHASES

     SECTION 3.1. RIGHT TO REDEEM; NOTICE TO TRUSTEE.

     The Securities may be redeemed at the election of the Company, as a whole
or from time to time in part, at any time on or after December 20, 2005, at the
Redemption Price specified in paragraph 6 of the form of Security attached
hereto as EXHIBIT A, together with accrued interest up to, but not including,
the Redemption Date; PROVIDED THAT if the Redemption Date falls after an
interest payment record date and on or before an interest payment date, then the
interest will be payable to the Holders in whose name the Securities are
registered at the close of business on the interest payment record date.

     If the Company elects to redeem Securities pursuant to this Section 3.1 and
paragraph 6 of the Securities, it shall notify the Trustee at least 45 days
prior to the Redemption Date as fixed by the Company (unless a shorter notice
shall be satisfactory to the Trustee) of the Redemption Date and the principal
amount of Securities to be redeemed. If fewer than all of the Securities are to
be redeemed, the record date relating to

                                       16
<Page>

such redemption shall be selected by the Company and given to the Trustee, which
record date shall not be less than ten days after the date of notice to the
Trustee.

     SECTION 3.2. SELECTION OF SECURITIES TO BE REDEEMED.

     If less than all of the Securities are to be redeemed, unless the
procedures of the Depositary provide otherwise, the Trustee shall, at least 20
days but not more than 60 days prior to the Redemption Date, select the
Securities to be redeemed. The Trustee shall make the selection from the
Securities outstanding and not previously called for redemption, by lot, or in
its discretion, on a pro rata basis. Securities in denominations of $1,000 may
only be redeemed in whole. The Trustee may select for redemption portions (equal
to $1,000 or any integral multiple thereof) of the principal of Securities that
have denominations larger than $1,000. Provisions of this Indenture that apply
to Securities called for redemption also apply to portions of Securities called
for redemption.

     If any Security selected for partial redemption is converted in part before
termination of the conversion right with respect to the portion of the Security
so selected, the converted portion of such Security shall be deemed to be the
portion selected for redemption. Securities which have been converted during a
selection of Securities to be redeemed shall be treated by the Trustee as
outstanding for the purpose of such selection.

     SECTION 3.3. NOTICE OF REDEMPTION.

     At least 20 days but not more than 60 days before a Redemption Date, the
Company shall mail or cause to be mailed a notice of redemption to each Holder
of Securities to be redeemed at such Holder's address as it appears on the
Primary Registrar's books.

     The notice shall identify the Securities (including CUSIP numbers) to be
redeemed and shall state:

          (1) the Redemption Date;

          (2) the Redemption Price;

          (3) the then current Conversion Price;

          (4) the name and address of each Paying Agent and Conversion Agent;

          (5) that Securities called for redemption must be presented and
surrendered to a Paying Agent to collect the Redemption Price;

          (6) that Holders who wish to convert Securities must surrender such
Securities for conversion no later than the close of business on the Business
Day immediately preceding the Redemption Date and must satisfy the other
requirements set forth in paragraph 9 of the Securities;

          (7) that, unless the Company defaults in making the payment of the
Redemption Price, interest on Securities called for redemption shall cease
accruing on and after the Redemption Date and the only remaining right of the
Holder shall be to receive payment of the Redemption Price plus accrued
interest, if any upon presentation and surrender to a Paying Agent of the
Securities; and

                                       17
<Page>

          (8) if any Security is being redeemed in part, the portion of the
principal amount of such Security to be redeemed and that, after the Redemption
Date, upon presentation and surrender of such Security, a new Security or
Securities in aggregate principal amount equal to the unredeemed portion thereof
will be issued.

     If any of the Securities to be redeemed is in the form of a Global
Security, then the Company shall modify such notice to the extent necessary to
accord with the procedures of the Depositary applicable to redemptions. At the
Company's written request, which request shall (i) be irrevocable once given and
(ii) set forth all relevant information required by clauses (1) through (8) of
the preceding paragraph, the Trustee shall give the notice of redemption in the
Company's name and at the Company's expense.

     SECTION 3.4. EFFECT OF NOTICE OF REDEMPTION.

     Once notice of redemption is mailed, Securities called for redemption
become due and payable on the Redemption Date and at the Redemption Price stated
in the notice, together with accrued interest, if any, except for Securities
that are converted in accordance with the provisions of Article 4. Upon
presentation and surrender to a Paying Agent, Securities called for redemption
shall be paid at the Redemption Price, plus accrued interest up to but not
including the Redemption Date; PROVIDED THAT if the Redemption Date falls after
an interest payment record date and on or before an interest payment date, then
the interest will be payable to the Holders in whose name the Securities are
registered at the close of business on the interest payment record date.

     SECTION 3.5. DEPOSIT OF REDEMPTION PRICE.

     Prior to 11:00 a.m. New York City time, on the Redemption Date, the Company
shall deposit with a Paying Agent (or, if the Company acts as Paying Agent,
shall segregate and hold in trust) an amount of money (in immediately available
funds if deposited on such Redemption Date) sufficient to pay the Redemption
Price of and accrued interest on all Securities to be redeemed on that date,
other than Securities or portions thereof called for redemption on that date
which have been delivered by the Company to the Trustee for cancellation or have
been converted. The Paying Agent shall as promptly as practicable return to the
Company any money not required for that purpose because of the conversion of
Securities pursuant to Article 4 or, if such money is then held by the Company
in trust and is not required for such purpose, it shall be discharged from the
trust.

     SECTION 3.6. SECURITIES REDEEMED IN PART.

     Upon presentation and surrender of a Security that is redeemed in part, the
Company shall execute and the Trustee shall authenticate and deliver to the
Holder a new Security equal in principal amount to the unredeemed portion of the
Security surrendered.

     SECTION 3.7. CONVERSION ARRANGEMENT ON CALL FOR REDEMPTION.

     In connection with any redemption of Securities, the Company may arrange
for the purchase and conversion of any Securities called for redemption by an
agreement with one or more investment bankers or other purchasers to purchase
such Securities by paying to a Paying Agent (other than the Company or any of
its Affiliates) in trust for the Holders, on or before 11:00 a.m. New York City
time on the Redemption Date, an amount that, together with any amounts deposited
with such Paying Agent by the Company for the redemption of such Securities, is
not less than the Redemption Price, together with interest accrued to, but not

                                       18
<Page>

including, the Redemption Date, of such Securities. Notwithstanding anything to
the contrary contained in this Article 3, the obligation of the Company to pay
the Redemption Price of such Securities, including all accrued interest, shall
be deemed to be satisfied and discharged to the extent such amount is so paid by
such purchasers; PROVIDED, HOWEVER, that nothing in this Section 3.7 shall
relieve the Company of its obligation to pay the Redemption Price, plus accrued
interest to but excluding the relevant Redemption Date, on Securities called for
redemption. If such an agreement with one or more investment banks or other
purchasers is entered into, any Securities called for redemption and not
surrendered for conversion by the Holders thereof prior to the relevant
Redemption Date may, at the option of the Company upon written notice to the
Trustee, be deemed, to the fullest extent permitted by law, acquired by such
purchasers from such Holders and (notwithstanding anything to the contrary
contained in Article 4) surrendered by such purchasers for conversion, all as of
11:00 a.m. New York City time on the Redemption Date, subject to payment of the
above amount as aforesaid. The Paying Agent shall hold and pay to the Holders
whose Securities are selected for redemption any such amount paid to it for
purchase in the same manner as it would money deposited with it by the Company
for the redemption of Securities. Without the Paying Agent's prior written
consent, no arrangement between the Company and such purchasers for the purchase
and conversion of any Securities shall increase or otherwise affect any of the
powers, duties, responsibilities or obligations of the Paying Agent as set forth
in this Indenture, and the Company agrees to indemnify the Paying Agent from,
and hold it harmless against, any loss, liability or expense arising out of or
in connection with any such arrangement for the purchase and conversion of any
Securities between the Company and such purchasers, including the costs and
expenses incurred by the Paying Agent in the defense of any claim or liability
arising out of or in connection with the exercise or performance of any of its
powers, duties, responsibilities or obligations under this Indenture.

     SECTION 3.8. PURCHASE OF SECURITIES AT OPTION OF THE HOLDER UPON CHANGE IN
CONTROL.

     (a) If at any time that Securities remain outstanding there shall occur a
Change in Control, Securities shall be purchased by the Company at the option of
the Holders (equal to $1,000 or an integral multiple thereof) pursuant to the
offer to all Holders of the Securities to purchase the Securities (the "Purchase
Offer") at a purchase price equal to 100% of the principal amount of the
Securities, together with accrued and unpaid interest to, but excluding, the
Change in Control Purchase Date (the "Change of Control Purchase Price").

     A "Change in Control" shall be deemed to have occurred if any of the
following occurs after the date hereof:

          (1) any "Person" or "group," (as such terms are defined below) within
the meaning of Sections 13(d) and 14(d)(2) of the Exchange Act or any successor
provision to either of the foregoing, including any group acting for the purpose
of acquiring, holding or disposing of securities within the meaning of Rule
13d-5(b)(1) under the Exchange Act, becomes the "beneficial owner", as defined
in Rule 13d-3 under the Exchange Act, of more than 50% of the total voting power
of all classes of the Company's voting stock and/or warrants or options to
acquire such voting stock, calculated on a fully diluted basis;

          (2) the sale, lease, transfer, conveyance or other disposition, in one
or a series of related transactions, of all or substantially all of the
properties or assets of the Company to any "Person" or "group," within the
meaning of Sections 13(d)(3) and 14(d)(2) of the Exchange Act or any successor
provision to

                                       19
<Page>

either of the foregoing, including any group acting for the purpose of
acquiring, holding or disposing of securities within the meaning of Rule
13d-5(b)(1) under the Exchange Act;

          (3) the approval by the requisite stockholders of the Company of a
plan of liquidation or dissolution of the Company; or

          (4) the first day on which a majority of the members of the Company's
Board of Directors are not Continuing Directors.

     (b) Within 25 days following any Change of Control, the Company shall mail
to each Holder the Purchase Offer as described herein.

     (c) The Purchase Offer shall remain open for a period specified by the
Company which shall be no less than 30 calendar days and no more than 45
calendar days following its commencement (the "Commencement Date") (as
determined in accordance with this Section 3.8 herein), except to the extent
that a longer period is required by applicable law (the "Tender Period"). Upon
the expiration of the Tender Period (the "Change in Control Purchase Date"), the
Company shall purchase the principal amount of all of the Securities required to
be purchased pursuant to this Section 3.8 (the "Offer Amount").

     (d) If the Change in Control Purchase Date is on or after an interest
payment record date and on or before the related interest payment date, any
accrued interest shall be paid to the Person in whose name a Security is
registered at the close of business on such record date, and no Special Interest
will be payable to Holders who tender Securities pursuant to the Purchase Offer.

     (e) The Company shall provide the Trustee with notice of the Purchase Offer
at least 10 days before the Commencement Date.

     (f) On or before the Commencement Date, the Company or the Trustee (at the
expense of the Company) shall send, by first class mail, a notice to each of the
Holders, which shall govern the terms of the Purchase Offer and shall state:

          (1) that the Purchase Offer is being made pursuant to this Section 3.8
hereof, that all Securities validly tendered will be accepted for payment and
the length of time the Purchase Offer will remain open;

          (2) the Change in Control Purchase Price and the Change in Control
Purchase Date, and that all Securities tendered will be accepted for payment;

          (3) that any Securities or portion thereof not tendered or accepted
for payment will continue to accrue interest;

          (4) that, unless the Company defaults in the payment of the Change in
Control Purchase Price, any Securities or portion thereof accepted for payment
pursuant to the Purchase Offer will cease to accrue interest after the Change in
Control Purchase Date;

          (5) that Holders electing to have a Securities or portion thereof
purchased pursuant to any Purchase Offer will be required to surrender the
Securities, with the form entitled "Change in Control Purchase Notice" on the
reverse of the Securities completed, to the Company, a depositary, if appointed
by

                                       20
<Page>

the Company, or a Paying Agent at the address specified in the notice prior
to the close of business on the third Business Day preceding the Change in
Control Purchase Date;

          (6) that Holders will be entitled to withdraw their election if the
Company, Depositary or Paying Agent, as the case may be, receives, not later
than the close of business on the second Business Day preceding the Change in
Control Purchase Date, or such longer period as may be required by law, a letter
or a telegram, telex or facsimile transmission (receipt of which is confirmed
and promptly followed by a letter) setting forth the name of the Holder, the
principal amount of the Security or portion thereof the Holder delivered for
purchase and a statement that such Holder is withdrawing his election to have
the Security or portion thereof purchased;

          (7) that Holders whose Securities were purchased only in part will be
issued new Securities equal in principal amount to the unpurchased portion of
the Securities surrendered; and

          (8) the "CUSIP" number of the Securities to be purchased.

     (g) On or prior to the Change in Control Purchase Date, the Company shall
irrevocably deposit with the Trustee or a Paying Agent in immediately available
funds an amount equal to the Offer Amount to be held for payment in accordance
with the terms of this Section 3.8. On the Change in Control Purchase Date, the
Company shall, to the extent lawful, (i) accept for payment the Securities or
portions thereof properly tendered pursuant to the Purchase Offer, (ii) deliver
or cause the Depositary or Paying Agent to deliver to the Trustee Securities so
accepted and (iii) deliver to the Trustee an Officers' Certificate stating such
Securities or portions thereof have been accepted for payment by the Company in
accordance with the terms of this Section 3.8. The Depositary, the Paying Agent
or the Company, as the case may be, shall promptly (but in any case not later
than ten (10) calendar days after the Change in Control Purchase Date) mail or
deliver to each tendering Holder an amount equal to the Change in Control
Purchase Price of the Securities tendered by such Holder and accepted by the
Company for purchase, and the Trustee shall promptly authenticate and mail or
deliver to such Holders a new Security equal in principal amount to any
unpurchased portion of the Securities surrendered. Any Securities not so
accepted shall be promptly mailed or delivered by or on behalf of the Company to
the Holder thereof. The Company will publicly announce in a newspaper of general
circulation the results of the Purchase Offer on or as soon as practicable after
the Change in Control Purchase Date.

     (h) The Purchase Offer shall be made by the Company in compliance with all
applicable provisions of the Exchange Act, and all applicable tender offer rules
promulgated thereunder, and shall include all instructions and materials
necessary to enable such Holders to tender their Securities.

     SECTION 3.9. COMPLIANCE WITH SECURITIES LAWS UPON PURCHASE OF SECURITIES.

     In connection with any offer to purchase or purchase of Securities under
Section 3.8, the Company shall (a) comply with Rule 13e-4 and Rule 14e-1 (or any
successor to either such Rule), if applicable, under the Exchange Act, (b) file
the related Schedule TO (or any successor or similar schedule, form or report)
if required under the Exchange Act, and (c) otherwise comply with all federal
and state securities laws in connection with such offer to purchase or purchase
of Securities, all so as to permit the rights of the Holders and obligations of
the Company under Sections 3.8 to be exercised in the time and in the manner
specified therein.

                                       21
<Page>

     SECTION 3.10. REPAYMENT TO THE COMPANY.

     To the extent that the aggregate amount of cash deposited by the Company
pursuant to Section 3.8 (g) exceeds the aggregate Change in Control Purchase
Price, thereon of the Securities or portions thereof that the Company is
obligated to purchase, then promptly after the Change in Control Purchase Date
the Trustee or a Paying Agent, as the case may be, shall return any such excess
cash to the Company.

                                    ARTICLE 4
                                   CONVERSION

     SECTION 4.1. CONVERSION PRIVILEGE.

     Subject to the further provisions of this Article 4 and paragraph 9 of the
Securities, a Holder of a Security may convert the principal amount of such
Security (or any portion thereof equal to $1,000 or any integral multiple of
$1,000 in excess thereof) into Common Stock at any time prior to the close of
business on the Final Maturity Date, at the Conversion Price then in effect;
PROVIDED, HOWEVER, that, if such Security is called for redemption or submitted
or presented for purchase pursuant to Article 3, such conversion right shall
terminate at the close of business on the Business Day immediately preceding the
Redemption Date or Change in Control Purchase Date, as the case may be, for such
Security or such earlier date as the Holder presents such Security for
redemption or for purchase (unless the Company shall default in making the
redemption payment or Change in Control Purchase Price payment when due, in
which case the conversion right shall terminate at the close of business on the
date such default is cured and such Security is redeemed or purchased, as the
case may be). The number of shares of Common Stock issuable upon conversion of a
Security shall be determined by dividing the principal amount of the Security or
portion thereof surrendered for conversion by the Conversion Price in effect on
the Conversion Date. The initial Conversion Price is set forth in paragraph 9 of
the Securities and is subject to adjustment as provided in this Article 4.

     Provisions of this Indenture that apply to conversion of all of a Security
also apply to conversion of a portion of a Security.

     A Security in respect of which a Holder has delivered a Change in Control
Purchase Notice pursuant to Section 3.8 exercising the option of such Holder to
require the Company to purchase such Security may be converted only if such
Change in Control Purchase Notice is withdrawn by a written notice of withdrawal
delivered to a Paying Agent prior to the close of business on the Business Day
immediately preceding the Change in Control Purchase Date in accordance with
Section 3.9.

     A Holder of Securities is not entitled to any rights of a holder of Common
Stock until such Holder has converted its Securities to Common Stock, and only
to the extent such Securities are deemed to have been converted into Common
Stock pursuant to this Article 4.

     SECTION 4.2. CONVERSION PROCEDURE.

     To convert a Security, a Holder must (a) complete and manually sign the
conversion notice on the back of the Security and deliver such notice to a
Conversion Agent, (b) surrender the Security to a Conversion Agent, (c) furnish
appropriate endorsements and transfer documents if required by a Registrar or a
Conversion Agent, and (d) pay any transfer or similar tax, if required. The date
on which the Holder satisfies all of those requirements is the "Conversion
Date." As soon as practicable after the Conversion Date, the Company shall
deliver to the Holder through a Conversion Agent a certificate for the number of
whole shares

                                       22
<Page>

of Common Stock issuable upon the conversion and cash in lieu of any fractional
shares pursuant to Section 4.3. Anything herein to the contrary notwithstanding,
in the case of Global Securities, conversion notices may be delivered and such
Securities may be surrendered for conversion in accordance with the Applicable
Procedures as in effect from time to time.

     The person in whose name the Common Stock certificate is registered shall
be deemed to be a stockholder of record on the Conversion Date; PROVIDED,
HOWEVER, that no surrender of a Security on any date when the stock transfer
books of the Company shall be closed shall be effective to constitute the person
or persons entitled to receive the shares of Common Stock upon such conversion
as the record holder or holders of such shares of Common Stock on such date, but
such surrender shall be effective to constitute the person or persons entitled
to receive such shares of Common Stock as the record holder or holders thereof
for all purposes at the close of business on the next succeeding day on which
such stock transfer books are open; PROVIDED, FURTHER, that such conversion
shall be at the Conversion Price in effect on the Conversion Date as if the
stock transfer books of the Company had not been closed. Upon conversion of a
Security, such person shall no longer be a Holder of such Security. No payment
or adjustment will be made for dividends or distributions on shares of Common
Stock issued upon conversion of a Security.

     Securities so surrendered for conversion (in whole or in part) during the
period from the close of business on any regular record date to the opening of
business on the next succeeding interest payment date (excluding Securities or
portions thereof called for redemption or presented for purchase upon a Change
in Control on a Redemption Date or Change in Control Purchase Date, as the case
may be, during the period beginning at the close of business on a regular record
date and ending at the opening of business on the first Business Day after the
next succeeding interest payment date, or if such interest payment date is not a
Business Day, the second such Business Day) shall also be accompanied by payment
in funds acceptable to the Company of an amount equal to the interest payable on
such interest payment date on the principal amount of such Security then being
converted, and such interest shall be payable to such registered Holder
notwithstanding the conversion of such Security, subject to the provisions of
this Indenture relating to the payment of defaulted interest by the Company.
Except as otherwise provided in this Section 4.2, no payment or adjustment will
be made for accrued interest on a converted Security. If the Company defaults in
the payment of interest payable on such interest payment date, the Company shall
promptly repay such funds to such Holder.

     Nothing in this Section shall affect the right of a Holder in whose name
any Security is registered at the close of business on a record date to receive
the interest payable on such Security on the related interest payment date in
accordance with the terms of this Indenture and the Securities. If a Holder
converts more than one Security at the same time, the number of shares of Common
Stock issuable upon the conversion shall be based on the aggregate principal
amount of Securities converted.

     Upon surrender of a Security that is converted in part, the Company shall
execute, and the Trustee shall authenticate and deliver to the Holder, a new
Security equal in principal amount to the unconverted portion of the Security
surrendered.

     SECTION 4.3. FRACTIONAL SHARES.

     The Company will not issue fractional shares of Common Stock upon
conversion of Securities. In lieu thereof, the Company will pay an amount in
cash for the current market value of the fractional shares. The current market
value of a fractional share shall be determined, (calculated to the nearest
1/1000th of a share) by multiplying the Closing Price (determined as set forth
in Section 4.6(d)) of the Common Stock on

                                       23
<Page>

the Trading Day immediately prior to the Conversion Date by such fractional
share and rounding the product to the nearest whole cent.

     SECTION 4.4. TAXES ON CONVERSION.

     If a Holder converts a Security, the Company shall pay any documentary,
stamp or similar issue or transfer tax due on the issue of shares of Common
Stock upon such conversion. However, the Holder shall pay any such tax which is
due because the Holder requests the shares to be issued in a name other than the
Holder's name. The Conversion Agent may refuse to deliver the certificate
representing the Common Stock being issued in a name other than the Holder's
name until the Conversion Agent receives a sum sufficient to pay any tax which
will be due because the shares are to be issued in a name other than the
Holder's name. Nothing herein shall preclude any tax withholding required by law
or regulation.

     SECTION 4.5. COMPANY TO PROVIDE STOCK.

     The Company shall, prior to issuance of any Securities hereunder, and from
time to time as may be necessary, reserve, out of its authorized but unissued
Common Stock, a sufficient number of shares of Common Stock to permit the
conversion of all outstanding Securities into shares of Common Stock.

     All shares of Common Stock delivered upon conversion of the Securities
shall be newly issued shares, shall be duly authorized, validly issued, fully
paid and nonassessable and shall be free from preemptive rights and free of any
lien or adverse claim.

     The Company will endeavor promptly to comply with all federal and state
securities laws regulating the offer and delivery of shares of Common Stock upon
conversion of Securities, if any, and will list or cause to have quoted such
shares of Common Stock on each national securities exchange or on the Nasdaq
National Market or other over-the-counter market or such other market on which
the Common Stock is then listed or quoted; PROVIDED, HOWEVER, that if rules of
such automated quotation system or exchange permit the Company to defer the
listing of such Common Stock until the first conversion of the Notes into Common
Stock in accordance with the provisions of this Indenture, the Company covenants
to list such Common Stock issuable upon conversion of the Notes in accordance
with the requirements of such automated quotation system or exchange at such
time. Any Common Stock issued upon conversion of a Security hereunder which at
the time of conversion was a Transfer Restricted Security will also be a
Transfer Restricted Security.

     SECTION 4.6. ADJUSTMENT OF CONVERSION PRICE.

     The conversion price as stated in paragraph 9 of the Securities (the
"Conversion Price") shall be adjusted from time to time by the Company as
follows:

     (a) In case the Company shall (i) pay a dividend on its Common Stock in
shares of Common Stock, (ii) make a distribution on its Common Stock in shares
of Common Stock, (iii) subdivide its outstanding Common Stock into a greater
number of shares, or (iv) combine its outstanding Common Stock into a smaller
number of shares, the Conversion Price in effect immediately prior thereto shall
be adjusted so that the Holder of any Security thereafter surrendered for
conversion shall be entitled to receive that number of shares of Common Stock
which it would have owned had such Security been converted immediately prior to
the happening of such event. An adjustment made pursuant to this subsection (a)
shall become effective immediately after the record date in the case of a
dividend or distribution and shall become effective immediately after the
effective date in the case of subdivision or combination.

                                       24
<Page>

     (b) In case the Company shall issue rights or warrants to all or
substantially all holders of its Common Stock entitling them (for a period
commencing no earlier than the record date described below and expiring not more
than 60 days after such record date) to subscribe for or purchase shares of
Common Stock (or securities convertible into Common Stock) at a price per share
(or having a conversion price per share) less than the Current Market Price per
share of Common Stock (as determined in accordance with subsection (d) of this
Section 4.6) on the record date for the determination of stockholders entitled
to receive such rights or warrants, the Conversion Price in effect immediately
prior thereto shall be adjusted so that the same shall equal the price
determined by multiplying the Conversion Price in effect immediately prior to
such record date by a fraction of which the numerator shall be the number of
shares of Common Stock outstanding on such record date plus the number of shares
which the aggregate offering price of the total number of shares of Common Stock
so offered (or the aggregate conversion price of the convertible securities so
offered, which shall be determined by multiplying the number of shares of Common
Stock issuable upon conversion of such convertible securities by the conversion
price per share of Common Stock pursuant to the terms of such convertible
securities) would purchase at the Current Market Price per share (as defined in
subsection (d) of this Section 4.6) of Common Stock on such record date, and of
which the denominator shall be the number of shares of Common Stock outstanding
on such record date plus the number of additional shares of Common Stock offered
(or into which the convertible securities so offered are convertible). Such
adjustment shall be made successively whenever any such rights or warrants are
issued, and shall become effective immediately after such record date. If at the
end of the period during which such rights or warrants are exercisable not all
rights or warrants shall have been exercised, the adjusted Conversion Price
shall be immediately readjusted to what it would have been based upon the number
of additional shares of Common Stock actually issued (or the number of shares of
Common Stock issuable upon conversion of convertible securities actually
issued).

     (c) In case the Company shall distribute to all or substantially all
holders of its Common Stock any shares of capital stock of the Company (other
than Common Stock), evidences of indebtedness or other non-cash assets
(including securities of any person other than the Company but excluding (1)
dividends or distributions paid exclusively in cash or (2) dividends or
distributions referred to in subsection (a) of this Section 4.6), or shall
distribute to all or substantially all holders of its Common Stock rights or
warrants to subscribe for or purchase any of its securities (excluding those
rights and warrants referred to in subsection (b) of this Section 4.6 and also
excluding the distribution of rights to all holders of Common Stock pursuant to
the adoption of a stockholders rights plan or the detachment of such rights
under the terms of such stockholder rights plan), then in each such case the
Conversion Price shall be adjusted so that the same shall equal the price
determined by multiplying the current Conversion Price by a fraction of which
the numerator shall be the Current Market Price per share (as defined in
subsection (d) of this Section 4.6) of the Common Stock on the record date
mentioned below less the fair market value on such record date (as determined by
the Board of Directors, whose determination shall be conclusive evidence of such
fair market value and which shall be evidenced by an Officers' Certificate
delivered to the Trustee) of the portion of the capital stock, evidences of
indebtedness or other non-cash assets so distributed or of such rights or
warrants applicable to one share of Common Stock (determined on the basis of the
number of shares of Common Stock outstanding on the record date), and of which
the denominator shall be the Current Market Price per share (as defined in
subsection (d) of this Section 4.6) of the Common Stock on such record date.
Such adjustment shall be made successively whenever any such distribution is
made and shall become effective immediately after the record date for the
determination of shareholders entitled to receive such distribution.

     In the event the then fair market value (as so determined) of the portion
of the capital stock, evidences of indebtedness or other non-cash assets so
distributed or of such rights or warrants applicable to one share of Common
Stock is equal to or greater than the Current Market Price per share of the
Common Stock on such record date, in lieu of the foregoing adjustment, adequate
provision shall be made so that each holder of a

                                       25
<Page>

Security shall have the right to receive upon conversion the amount of capital
stock, evidences of indebtedness or other non-cash assets so distributed or of
such rights or warrants such holder would have received had such holder
converted each Security on such record date. In the event that such dividend or
distribution is not so paid or made, the Conversion Price shall again be
adjusted to be the Conversion Price which would then be in effect if such
dividend or distribution had not been declared. If the Board of Directors
determines the fair market value of any distribution for purposes of this
Section 4.6(c) by reference to the actual or when issued trading market for any
securities, it must in doing so consider the prices in such market over the same
period used in computing the Current Market Price of the Common Stock.

     In the event that the Company implements a preferred shares rights plan
("Rights Plan"), upon conversion of the Securities into Common Stock, to the
extent that the Rights Plan has been implemented and is still in effect upon
such conversion, the holders of Securities will receive, in addition to the
Common Stock, the rights described therein (whether or not the rights have
separated from the Common Stock at the time of conversion), subject to the
limitations set forth in the Rights Plan. Any distribution of rights or warrants
pursuant to a Rights Plan complying with the requirements set forth in the
immediately preceding sentence of this paragraph shall not constitute a
distribution of rights or warrants pursuant to this Section 4.6(c).

     Rights or warrants distributed by the Company to all holders of Common
Stock entitling the holders thereof to subscribe for or purchase shares of the
Company's Capital Stock (either initially or under certain circumstances), which
rights or warrants, until the occurrence of a specified event or events
("Trigger Event"): (i) are deemed to be transferred with such shares of Common
Stock; (ii) are not exercisable; and (iii) are also issued in respect of future
issuances of Common Stock, shall be deemed not to have been distributed for
purposes of this Section 4.6 (and no adjustment to the Conversion Price under
this Section 4.6 will be required) until the occurrence of the earliest Trigger
Event, whereupon such rights and warrants shall be deemed to have been
distributed and an appropriate adjustment (if any is required) to the Conversion
Price shall be made under this Section 4.6(c). If any such right or warrant,
including any such existing rights or warrants distributed prior to the date of
this Indenture, are subject to events, upon the occurrence of which such rights
or warrants become exercisable to purchase different securities, evidences of
indebtedness or other assets, then the date of the occurrence of any and each
such event shall be deemed to be the date of distribution and record date with
respect to new rights or warrants with such rights (and a termination or
expiration of the existing rights or warrants without exercise by any of the
holders thereof). In addition, in the event of any distribution (or deemed
distribution) of rights or warrants, or any Trigger Event or other event (of the
type described in the preceding sentence) with respect thereto that was counted
for purposes of calculating a distribution amount for which an adjustment to the
Conversion Price under this Section 4.6 was made, (1) in the case of any such
rights or warrants which shall all have been redeemed or repurchased without
exercise by any holders thereof, the Conversion Price shall be readjusted upon
such final redemption or repurchase to give effect to such distribution or
Trigger Event, as the case may be, as though it were a cash distribution, equal
to the per share redemption or repurchase price received by a holder or holders
of Common Stock with respect to such rights or warrants (assuming such holder
had retained such rights or warrants), made to all holders of Common Stock as of
the date of such redemption or repurchase, and (2) in the case of such rights or
warrants which shall have expired or been terminated without exercise by any
holders thereof, the Conversion Price shall be readjusted as if such rights and
warrants had not been issued.

          (1) In case the Company shall, by dividend or otherwise, at any time
distribute (a "Triggering Distribution") to all or substantially all holders of
its Common Stock cash in an aggregate amount that, together with the aggregate
amount of (A) any cash and the fair market value (as determined by the Board of
Directors, whose determination shall be conclusive evidence thereof and which
shall be evidenced by an Officers' Certificate delivered to the Trustee) of any
other consideration payable in respect of any

                                       26
<Page>

tender offer by the Company or a Subsidiary of the Company for Common Stock
consummated within the 12 months preceding the date of payment of the Triggering
Distribution and in respect of which no Conversion Price adjustment pursuant to
this Section 4.6 has been made and (B) all other cash distributions to all or
substantially all holders of its Common Stock made within the 12 months
preceding the date of payment of the Triggering Distribution and in respect of
which no Conversion Price adjustment pursuant to this Section 4.6 has been made,
exceeds an amount equal to 10.0% of the product of the Current Market Price per
share of Common Stock (as determined in accordance with subsection (d) of this
Section 4.6) on the Business Day (the "Determination Date") immediately
preceding the day on which such Triggering Distribution is declared by the
Company multiplied by the number of shares of Common Stock outstanding on the
Determination Date (excluding shares held in the treasury of the Company), the
Conversion Price shall be reduced so that the same shall equal the price
determined by multiplying such Conversion Price in effect immediately prior to
the Determination Date by a fraction of which the numerator shall be the Current
Market Price per share of the Common Stock (as determined in accordance with
subsection (d) of this Section 4.6) on the Determination Date less the sum of
the aggregate amount of cash and the aggregate fair market value (determined as
aforesaid in this Section 4.6(c)(1)) of any such other consideration so
distributed, paid or payable within such 12 months (including, without
limitation, the Triggering Distribution) applicable to one share of Common Stock
(determined on the basis of the number of shares of Common Stock outstanding on
the Determination Date) and the denominator shall be such Current Market Price
per share of the Common Stock (as determined in accordance with subsection (d)
of this Section 4.6) on the Determination Date, such reduction to become
effective immediately prior to the opening of business on the day following the
date on which the Triggering Distribution is paid.

          (2) In case any tender offer made by the Company or any of its
Subsidiaries for Common Stock shall expire and such tender offer (as amended
upon the expiration thereof) shall involve the payment of aggregate
consideration in an amount (determined as the sum of the aggregate amount of
cash consideration and the aggregate fair market value (as determined by the
Board of Directors, whose determination shall be conclusive evidence thereof and
which shall be evidenced by an Officers' Certificate delivered to the Trustee
thereof) of any other consideration) that, together with the aggregate amount of
(A) any cash and the fair market value (as determined by the Board of Directors,
whose determination shall be conclusive evidence thereof and which shall be
evidenced by an Officers' Certificate delivered to the Trustee) of any other
consideration payable in respect of any other tender offers by the Company or
any Subsidiary of the Company for Common Stock consummated within the 12 months
preceding the date of the Expiration Date (as defined below) and in respect of
which no Conversion Price adjustment pursuant to this Section 4.6 has been made
and (B) all cash distributions to all or substantially all holders of its Common
Stock made within the 12 months preceding the Expiration Date and in respect of
which no Conversion Price adjustment pursuant to this Section 4.6 has been made,
exceeds an amount equal to 10.0% of the product of the Current Market Price per
share of Common Stock (as determined in accordance with subsection (d) of this
Section 4.6) as of the last date (the "Expiration Date") tenders could have been
made pursuant to such tender offer (as it may be amended) (the last time at
which such tenders could have been made on the Expiration Date is hereinafter
sometimes called the "Expiration Time") multiplied by the number of shares of
Common Stock outstanding (including tendered shares but excluding any shares
held in the treasury of the Company) at the Expiration Time, then, immediately
prior to the opening of business on the day after the Expiration Date, the
Conversion Price shall be reduced so that the same shall equal the price
determined by multiplying the Conversion Price in effect immediately prior to
the close of business on the Expiration Date by a fraction of which the
numerator shall be the product of the number of shares of Common Stock
outstanding (including tendered shares but excluding any shares held in the
treasury of the Company) at the Expiration Time multiplied by the Current Market
Price per share of the Common Stock (as determined in accordance with subsection
(d) of this Section 4.6) on the Trading Day next succeeding the Expiration Date
and the

                                       27
<Page>

denominator shall be the sum of (x) the aggregate consideration (determined as
aforesaid) payable to stockholders based on the acceptance (up to any maximum
specified in the terms of the tender offer) of all shares validly tendered and
not withdrawn as of the Expiration Time (the shares deemed so accepted, up to
any such maximum, being referred to as the "Purchased Shares") and (y) the
product of the number of shares of Common Stock outstanding (less any Purchased
Shares and excluding any shares held in the treasury of the Company) at the
Expiration Time and the Current Market Price per share of Common Stock (as
determined in accordance with subsection (d) of this Section 4.6) on the Trading
Day next succeeding the Expiration Date, such reduction to become effective
immediately prior to the opening of business on the day following the Expiration
Date. In the event that the Company is obligated to purchase shares pursuant to
any such tender offer, but the Company is permanently prevented by applicable
law from effecting any or all such purchases or any or all such purchases are
rescinded, the Conversion Price shall again be adjusted to be the Conversion
Price which would have been in effect based upon the number of shares actually
purchased. If the application of this Section 4.6(c)(2) to any tender offer
would result in an increase in the Conversion Price, no adjustment shall be made
for such tender offer under this Section 4.6(c)(2).

          (3) For purposes of this Section 4.6(c), the term "tender offer" shall
mean and include both tender offers and exchange offers, all references to
"purchases" of shares in tender offers (and all similar references) shall mean
and include both the purchase of shares in tender offers and the acquisition of
shares pursuant to exchange offers, and all references to "tendered shares" (and
all similar references) shall mean and include shares tendered in both tender
offers and exchange offers.

     (d) For the purpose of any computation under subsections (b) and (c) of
this Section 4.6, the current market price (the "Current Market Price") per
share of Common Stock on any date shall be deemed to be the average of the daily
closing prices for the 30 consecutive Trading Days commencing 45 Trading Days
before (i) the Determination Date or the Expiration Date, as the case may be,
with respect to distributions or tender offers under subsection (c) of this
Section 4.6 or (ii) the record date with respect to distributions, issuances or
other events requiring such computation under subsection (b) or (c) of this
Section 4.6. The closing price (the "Closing Price") for each day shall be the
last reported sales price or, in case no such reported sale takes place on such
date, the average of the reported closing bid and asked prices in either case on
the Nasdaq National Market (the "NNM") or, if the Common Stock is not listed or
admitted to trading on the NNM, on the principal national securities exchange on
which the Common Stock is listed or admitted to trading or, if not listed or
admitted to trading on the NNM or any national securities exchange, the last
reported sales price of the Common Stock as quoted on NASDAQ or, in case no
reported sales takes place, the average of the closing bid and asked prices as
quoted on NASDAQ or any comparable system or, if the Common Stock is not quoted
on NASDAQ or any comparable system, the closing sales price or, in case no
reported sale takes place, the average of the closing bid and asked prices, as
furnished by any two members of the National Association of Securities Dealers,
Inc. selected from time to time by the Company for that purpose. If no such
prices are available, the Current Market Price per share shall be the fair value
of a share of Common Stock as determined by the Board of Directors (which shall
be evidenced by an Officers' Certificate delivered to the Trustee).

     (e) In any case in which this Section 4.6 shall require that an adjustment
be made following a record date or a Determination Date or Expiration Date, as
the case may be, established for purposes of this Section 4.6, the Company may
elect to defer (but only until five Business Days following the filing by the
Company with the Trustee of the certificate described in Section 4.9) issuing to
the Holder of any Security converted after such record date or Determination
Date or Expiration Date the shares of Common Stock and other capital stock of
the Company issuable upon such conversion over and above the shares of Common
Stock and other capital stock of the Company issuable upon such conversion only
on the basis of the

                                       28
<Page>

Conversion Price prior to adjustment; and, in lieu of the shares the issuance of
which is so deferred, the Company shall issue or cause its transfer agents to
issue due bills or other appropriate evidence prepared by the Company of the
right to receive such shares. If any distribution in respect of which an
adjustment to the Conversion Price is required to be made as of the record date
or Determination Date or Expiration Date therefor is not thereafter made or paid
by the Company for any reason, the Conversion Price shall be readjusted to the
Conversion Price which would then be in effect if such record date had not been
fixed or such effective date or Determination Date or Expiration Date had not
occurred.

     SECTION 4.7. NO ADJUSTMENT.

     No adjustment in the Conversion Price shall be required unless the
adjustment would require an increase or decrease of at least 1% in the
Conversion Price as last adjusted; PROVIDED, HOWEVER, that any adjustments which
by reason of this Section 4.7 are not required to be made shall be carried
forward and taken into account in any subsequent adjustment. All calculations
under this Article 4 shall be made to the nearest cent or to the nearest
one-hundredth of a share, as the case may be.

     No adjustment need be made for issuances of Common Stock pursuant to a
Company plan for reinvestment of dividends or interest or for a change in the
par value or a change to no par value of the Common Stock.

     To the extent that the Securities become convertible into the right to
receive cash, no adjustment need be made thereafter as to the cash. Interest
will not accrue on the cash.

     SECTION 4.8. ADJUSTMENT FOR TAX PURPOSES.

     The Company shall be entitled to make such reductions in the Conversion
Price, in addition to those required by Section 4.6, as it in its discretion
shall determine to be advisable in order that any stock dividends, subdivisions
of shares, distributions of rights to purchase stock or securities or
distributions of securities convertible into or exchangeable for stock hereafter
made by the Company to its stockholders shall not be taxable.

     SECTION 4.9. NOTICE OF ADJUSTMENT.

     Whenever the Conversion Price or conversion privilege is adjusted, the
Company shall promptly mail to Securityholders a notice of the adjustment and
file with the Trustee an Officers' Certificate briefly stating the facts
requiring the adjustment and the manner of computing it. Unless and until the
Trustee shall receive an Officers' Certificate setting forth an adjustment of
the Conversion Price, the Trustee may assume without inquiry that the Conversion
Price has not been adjusted and that the last Conversion Price of which it has
knowledge remains in effect.

     SECTION 4.10. NOTICE OF CERTAIN TRANSACTIONS.

     In the event that:

          (1) the Company takes any action which would require an adjustment in
the Conversion Price;

          (2) the Company consolidates or merges with, or transfers all or
substantially all of its property and assets to, another corporation and
shareholders of the Company must approve the transaction; or

                                       29
<Page>

          (3) there is a dissolution or liquidation of the Company,

the Company shall mail to Holders and file with the Trustee a notice stating the
proposed record or effective date, as the case may be. The Company shall mail
the notice at least ten days before such date. Failure to mail such notice or
any defect therein shall not affect the validity of any transaction referred to
in clause (1), (2) or (3) of this Section 4.10.

     SECTION 4.11. EFFECT OF RECLASSIFICATION, CONSOLIDATION, MERGER OR SALE ON
CONVERSION PRIVILEGE.

     If any of the following shall occur, namely: (a) any reclassification or
change of shares of Common Stock issuable upon conversion of the Securities
(other than a change in par value, or from par value to no par value, or from no
par value to par value, or as a result of a subdivision or combination, or any
other change for which an adjustment is provided in Section 4.6); (b) any
consolidation or merger or combination to which the Company is a party other
than a merger in which the Company is the continuing corporation and which does
not result in any reclassification of, or change (other than in par value, or
from par value to no par value, or from no par value to par value, or as a
result of a subdivision or combination) in, outstanding shares of Common Stock;
or (c) any sale or conveyance as an entirety or substantially as an entirety of
the property and assets of the Company, directly or indirectly, to any person,
then the Company, or such successor, purchasing or transferee corporation, as
the case may be, shall, as a condition precedent to such reclassification,
change, combination, consolidation, merger, sale or conveyance, execute and
deliver to the Trustee a supplemental indenture providing that the Holder of
each Security then outstanding shall have the right to convert such Security
into the kind and amount of shares of stock and other securities and property
(including cash) receivable upon such reclassification, change, combination,
consolidation, merger, sale or conveyance by a holder of the number of shares of
Common Stock deliverable upon conversion of such Security immediately prior to
such reclassification, change, combination, consolidation, merger, sale or
conveyance. Such supplemental indenture shall provide for adjustments of the
Conversion Price which shall be as nearly equivalent as may be practicable to
the adjustments of the Conversion Price provided for in this Article 4. If, in
the case of any such consolidation, merger, combination, sale or conveyance, the
stock or other securities and property (including cash) receivable thereupon by
a holder of Common Stock include shares of stock or other securities and
property of a person other than the successor, purchasing or transferee
corporation, as the case may be, in such consolidation, merger, combination,
sale or conveyance, then such supplemental indenture shall also be executed by
such other person and shall contain such additional provisions to protect the
interests of the Holders of the Securities as the Board of Directors shall
reasonably consider necessary by reason of the foregoing. The provisions of this
Section 4.11 shall similarly apply to successive reclassifications, changes,
combinations, consolidations, mergers, sales or conveyances.

     In the event the Company shall execute a supplemental indenture pursuant to
this Section 4.11, the Company shall promptly file with the Trustee (x) an
Officers' Certificate briefly stating the reasons therefor, the kind or amount
of shares of stock or other securities or property (including cash) receivable
by Holders of the Securities upon the conversion of their Securities after any
such reclassification, change, combination, consolidation, merger, sale or
conveyance, any adjustment to be made with respect thereto and that all
conditions precedent have been complied with and (y) an Opinion of Counsel that
all conditions precedent have been complied with, and shall promptly mail notice
thereof to all Holders.

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     SECTION 4.12. TRUSTEE'S DISCLAIMER.

     The Trustee shall have no duty to determine when an adjustment under this
Article 4 should be made, how it should be made or what such adjustment should
be, but may accept as conclusive evidence of that fact or the correctness of any
such adjustment, and shall be protected in relying upon, an Officers'
Certificate including the Officers' Certificate with respect thereto which the
Company is obligated to file with the Trustee pursuant to Section 4.9. The
Trustee makes no representation as to the validity or value of any securities or
assets issued upon conversion of Securities, and the Trustee shall not be
responsible for the Company's failure to comply with any provisions of this
Article 4.

     The Trustee shall not be under any responsibility to determine the
correctness of any provisions contained in any supplemental indenture executed
pursuant to Section 4.11, but may accept as conclusive evidence of the
correctness thereof, and shall be fully protected in relying upon, the Officers'
Certificate with respect thereto which the Company is obligated to file with the
Trustee pursuant to Section 4.11.

     SECTION 4.13. VOLUNTARY REDUCTION.

     The Company from time to time may reduce the Conversion Price by any amount
for any period of time if the period is at least 20 days and if the reduction is
irrevocable during the period if our Board of Directors determines that such
reduction would be in the best interest of the Company or to avoid or diminish
income tax to holders of shares of our Common Stock in connection with a
dividend or distribution of stock or similar event, and the Company provides 15
days prior notice of any reduction in the Conversion Price; PROVIDED, HOWEVER,
that in no event may the Company reduce the Conversion Price to be less than the
par value of a share of Common Stock.

                                    ARTICLE 5
                                 SUBORDINATION

     SECTION 5.1. AGREEMENT OF SUBORDINATION.

     The Company covenants and agrees, and each Holder of Securities issued
hereunder by its acceptance thereof likewise covenants and agrees, that all
Securities shall be issued subject to the provisions of this Article 5; and each
Person holding any Security, whether upon original issue or upon transfer,
assignment or exchange thereof, accepts and agrees to be bound by such
provisions.

     The payment of the principal of, premium, if any, and interest (including
Special Interest, if any) on all Securities (including, but not limited to, the
Redemption Price with respect to the Securities called for redemption or the
Change in Control Purchase Price with respect to the Securities subject to
purchase in accordance with Article 3 as provided in this Indenture) issued
hereunder shall, to the extent and in the manner hereinafter set forth, be
subordinated and subject in right of payment to the prior payment in full in
cash or payment satisfactory to the holders of Senior Indebtedness of all Senior
Indebtedness, whether outstanding at the date of this Indenture or thereafter
incurred. The Securities are not senior in right of payment to the Company's 5
1/2% Convertible Subordinated Notes due 2007.

     No provision of this Article 5 shall prevent the occurrence of any default
or Event of Default hereunder.

                                       31
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     SECTION 5.2. PAYMENTS TO HOLDERS.

     No payment shall be made with respect to the principal of, or premium, if
any, or interest (including Special Interest, if any) on the Securities
(including, but not limited to, the Redemption Price with respect to the
Securities to be called for redemption or the Change in Control Purchase Price
with respect to the Securities subject to purchase in accordance with Article 3
as provided in this Indenture), except payments and distributions made by the
Trustee as permitted by the first or second paragraph of Section 5.5, if:

     (i)  a default in the payment of principal, premium, interest, rent or
other obligations due on any Designated Senior Indebtedness occurs and is
continuing (or, in the case of Designated Senior Indebtedness for which there is
a period of grace, in the event of such a default that continues beyond the
period of grace, if any, specified in the instrument or lease evidencing such
Designated Senior Indebtedness), unless and until such default shall have been
cured or waived or shall have ceased to exist; or

     (ii) a default, other than a payment default, on a Designated Senior
Indebtedness occurs and is continuing that then permits holders of such
Designated Senior Indebtedness to accelerate its maturity and the Trustee
receives a notice of the default (a "Payment Blockage Notice") from a
Representative or holder of Designated Senior Indebtedness or the Company.

     Subject to the provisions of Section 5.5, if the Trustee receives any
Payment Blockage Notice pursuant to clause (ii) above, no subsequent Payment
Blockage Notice shall be effective for purposes of this Section unless and until
(a) at least 365 days shall have elapsed since the initial effectiveness of the
immediately prior Payment Blockage Notice; and (b) all scheduled payments on the
Securities that have come due have been paid in full in cash. No nonpayment
default that existed or was continuing on the date of delivery of any Payment
Blockage Notice to the Trustee (unless such default was waived, cured or
otherwise ceased to exist and thereafter subsequently reoccurred) shall be, or
be made, the basis for a subsequent Payment Blockage Notice.

     The Company may and shall resume payments on and distributions in respect
of the Securities upon the earlier of:

     (a) in the case of a default referred to in clause (i) above, the date upon
which the default is cured or waived or ceases to exist, or

     (b) in the case of a default referred to in clause (ii) above, the earlier
of the date on which such default is cured or waived or ceases to exist or 179
days pass after the date on which the applicable Payment Blockage Notice is
received, if the maturity of such Designated Senior Indebtedness has not been
accelerated, unless this Article 5 otherwise prohibits the payment or
distribution at the time of such payment or distribution.

     Upon any payment by the Company, or distribution of assets of the Company
of any kind or character, whether in cash, property or securities, to creditors
upon any dissolution or winding-up or liquidation or reorganization of the
Company (whether voluntary or involuntary) or in bankruptcy, insolvency,
receivership or similar proceedings, all amounts due or to become due upon all
Senior Indebtedness shall first be paid in full in cash, or other payments
satisfactory to the holders of Senior Indebtedness before any payment is made on
account of the principal of, premium, if any, or interest (including Special
Interest, if any) on the Securities (except payments made pursuant to Article 10
from monies deposited with the Trustee pursuant thereto prior to commencement of
proceedings for such

                                       32
<Page>

dissolution, winding-up, liquidation or reorganization); and upon any such
dissolution or winding-up or liquidation or reorganization of the Company or
bankruptcy, insolvency, receivership or other proceeding, any payment by the
Company, or distribution of assets of the Company of any kind or character,
whether in cash, property or securities, to which the Holders of the Securities
or the Trustee would be entitled, except for the provision of this Article 5,
shall (except as aforesaid) be paid by the Company or by any receiver, trustee
in bankruptcy, liquidating trustee, agent or other Person making such payment or
distribution, or by the Holders of the Securities or by the Trustee under this
Indenture if received by them or it, directly to the holders of Senior
Indebtedness (pro rata to such holders on the basis of the respective amounts of
Senior Indebtedness held by such holders, or as otherwise required by law or a
court order) or their representative or representatives, or to the trustee or
trustees under any indenture pursuant to which any instruments evidencing any
Senior Indebtedness may have been issued, as their respective interests may
appear, to the extent necessary to pay all Senior Indebtedness in full in cash,
or other payment satisfactory to the holders of Senior Indebtedness, after
giving effect to any concurrent payment or distribution to or for the holders of
Senior Indebtedness, before any payment or distribution is made to the Holders
of the Securities or to the Trustee.

     For purposes of this Article 5, the words, "cash, property or securities"
shall not be deemed to include shares of stock of the Company as reorganized or
readjusted, or securities of the Company or any other corporation provided for
by a plan of reorganization or readjustment, the payment of which is
subordinated at least to the extent provided in this Article 5 with respect to
the Securities to the payment of all Senior Indebtedness which may at the time
be outstanding; PROVIDED THAT (i) the Senior Indebtedness is assumed by the new
corporation, if any, resulting from any reorganization or readjustment, and (ii)
the rights of the holders of Senior Indebtedness (other than leases which are
not assumed by the Company or the new corporation, as the case may be) are not,
without the consent of such holders, altered by such reorganization or
readjustment. The consolidation of the Company with, or the merger of the
Company into, another corporation or the liquidation or dissolution of the
Company following the conveyance, transfer or lease of its property as an
entirety, or substantially as an entirety, to another corporation upon the terms
and conditions provided for in Article 7 shall not be deemed a dissolution,
winding-up, liquidation or reorganization for the purposes of this Section 5.2
if such other corporation shall, as a part of such consolidation, merger,
conveyance, transfer or lease, comply with the conditions stated in Article 7.

     In the event of the acceleration of the Securities because of an Event of
Default, no payment or distribution shall be made to the Trustee or any Holder
of Securities in respect of the principal of, premium, if any, or interest
(including Special Interest, if any) on the Securities by the Company
(including, but not limited to, the Redemption Price with respect to the
Securities called for redemption or the Change in Control Purchase Price with
respect to the Securities subject to purchase in accordance with Article 3 as
provided in this Indenture), except payments and distributions made by the
Trustee as permitted by Section 5.5, until all Senior Indebtedness has been paid
in full in cash or other payment satisfactory to the holders of Senior
Indebtedness or such acceleration is rescinded in accordance with the terms of
this Indenture. If payment of the Securities is accelerated because of an Event
of Default, the Company shall promptly notify holders of Senior Indebtedness of
such acceleration.

     In the event that, notwithstanding the foregoing provisions, any payment or
distribution of assets of the Company of any kind or character, whether in cash,
property or securities (including, without limitation, by way of setoff or
otherwise), prohibited by the foregoing, shall be received by the Trustee or the
Holders of the Securities before all Senior Indebtedness is paid in full, in
cash or other payment satisfactory to the holders of Senior Indebtedness, or
provision is made for such payment thereof in accordance with its terms in cash
or other payment satisfactory to the holders of Senior Indebtedness, such
payment or distribution shall be held in trust for the benefit of and shall be
paid over or delivered to the holders of Senior Indebtedness or their

                                       33
<Page>

representative or representatives, or to the trustee or trustees under any
indenture pursuant to which any instruments evidencing any Senior Indebtedness
may have been issued, as their respective interests may appear, as calculated by
the Company, for application to the payment of all Senior Indebtedness remaining
unpaid to the extent necessary to pay all Senior Indebtedness in full, in cash
or other payment satisfactory to the holders of Senior Indebtedness, after
giving effect to any concurrent payment or distribution to or for the holders of
such Senior Indebtedness.

     Nothing in this Section 5.2 shall apply to claims of, or payments to, the
Trustee under or pursuant to Section 9.7. This Section 5.2 shall be subject to
the further provisions of Section 5.5.

     SECTION 5.3. SUBROGATION OF SECURITIES.

     Subject to the payment in full, in cash or other payment satisfactory to
the holders of Senior Indebtedness, of all Senior Indebtedness, the rights of
the Holders of the Securities shall be subrogated to the extent of the payments
or distributions made to the holders of such Senior Indebtedness pursuant to the
provisions of this Article 5 (equally and ratably with the holders of all
indebtedness of the Company which by its express terms is subordinated to other
indebtedness of the Company to substantially the same extent as the Securities
are subordinated and is entitled to like rights of subrogation) to the rights of
the holders of Senior Indebtedness to receive payments or distributions of cash,
property or securities of the Company applicable to the Senior Indebtedness
until the principal, premium, if any, and interest (including Special Interest,
if any) on the Securities shall be paid in full in cash or other payment
satisfactory to the holders of Senior Indebtedness; and, for the purposes of
such subrogation, no payments or distributions to the holders of the Senior
Indebtedness of any cash, property or securities to which the Holders of the
Securities or the Trustee would be entitled except for the provisions of this
Article 5, and no payment over pursuant to the provisions of this Article 5, to
or for the benefit of the holders of Senior Indebtedness by Holders of the
Securities or the Trustee, shall, as between the Company, its creditors other
than holders of Senior Indebtedness, and the Holders of the Securities, be
deemed to be a payment by the Company to or on account of the Senior
Indebtedness; and no payments or distributions of cash, property or securities
to or for the benefit of the Holders of the Securities pursuant to the
subrogation provisions of this Article 5, which would otherwise have been paid
to the holders of Senior Indebtedness shall be deemed to be a payment by the
Company to or for the account of the Securities. It is understood that the
provisions of this Article 5 are and are intended solely for the purposes of
defining the relative rights of the Holders of the Securities, on the one hand,
and the holders of the Senior Indebtedness, on the other hand.

     Nothing contained in this Article 5 or elsewhere in this Indenture or in
the Securities is intended to or shall impair, as among the Company, its
creditors other than the holders of Senior Indebtedness, and the Holders of the
Securities, the obligation of the Company, which is absolute and unconditional,
to pay to the Holders of the Securities the principal of (and premium, if any)
and interest on the Securities as and when the same shall become due and payable
in accordance with their terms, or is intended to or shall affect the relative
rights of the Holders of the Securities and creditors of the Company other than
the holders of the Senior Indebtedness, nor shall anything herein or therein
prevent the Trustee or the Holder of any Security from exercising all remedies
otherwise permitted by applicable law upon default under this Indenture, subject
to the rights, if any, under this Article 5 of the holders of Senior
Indebtedness in respect of cash, property or securities of the Company received
upon the exercise of any such remedy.

     Upon any payment or distribution of assets of the Company referred to in
this Article 5, the Trustee, subject to the provisions of Section 9.1, and the
Holders of the Securities shall be entitled to rely upon any order or decree
made by any court of competent jurisdiction in which such bankruptcy,
dissolution, winding-

                                       34
<Page>

up, liquidation or reorganization proceedings are pending, or a certificate of
the receiver, trustee in bankruptcy, liquidating trustee, agent or other person
making such payment or distribution, delivered to the Trustee or to the Holders
of the Securities, for the purpose of ascertaining the persons entitled to
participate in such distribution, the holders of the Senior Indebtedness and
other indebtedness of the Company, the amount thereof or payable thereon and all
other facts pertinent thereto or to this Article 5.

     SECTION 5.4. AUTHORIZATION TO EFFECT SUBORDINATION.

     Each Holder of a Security by the Holder's acceptance thereof authorizes and
directs the Trustee on the Holder's behalf to take such action as may be
necessary or appropriate to effectuate the subordination as provided in this
Article 5 and appoints the Trustee to act as the Holder's attorney-in-fact for
any and all such purposes. If the Trustee does not file a proper proof of claim
or proof of debt in the form required in any proceeding referred to in Section
5.3 hereof at least 30 days before the expiration of the time to file such
claim, the holders of any Senior Indebtedness or their representatives are
hereby authorized to file an appropriate claim for and on behalf of the Holders
of the Securities.

     SECTION 5.5. NOTICE TO TRUSTEE.

     The Company shall give prompt written notice in the form of an Officers'
Certificate to a Trust Officer of the Trustee and to any Paying Agent of any
fact known to the Company which would prohibit the making of any payment of
monies to or by the Trustee or any Paying Agent in respect of the Securities
pursuant to the provisions of this Article 5. Notwithstanding the provisions of
this Article 5 or any other provision of this Indenture, the Trustee shall not
be charged with knowledge of the existence of any facts which would prohibit the
making of any payment of monies to or by the Trustee in respect of the
Securities pursuant to the provisions of this Article 5, unless and until a
Trust Officer of the Trustee shall have received written notice thereof at the
Corporate Trust Office from the Company (in the form of an Officers'
Certificate) or a Representative or a Holder or Holders of Senior Indebtedness
or from any trustee thereof; and before the receipt of any such written notice,
the Trustee, subject to the provisions of Section 9.1, shall be entitled in all
respects to assume that no such facts exist; PROVIDED THAT if on a date not less
than one Business Day prior to the date upon which by the terms hereof any such
monies may become payable for any purpose (including, without limitation, the
payment of the principal of, or premium, if any, or interest on any Security)
the Trustee shall not have received, with respect to such monies, the notice
provided for in this Section 5.5, then, anything herein contained to the
contrary notwithstanding, the Trustee shall have full power and authority to
receive such monies and to apply the same to the purpose for which they were
received, and shall not be affected by any notice to the contrary which may be
received by it on or after such prior date. Notwithstanding anything in this
Article 5 to the contrary, nothing shall prevent any payment by the Trustee to
the Holders of monies deposited with it pursuant to Article 10, and any such
payment shall not be subject to the provisions of Article 5.

     The Trustee, subject to the provisions of Section 9.1, shall be entitled to
rely on the delivery to it of a written notice by a Representative or a person
representing himself to be a holder of Senior Indebtedness (or a trustee on
behalf of such holder) to establish that such notice has been given by a
Representative or a holder of Senior Indebtedness or a trustee on behalf of any
such holder or holders. In the event that the Trustee determines in good faith
that further evidence is required with respect to the right of any person as a
holder of Senior Indebtedness to participate in any payment or distribution
pursuant to this Article 5, the Trustee may request such Person to furnish
evidence to the reasonable satisfaction of the Trustee as to the amount of
Senior Indebtedness held by such Person, the extent to which such Person is
entitled to participate in such payment or distribution and any other facts
pertinent to the rights of such Person under this Article 5, and if

                                       35
<Page>

such evidence is not furnished the Trustee may defer any payment to such Person
pending judicial determination as to the right of such Person to receive such
payment.

     SECTION 5.6. TRUSTEE'S RELATION TO SENIOR INDEBTEDNESS.

     The Trustee in its individual capacity shall be entitled to all the rights
set forth in this Article 5 in respect of any Senior Indebtedness at any time
held by it, to the same extent as any other holder of Senior Indebtedness, and
nothing in Section 9.11 or elsewhere in this Indenture shall deprive the Trustee
of any of its rights as such holder.

     With respect to the holders of Senior Indebtedness, the Trustee undertakes
to perform or to observe only such of its covenants and obligations as are
specifically set forth in this Article 5, and no implied covenants or
obligations with respect to the holders of Senior Indebtedness shall be read
into this Indenture against the Trustee. The Trustee shall not be deemed to owe
any fiduciary duty to the holders of Senior Indebtedness and, subject to the
provisions of Section 9.1, the Trustee shall not be liable to any holder of
Senior Indebtedness if it shall pay over or deliver to Holders of Securities,
the Company or any other person money or assets to which any holder of Senior
Indebtedness shall be entitled by virtue of this Article 5 or otherwise.

     SECTION 5.7. NO IMPAIRMENT OF SUBORDINATION.

     No right of any present or future holder of any Senior Indebtedness to
enforce subordination as herein provided shall at any time in any way be
prejudiced or impaired by any act or failure to act on the part of the Company
or by any act or failure to act, in good faith, by any such holder, or by any
noncompliance by the Company with the terms, provisions and covenants of this
Indenture, regardless of any knowledge thereof which any such holder may have or
otherwise be charged with.

     SECTION 5.8. CERTAIN CONVERSIONS DEEMED PAYMENT.

     For the purposes of this Article 5 only, (1) the issuance and delivery of
junior securities upon conversion of Securities in accordance with Article 4
shall not be deemed to constitute a payment or distribution on account of the
principal of (or premium, if any) or interest on Securities or on account of the
purchase or other acquisition of Securities, and (2) the payment, issuance or
delivery of cash (except in satisfaction of fractional shares pursuant to
Section 4.3), property or securities (other than junior securities) upon
conversion of a Security shall be deemed to constitute payment on account of the
principal of such Security. For the purposes of this Section 5.8, the term
"junior securities" means (a) shares of any stock of any class of the Company,
or (b) securities of the Company which are subordinated in right of payment to
all Senior Indebtedness which may be outstanding at the time of issuance or
delivery of such securities to substantially the same extent as, or to a greater
extent than, the Securities are so subordinated as provided in this Article.
Nothing contained in this Article 5 or elsewhere in this Indenture or in the
Securities is intended to or shall impair, as among the Company, its creditors
other than holders of Senior Indebtedness and the Holders, the right, which is
absolute and unconditional, of the Holder of any Security to convert such
Security in accordance with Article 4.

     SECTION 5.9. ARTICLE APPLICABLE TO PAYING AGENTS.

     If at any time any Paying Agent other than the Trustee shall have been
appointed by the Company and be then acting hereunder, the term "Trustee" as
used in this Article shall (unless the context otherwise

                                       36
<Page>

requires) be construed as extending to and including such Paying Agent within
its meaning as fully for all intents and purposes as if such Paying Agent were
named in this Article in addition to or in place of the Trustee; PROVIDED,
HOWEVER, that the first paragraph of Section 5.5 shall not apply to the Company
or any Affiliate of the Company if it or such Affiliate acts as Paying Agent.

     SECTION 5.10. SENIOR INDEBTEDNESS ENTITLED TO RELY.

     The holders of Senior Indebtedness (including, without limitation,
Designated Senior Indebtedness) shall have the right to rely upon this Article
5, and no amendment or modification of the provisions contained herein shall
diminish the rights of such holders unless such holders shall have agreed in
writing thereto.

                                    ARTICLE 6
                                    COVENANTS

     SECTION 6.1. PAYMENT OF SECURITIES.

     The Company shall promptly make all payments in respect of the Securities
on the dates and in the manner provided in the Securities and this Indenture. An
installment of principal or interest or Special Interest, if any, shall be
considered paid on the date it is due if the Paying Agent (other than the
Company) holds by 11:00 a.m., New York City time, on that date money, deposited
by the Company or an Affiliate thereof, sufficient to pay the installment. The
Company shall, (in immediately available funds) to the fullest extent permitted
by law, pay interest on overdue principal (including premium, if any) and
overdue installments of interest at the rate borne by the Securities per annum.

     Payment of the principal of (and premium, if any) and any interest on the
Securities shall be made at the office or agency of the Company maintained for
that purpose in the Borough of Manhattan, The City of New York (which shall
initially be State Street Bank and Trust Company, N.A., an Affiliate of the
Trustee, as agent of the Trustee) or at the Corporate Trust Office of the
Trustee in such coin or currency of the United States of America as at the time
of payment is legal tender for payment of public and private debts; PROVIDED,
HOWEVER, that at the option of the Company payment of interest may be made by
check mailed to the address of the Person entitled thereto as such address
appears in the Register; PROVIDED FURTHER that a Holder with an aggregate
principal amount in excess of $2,000,000 will be paid by wire transfer in
immediately available funds at the election of such Holder if such Holder has
provided wire transfer instructions to the Company at least 10 Business Days
prior to the payment date.

     SECTION 6.2. SEC REPORTS.

     The Company shall file all reports and other information and documents
which it is required to file with the SEC pursuant to Section 13 or 15(d) of the
Exchange Act, and within 15 days after it files them with the SEC, the Company
shall file copies of all such reports, information and other documents with the
Trustee.

     Delivery of such reports, information and documents to the Trustee is for
informational purposes only and the Trustee's receipt of such shall not
constitute constructive notice of any information contained therein or
determinable from information contained therein, including the Company's
compliance with any of its covenants hereunder (as to which the Trustee is
entitled to rely exclusively on Officers' Certificates).

                                       37
<Page>

     SECTION 6.3. COMPLIANCE CERTIFICATES.

     The Company shall deliver to the Trustee, within 90 days after the end of
each fiscal year of the Company (beginning with the fiscal year ending December
31, 2001), an Officers' Certificate as to the signer's knowledge of the
Company's compliance with all conditions and covenants on its part contained in
this Indenture and stating whether or not the signer knows of any default or
Event of Default. If such signer knows of such a default or Event of Default,
the Officers' Certificate shall describe the default or Event of Default and the
efforts to remedy the same. For the purposes of this Section 6.3, compliance
shall be determined without regard to any grace period or requirement of notice
provided pursuant to the terms of this Indenture.

     SECTION 6.4. FURTHER INSTRUMENTS AND ACTS.

     Upon request of the Trustee, the Company will execute and deliver such
further instruments and do such further acts as may be reasonably necessary or
proper to carry out more effectively the purposes of this Indenture.

     SECTION 6.5. MAINTENANCE OF CORPORATE EXISTENCE.

     Subject to Article 7, the Company will do or cause to be done all things
necessary to preserve and keep in full force and effect its corporate existence.

     SECTION 6.6. RULE 144A INFORMATION REQUIREMENT.

     Within the period prior to the expiration of the holding period applicable
to sales thereof under Rule 144(k) under the Securities Act (or any successor
provision), the Company covenants and agrees that it shall, during any period in
which it is not subject to Section 13 or 15(d) under the Exchange Act, upon the
request of any Holder or beneficial holder of the Securities make available to
such Holder or beneficial holder of Securities or any Common Stock issued upon
conversion thereof which continue to be Transfer Restricted Securities in
connection with any sale thereof and any prospective purchaser of Securities or
such Common Stock designated by such Holder or beneficial holder, the
information required pursuant to Rule 144A(d)(4) under the Securities Act or
such Common Stock and it will take such further action as any Holder or
beneficial holder of such Securities or such Common Stock may reasonably
request, all to the extent required from time to time to enable such Holder or
beneficial holder to sell its Securities or Common Stock without registration
under the Securities Act within the limitation of the exemption provided by Rule
144A, as such Rule may be amended from time to time. Upon the request of any
Holder or any beneficial holder of the Securities or such Common Stock, the
Company will deliver to such Holder a written statement as to whether it has
complied with such requirements.

     SECTION 6.7. STAY, EXTENSION AND USURY LAWS.

     The Company covenants (to the extent that it may lawfully do so) that it
shall not at any time insist upon, plead, or in any manner whatsoever claim or
take the benefit or advantage of, any stay, extension or usury law or other law
which would prohibit or forgive the Company from paying all or any portion of
the principal of, premium, if any, or interest (including Special Interest, if
any) on the Securities as contemplated herein, wherever enacted, now or at any
time hereafter in force, or which may affect the covenants or the performance of
this Indenture, and the Company (to the extent it may lawfully do so) hereby
expressly waives all benefit or advantage of any such law and covenants that it
will not, by resort to any such law, hinder, delay

                                       38
<Page>

or impede the execution of any power herein granted to the Trustee, but will
suffer and permit the execution of every such power as though no such law had
been enacted.

     SECTION 6.8. PAYMENT OF SPECIAL INTEREST.

     If Special Interest is payable by the Company pursuant to the Registration
Rights Agreement, the Company shall deliver to the Trustee a certificate to that
effect stating (i) the amount of such Special Interest that is payable and (ii)
the date on which such Special Interest is payable. Unless and until a Trust
Officer of the Trustee receives such a certificate, the Trustee may assume
without inquiry that no such Special Interest is payable. If the Company has
paid Special Interest directly to the Persons entitled to it, the Company shall
deliver to the Trustee a certificate setting forth the particulars of such
payment.

                                    ARTICLE 7
              CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER OR LEASE

     SECTION 7.1. COMPANY MAY CONSOLIDATE, ETC, ONLY ON CERTAIN TERMS.

     The Company shall not consolidate with or merge into any other Person (in a
transaction in which the Company is not the surviving corporation) or convey,
transfer or lease its properties and assets substantially as an entirety to any
Person, unless:

          (1) in case the Company shall consolidate with or merge into another
Person (in a transaction in which the Company is not the surviving corporation)
or convey, transfer or lease its properties and assets substantially as an
entirety to any Person, the Person formed by such consolidation or into which
the Company is merged or the Person which acquires by conveyance or transfer, or
which leases, the properties and assets of the Company substantially as an
entirety shall be a corporation organized and validly existing under the laws of
the United States of America, any State thereof or the District of Columbia and
shall expressly assume, by an indenture supplemental hereto, executed and
delivered to the Trustee, in form satisfactory to the Trustee, the due and
punctual payment of the principal of and any premium and interest on all the
Securities and the performance or observance of every covenant of this Indenture
on the part of the Company to be performed or observed and the conversion rights
shall be provided for in accordance with Article 4, by supplemental indenture
satisfactory in form to the Trustee, executed and delivered to the Trustee, by
the Person (if other than the Company) formed by such consolidation or into
which the Company shall have been merged or by the Person which shall have
acquired the Company's assets;

          (2) immediately after giving effect to such transaction, no Event of
Default, and no event which, after notice or lapse of time or both, would become
an Event of Default, shall have happened and be continuing; and

          (3) the Company has delivered to the Trustee an Officers' Certificate
and an Opinion of Counsel, each stating that such consolidation, merger,
conveyance, transfer or lease and, if a supplemental indenture is required in
connection with such transaction, such supplemental indenture comply with this
Article and that all conditions precedent herein provided for relating to such
transaction have been complied with.

                                       39
<Page>

     SECTION 7.2. SUCCESSOR SUBSTITUTED.

     Upon any consolidation of the Company with, or merger of the Company into,
any other Person or any conveyance, transfer or lease of the properties and
assets of the Company substantially as an entirety in accordance with Section
7.1, the successor Person formed by such consolidation or into which the Company
is merged or to which such conveyance, transfer or lease is made shall succeed
to, and be substituted for, and may exercise every right and power of, the
Company under this Indenture with the same effect as if such successor Person
had been named as the Company herein, and thereafter, except in the case of a
lease, the predecessor Person shall be relieved of all obligations and covenants
under this Indenture and the Securities.

                                    ARTICLE 8
                              DEFAULT AND REMEDIES

     SECTION 8.1. EVENTS OF DEFAULT.

     An "Event of Default" shall occur if:

          (1) the Company defaults in the payment of any interest or Special
Interest, if any, on any Security when the same becomes due and payable and the
default continues for a period of 30 days, whether or not such payment shall be
prohibited by the provisions of Article 5 hereof;

          (2) the Company defaults in the payment of any principal of
(including, without limitation, any premium, if any, on) any Security when the
same becomes due and payable (whether at maturity, upon redemption, on a Change
of Control Purchase Date or otherwise), whether or not such payment shall be
prohibited by the provisions of Article 5 hereof;

          (3) the Company fails to comply with any of its other agreements
contained in the Securities or this Indenture and the default continues for the
period and after the notice specified below;

          (4) the Company defaults in the payment of the purchase price of any
Security when the same becomes due and payable, whether or not such payment
shall be prohibited by the provisions of Article 5 hereof;

          (5) the Company fails to provide a Purchase Offer when required by
Section 3.8 for a period of 30 days after notice of failure to do so; or

          (6) any indebtedness under any bond, debenture, note or other evidence
of indebtedness for money borrowed by the Company or any Significant Subsidiary
(all or substantially all of the outstanding voting securities of which are
owned, directly or indirectly, by the Company) or under any mortgage, indenture
or instrument under which there may be issued or by which there may be secured
or evidenced any indebtedness for money borrowed by the Company or any
Significant Subsidiary (all or substantially all of the outstanding voting
securities of which are owned, directly or indirectly, by the Company) (an
"Instrument") with a principal amount then outstanding in excess of U.S.
$35,000,000, whether such indebtedness now exists or shall hereafter be created,
is not paid at final maturity of the Instrument (either at its stated maturity
or upon acceleration thereof), and such indebtedness is not discharged, or such
acceleration is not rescinded or annulled, within a period of 30 days after
there shall have been given, by registered or certified mail, to the Company by
the Trustee or to the Company and the Trustee by the Holders of at least 25% in
aggregate principal amount of the Outstanding Securities a written notice
specifying such default and

                                       40
<Page>

requiring the Company to cause such indebtedness to be discharged or cause such
default to be cured or waived or such acceleration to be rescinded or annulled
and stating that such notice is a "Notice of Default" hereunder; or

          (7) the Company or any Significant Subsidiary, pursuant to or within
the meaning of any Bankruptcy Law:

               (A) commences a voluntary case or proceeding;

               (B) consents to the entry of an order for relief against it in
                    an involuntary case or proceeding;

               (C) consents to the appointment of a Custodian of it or for all
                    or substantially all of its property; or

               (D) makes a general assignment for the benefit of its creditors;
                    or

          (8) a court of competent jurisdiction enters an order or decree under
any Bankruptcy Law that:

               (A) is for relief against the Company or any Significant
                    Subsidiary in an involuntary case or proceeding;

               (B) appoints a Custodian of the Company or any Significant
                    Subsidiary or for all or substantially all of the property
                    of the Company or any Significant Subsidiary; or

               (C) orders the liquidation of the Company or any Significant
                    Subsidiary;

and in each case the order or decree remains unstayed and in effect for 60
consecutive days.

     The term "Bankruptcy Law" means Title 11 of the United States Code (or any
successor thereto) or any similar federal or state law for the relief of
debtors. The term "Custodian" means any receiver, trustee, assignee, liquidator,
sequestrator or similar official under any Bankruptcy Law.

     A default under clause (3) above is not an Event of Default until the
Trustee notifies the Company, or the Holders of at least 25% in aggregate
principal amount of the Securities then outstanding notify the Company and the
Trustee, in writing of the default, and the Company does not cure the default
within 60 days after receipt of such notice. The notice given pursuant to this
Section 8.1 must specify the default, demand that it be remedied and state that
the notice is a "Notice of Default." When any default under this Section 8.1 is
cured, it ceases.

     The Trustee shall not be charged with knowledge of any Event of Default
unless written notice thereof shall have been given to a Trust Officer at the
Corporate Trust Office of the Trustee by the Company, a Paying Agent, any Holder
or any agent of any Holder.

                                       41
<Page>

     SECTION 8.2. ACCELERATION.

     If an Event of Default (other than an Event of Default specified in clause
(7) or (8) of Section 8.1) occurs and is continuing, the Trustee may, by notice
to the Company, or the Holders of at least 25% in aggregate principal amount of
the Securities then outstanding may, by notice to the Company and the Trustee,
declare all unpaid principal to the date of acceleration on the Securities then
outstanding (if not then due and payable) to be due and payable upon any such
declaration, and the same shall become and be immediately due and payable. If an
Event of Default specified in clause (7) or (8) of Section 8.1 occurs, all
unpaid principal of the Securities then outstanding shall ipso facto become and
be immediately due and payable without any declaration or other act on the part
of the Trustee or any Holder. The Holders of a majority in aggregate principal
amount of the Securities then outstanding by notice to the Trustee may rescind
an acceleration and its consequences if (a) all existing Events of Default,
other than the nonpayment of the principal of the Securities which has become
due solely by such declaration of acceleration, have been cured or waived; (b)
to the extent the payment of such interest is lawful, interest (calculated at
the rate per annum borne by the Securities) on overdue installments of interest
and overdue principal, which has become due otherwise than by such declaration
of acceleration, has been paid; (c) the rescission would not conflict with any
judgment or decree of a court of competent jurisdiction; and (d) all payments
due to the Trustee and any predecessor Trustee under Section 9.7 have been made.
No such rescission shall affect any subsequent default or impair any right
consequent thereto.

     SECTION 8.3. OTHER REMEDIES.

     If an Event of Default occurs and is continuing, the Trustee may, but shall
not be obligated to, pursue any available remedy by proceeding at law or in
equity to collect the payment of the principal of or interest on the Securities
or to enforce the performance of any provision of the Securities or this
Indenture.

     The Trustee may maintain a proceeding even if it does not possess any of
the Securities or does not produce any of them in the proceeding. A delay or
omission by the Trustee or any Securityholder in exercising any right or remedy
accruing upon an Event of Default shall not impair the right or remedy or
constitute a waiver of or acquiescence in the Event of Default. No remedy is
exclusive of any other remedy. All available remedies are cumulative to the
extent permitted by law.

     SECTION 8.4. WAIVER OF DEFAULTS AND EVENTS OF DEFAULT.

     Subject to Sections 8.7 and 11.2, the Holders of a majority in aggregate
principal amount of the Securities then outstanding by notice to the Trustee may
waive an existing default or Event of Default and its consequence, except a
default or Event of Default in the payment of the principal of, premium, if any,
or interest on any Security, a failure by the Company to convert any Securities
into Common Stock or any default or Event of Default in respect of any provision
of this Indenture or the Securities which, under Section 11.2, cannot be
modified or amended without the consent of the Holder of each Security affected.
When a default or Event of Default is waived, it is cured and ceases.

     SECTION 8.5. CONTROL BY MAJORITY.

     The Holders of a majority in aggregate principal amount of the Securities
then outstanding may direct the time, method and place of conducting any
proceeding for any remedy available to the Trustee or exercising any trust or
power conferred on it. However, the Trustee may refuse to follow any direction
that conflicts with law or this Indenture, that the Trustee determines may be
unduly prejudicial to the rights of

                                       42
<Page>

another Holder or the Trustee, or that may involve the Trustee in personal
liability unless the Trustee is offered indemnity satisfactory to it; PROVIDED,
HOWEVER, that the Trustee may take any other action deemed proper by the Trustee
which is not inconsistent with such direction.

     SECTION 8.6. LIMITATIONS ON SUITS.

     A Holder may not pursue any remedy with respect to this Indenture or the
Securities (except actions for payment of overdue principal or interest or for
the conversion of the Securities pursuant to Article 4) unless:

          (1) the Holder gives to the Trustee written notice of a continuing
Event of Default;

          (2) the Holders of at least 25% in aggregate principal amount of the
then outstanding Securities make a written request to the Trustee to pursue the
remedy;

          (3) such Holder or Holders offer to the Trustee reasonable indemnity
to the Trustee against any loss, liability or expense;

          (4) the Trustee does not comply with the request within 60 days after
receipt of the request and the offer of indemnity; and

          (5) no direction inconsistent with such written request has been given
to the Trustee during such 60-day period by the Holders of a majority in
aggregate principal amount of the Securities then outstanding.

     A Securityholder may not use this Indenture to prejudice the rights of
another Securityholder or to obtain a preference or priority over such other
Securityholder.

     SECTION 8.7. RIGHTS OF HOLDERS TO RECEIVE PAYMENT AND TO CONVERT.

     Notwithstanding any other provision of this Indenture, the right of any
Holder of a Security to receive payment of the principal of and interest on the
Security, on or after the respective due dates expressed in the Security and
this Indenture, to convert such Security in accordance with Article 4 and to
bring suit for the enforcement of any such payment on or after such respective
dates or the right to convert, is absolute and unconditional and shall not be
impaired or affected without the consent of the Holder.

     SECTION 8.8. COLLECTION SUIT BY TRUSTEE.

     If an Event of Default in the payment of principal or interest specified in
clause (1) or (2) of Section 8.1 occurs and is continuing, the Trustee may
recover judgment in its own name and as trustee of an express trust against the
Company or another obligor on the Securities for the whole amount of principal
and accrued interest remaining unpaid, together with, to the extent that payment
of such interest is lawful, interest on overdue principal and on overdue
installments of interest, in each case at the rate per annum borne by the
Securities and such further amount as shall be sufficient to cover the costs and
expenses of collection, including the reasonable compensation, expenses,
disbursements and advances of the Trustee, its agents and counsel.

                                       43
<Page>

     SECTION 8.9. TRUSTEE MAY FILE PROOFS OF CLAIM.

     The Trustee may file such proofs of claim and other papers or documents as
may be necessary or advisable in order to have the claims of the Trustee
(including any claim for the reasonable compensation, expenses, disbursements
and advances of the Trustee, its agents and counsel) and the Holders allowed in
any judicial proceedings relative to the Company (or any other obligor on the
Securities), its creditors or its property and shall be entitled and empowered
to collect and receive any money or other property payable or deliverable on any
such claims and to distribute the same, and any Custodian in any such judicial
proceeding is hereby authorized by each Holder to make such payments to the
Trustee and, in the event that the Trustee shall consent to the making of such
payments directly to the Holders, to pay to the Trustee any amount due to it for
the reasonable compensation, expenses, disbursements and advances of the
Trustee, its agents and counsel, and any other amounts due the Trustee under
Section 9.7, and to the extent that such payment of the reasonable compensation,
expenses, disbursements and advances in any such proceedings shall be denied for
any reason, payment of the same shall be secured by a lien on, and shall be paid
out of, any and all distributions, dividends, money, securities and other
property which the Holders may be entitled to receive in such proceedings,
whether in liquidation or under any plan of reorganization or arrangement or
otherwise. Nothing herein contained shall be deemed to authorize the Trustee to
authorize or consent to, or, on behalf of any Holder, to authorize, accept or
adopt any plan of reorganization, arrangement, adjustment or composition
affecting the Securities or the rights of any Holder thereof, or to authorize
the Trustee to vote in respect of the claim of any Holder in any such
proceeding.

     SECTION 8.10. PRIORITIES.

     If the Trustee collects any money pursuant to this Article 8, it shall pay
out the money in the following order:

     First, to the Trustee for amounts due under Section 9.7;

     Second, to the holders of Senior Indebtedness to the extent required by
Article 5;

     Third, to Holders for amounts due and unpaid on the Securities for
principal and interest (including Special Interest, if any), ratably, without
preference or priority of any kind, according to the amounts due and payable on
the Securities for principal and interest (including Special Interest, if any),
respectively; and

     Fourth, the balance, if any, to the Company.

     The Trustee may fix a record date and payment date for any payment to
Holders pursuant to this Section 8.10.

     SECTION 8.11. UNDERTAKING FOR COSTS.

     In any suit for the enforcement of any right or remedy under this Indenture
or in any suit against the Trustee for any action taken or omitted by it as
Trustee, a court in its discretion may require the filing by any party litigant
in the suit of an undertaking to pay the costs of the suit, and the court in its
discretion may assess reasonable costs, including reasonable attorneys' fees and
expenses, against any party litigant in the suit, having due regard to the
merits and good faith of the claims or defenses made by the party litigant. This
Section 8.11 does not apply to a suit made by the Trustee, a suit by a Holder
pursuant to Section 8.7, or a suit by Holders of more than 10% in aggregate
principal amount of the Securities then outstanding.

                                       44
<Page>

                                    ARTICLE 9
                                     TRUSTEE

     SECTION 9.1. DUTIES OF TRUSTEE.

     (a) If an Event of Default has occurred and is continuing, the Trustee
shall exercise such of the rights and powers vested in it by this Indenture and
use the same degree of care and skill in its exercise as a prudent person would
exercise or use under the circumstances in the conduct of his or her own
affairs.

     (b) Except during the continuance of an Event of Default:

          (1) the Trustee need perform only those duties as are specifically set
forth in this Indenture and no others; and

          (2) in the absence of bad faith on its part, the Trustee may
conclusively rely, as to the truth of the statements and the correctness of the
opinions expressed therein, upon certificates or opinions furnished to the
Trustee and conforming to the requirements of this Indenture. The Trustee,
however, shall examine any certificates and opinions which by any provision
hereof are specifically required to be delivered to the Trustee to determine
whether or not they conform to the requirements of this Indenture.

     (c) The Trustee may not be relieved from liability for its own negligent
action, its own negligent failure to act, or its own willful misconduct, except
that:

          (1) this paragraph does not limit the effect of subsection (b) of this
Section 9.1;

          (2) the Trustee shall not be liable for any error of judgment made in
good faith by a Trust Officer, unless it is proved that the Trustee was
negligent in ascertaining the pertinent facts; and

          (3) the Trustee shall not be liable with respect to any action it
takes or omits to take in good faith in accordance with a direction received by
it pursuant to Section 8.5.

     (d) No provision of this Indenture shall require the Trustee to expend or
risk its own funds or otherwise incur any financial liability in the performance
of any of its duties hereunder or in the exercise of any of its rights or powers
unless the Trustee shall have received adequate indemnity in its opinion against
potential costs and liabilities incurred by it relating thereto.

     (e) Every provision of this Indenture that in any way relates to the
Trustee is subject to subsections (a), (b), (c) and (d) of this Section 9.1.

     (f) The Trustee shall not be liable for interest on any money received by
it except as the Trustee may agree in writing with the Company. Money held in
trust by the Trustee need not be segregated from other funds except to the
extent required by law.

     SECTION 9.2. RIGHTS OF TRUSTEE.

     Subject to Section 9.1:

                                       45
<Page>

     (a) The Trustee may rely conclusively on any document believed by it to be
genuine and to have been signed or presented by the proper person. The Trustee
need not investigate any fact or matter stated in the document.

     (b) Before the Trustee acts or refrains from acting, it may require an
Officers' Certificate or an Opinion of Counsel, which shall conform to Section
12.4(b). The Trustee shall not be liable for any action it takes or omits to
take in good faith in reliance on such Officers' Certificate or Opinion.

     (c) The Trustee may act through its agents and shall not be responsible for
the misconduct or negligence of any agent appointed with due care.

     (d) The Trustee shall not be liable for any action it takes or omits to
take in good faith which it believes to be authorized or within its rights or
powers.

     (e) The Trustee may consult with counsel of its selection, and the advice
or opinion of such counsel as to matters of law shall be full and complete
authorization and protection in respect of any such action taken, omitted or
suffered by it hereunder in good faith and in accordance with the advice or
opinion of such counsel.

     (f) The Trustee shall be under no obligation to exercise any of the rights
or powers vested in it by this Indenture at the request or direction of any of
the Holders pursuant to this Indenture, unless such Holders shall have offered
to the Trustee security or indemnity satisfactory to the Trustee against the
costs, expenses and liabilities which might be incurred by it in compliance with
such request or direction.

     (g) The Trustee shall not be bound to make any investigation into the facts
or matters stated in any resolution, certificate, statement, instrument,
opinion, report, notice, request, direction, consent, order, bond, debenture,
note, other evidence of indebtedness or other paper or document, but the
Trustee, in its discretion, may make such further inquiry or investigation into
such facts or matters as it may see fit, and, if the Trustee shall determine to
make such further inquiry or investigation, it shall be entitled to examine the
books, records and premises of the Company, personally or by agent or attorney
at the sole cost of the Company and shall incur no liability or additional
liability of any kind by reason of such inquiry or investigation.

     (h) The Trustee shall not be deemed to have notice of any Default or Event
of Default unless a Trust Officer of the Trustee has actual knowledge thereof or
unless written notice of any event which is in fact such a default is received
by the Trustee at the Corporate Trust Office, and such notice references the
Securities and this Indenture.

     (i) The rights, privileges, protections, immunities and benefits given to
the Trustee, including, without limitation, its right to be indemnified, are
extended to, and shall be enforceable by, the Trustee in each of its capacities
hereunder, and to each agent, custodian and other Person employed to act
hereunder.

     SECTION 9.3. INDIVIDUAL RIGHTS OF TRUSTEE.

     The Trustee in its individual or any other capacity may become the owner or
pledgee of Securities and may otherwise deal with the Company or an Affiliate of
the Company with the same rights it would have if it were not Trustee. Any Agent
may do the same with like rights. However, the Trustee is subject to Sections
9.10 and 9.11.

                                       46
<Page>

     SECTION 9.4. TRUSTEE'S DISCLAIMER.

     The Trustee makes no representation as to the validity or adequacy of this
Indenture or the Securities, it shall not be accountable for the Company's use
of the proceeds from the Securities, and it shall not be responsible for any
statement in the Securities other than its certificate of authentication.

     SECTION 9.5. NOTICE OF DEFAULT OR EVENTS OF DEFAULT.

     If a default or an Event of Default occurs and is continuing and if it is
known to the Trustee, the Trustee shall mail to each Securityholder notice of
the default or Event of Default within 90 days after it occurs. However, the
Trustee may withhold the notice if and so long as a committee of its Trust
Officers in good faith determines that withholding notice is in the interests of
Securityholders, except in the case of a default or an Event of Default in
payment of the principal of or interest on any Security.

     SECTION 9.6. REPORTS BY TRUSTEE TO HOLDERS.

     If such report is required by TIA Section 313, within 60 days after each
May 15, beginning with the May 15 following the date of this Indenture, the
Trustee shall mail to each Securityholder a brief report dated as of such May 15
that complies with TIA Section 313(a). The Trustee also shall comply with TIA
Section 313(b)(2) and (c).

     A copy of each report at the time of its mailing to Securityholders shall
be mailed to the Company and filed with the SEC and each stock exchange, if any,
on which the Securities are listed. The Company shall notify the Trustee
whenever the Securities become listed on any stock exchange or listed or
admitted to trading on any quotation system and any changes in the stock
exchanges or quotation systems on which the Securities are listed or admitted to
trading and of any delisting thereof.

     SECTION 9.7. COMPENSATION AND INDEMNITY.

     The Company shall pay to the Trustee from time to time such compensation
(as agreed to from time to time by the Company and the Trustee in writing) for
its services (which compensation shall not be limited by any provision of law in
regard to the compensation of a trustee of an express trust). The Company shall
reimburse the Trustee upon request for all reasonable disbursements, expenses
and advances incurred or made by it. Such expenses may include the reasonable
compensation, disbursements and expenses of the Trustee's agents and counsel.

     The Company shall indemnify the Trustee or any predecessor Trustee (which
for purposes of this Section 9.7 shall include its officers, directors,
employees and agents) for, and hold it harmless against, any and all loss,
liability or expense including taxes (other than taxes based upon, measured by
or determined by the income of the Trustee), (including reasonable legal fees
and expenses) incurred by it in connection with the acceptance or administration
of its duties under this Indenture or any action or failure to act as authorized
or within the discretion or rights or powers conferred upon the Trustee
hereunder including the reasonable costs and expenses of the Trustee and its
counsel in defending itself against any claim or liability in connection with
the exercise or performance of any of its powers or duties hereunder. The
Trustee shall notify the Company promptly of any claim asserted against the
Trustee for which it may seek indemnity. The Company need not pay for any
settlement without its written consent, which shall not be unreasonably
withheld.

                                       47
<Page>

     The Company need not reimburse the Trustee for any expense or indemnify it
against any loss or liability incurred by it resulting from its gross negligence
or bad faith.

     To secure the Company's payment obligations in this Section 9.7, the
Trustee shall have a senior claim to which the Securities are hereby made
subordinate on all money or property held or collected by the Trustee, except
such money or property held in trust to pay the principal of and interest on the
Securities. The obligations of the Company under this Section 9.7 shall survive
the satisfaction and discharge of this Indenture or the resignation or removal
of the Trustee.

     When the Trustee incurs expenses or renders services after an Event of
Default specified in clause (7) or (8) of Section 8.1 occurs, the expenses and
the compensation for the services are intended to constitute expenses of
administration under any Bankruptcy Law. The provisions of this Section shall
survive the termination of this Indenture.

     SECTION 9.8. REPLACEMENT OF TRUSTEE.

     The Trustee may resign by so notifying the Company. The Holders of a
majority in aggregate principal amount of the Securities then outstanding may
remove the Trustee by so notifying the Trustee and may, with the Company's
written consent, appoint a successor Trustee. The Company may remove the Trustee
if:

          (1) the Trustee fails to comply with Section 9.10;

          (2) the Trustee is adjudged a bankrupt or an insolvent;

          (3) a receiver or other public officer takes charge of the Trustee or
its property; or

          (4) the Trustee becomes incapable of acting.

     If the Trustee resigns or is removed or if a vacancy exists in the office
of Trustee for any reason, the Company shall promptly appoint a successor
Trustee. The resignation or removal of a Trustee shall not be effective until a
successor Trustee shall have delivered the written acceptance of its appointment
as described below.

     If a successor Trustee does not take office within 45 days after the
retiring Trustee resigns or is removed, the retiring Trustee, the Company or the
Holders of 10% in principal amount of the Securities then outstanding may
petition any court of competent jurisdiction for the appointment of a successor
Trustee at the expense of the Company.

     If the Trustee fails to comply with Section 9.10, any Holder may petition
any court of competent jurisdiction for the removal of the Trustee and the
appointment of a successor Trustee.

     A successor Trustee shall deliver a written acceptance of its appointment
to the retiring Trustee and to the Company. Immediately after that, the retiring
Trustee shall transfer all property held by it as Trustee to the successor
Trustee and be released from its obligations (exclusive of any liabilities that
the retiring Trustee may have incurred while acting as Trustee) hereunder, the
resignation or removal of the retiring Trustee shall become effective, and the
successor Trustee shall have all the rights, powers and duties of the Trustee
under this Indenture. A successor Trustee shall mail notice of its succession to
each Holder.

                                       48
<Page>

     A retiring Trustee shall not be liable for the acts or omissions of any
successor Trustee after its succession.

     Notwithstanding replacement of the Trustee pursuant to this Section 9.8,
the Company's obligations under Section 9.7 shall continue for the benefit of
the retiring Trustee.

     SECTION 9.9. SUCCESSOR TRUSTEE BY MERGER, ETC.

     If the Trustee consolidates with, merges or converts into, or transfers all
or substantially all of its corporate trust assets (including the administration
of this Indenture) to, another corporation, the resulting, surviving or
transferee corporation, without any further act, shall be the successor Trustee,
PROVIDED such transferee corporation shall qualify and be eligible under Section
9.10. Such successor Trustee shall promptly mail notice of its succession to the
Company and each Holder.

     SECTION 9.10. ELIGIBILITY; DISQUALIFICATION.

     The Trustee shall always satisfy the requirements of paragraphs (1), (2)
and (5) of TIA Section 310(a). The Trustee (or its parent holding company) shall
have a combined capital and surplus of at least $50,000,000. If at any time the
Trustee shall cease to satisfy any such requirements, it shall resign
immediately in the manner and with the effect specified in this Article 9. The
Trustee shall be subject to the provisions of TIA Section 310(b). Nothing herein
shall prevent the Trustee from filing with the SEC the application referred to
in the penultimate paragraph of TIA Section 310(b).

     SECTION 9.11. PREFERENTIAL COLLECTION OF CLAIMS AGAINST COMPANY.

     The Trustee shall comply with TIA Section 311(a), excluding any creditor
relationship listed in TIA Section 311(b). A Trustee who has resigned or been
removed shall be subject to TIA Section 311(a) to the extent indicated therein.

                                   ARTICLE 10
                     SATISFACTION AND DISCHARGE OF INDENTURE

     SECTION 10.1. SATISFACTION AND DISCHARGE OF INDENTURE.

     This Indenture shall cease to be of further effect (except as to any
surviving rights of conversion, registration of transfer or exchange of
Securities herein expressly provided for and except as further provided below),
and the Trustee, on demand of and at the expense of the Company, shall execute
proper instruments acknowledging satisfaction and discharge of this Indenture,
when

          (1) either

               (A) all Securities theretofore authenticated and delivered (other
than (i) Securities which have been destroyed, lost or stolen and which have
been replaced or paid as provided in Section 2.7 and (ii) Securities for whose
payment money has theretofore been deposited in trust and thereafter repaid to
the Company as provided in Section 10.3) have been delivered to the Trustee for
cancellation; or

               (B) all such Securities not theretofore delivered to the Trustee
for cancellation

                                       49
<Page>

                    (i)   have become due and payable, or

                    (ii)  will become due and payable at the Final Maturity Date
within one year, or

                    (iii) are to be called for redemption within one year under
arrangements satisfactory to the Trustee for the giving of notice of redemption
by the Trustee in the name, and at the expense, of the Company,

and the Company, in the case of clause (i), (ii) or (iii) above, has irrevocably
deposited or caused to be irrevocably deposited with the Trustee or a Paying
Agent (other than the Company or any of its Affiliates) as trust funds in trust
for the purpose cash in an amount sufficient to pay and discharge the entire
indebtedness on such Securities not theretofore delivered to the Trustee for
cancellation, for principal and interest (including Special Interest, if any) to
the date of such deposit (in the case of Securities which have become due and
payable) or to the Final Maturity Date or Redemption Date, as the case may be;

          (2) the Company has paid or caused to be paid all other sums payable
hereunder by the Company; and

          (3) the Company has delivered to the Trustee an Officers' Certificate
and an Opinion of Counsel, each stating that all conditions precedent herein
provided for relating to the satisfaction and discharge of this Indenture have
been complied with.

     Notwithstanding the satisfaction and discharge of this Indenture, the
obligations of the Company to the Trustee under Section 9.7 shall survive and,
if money shall have been deposited with the Trustee pursuant to subclause (B) of
clause (1) of this Section, the provisions of Sections 2.3, 2.4, 2.5, 2.6, 2.7,
2.12, 3.8, 3.9, 3.10, 3.11, 3.12, 3.13 and 12.5, Article 4, the last paragraph
of Section 6.2 and this Article 10, shall survive until the Securities have been
paid in full.

     SECTION 10.2. APPLICATION OF TRUST MONEY.

     Subject to the provisions of Section 10.3, the Trustee or a Paying Agent
shall hold in trust, for the benefit of the Holders, all money deposited with it
pursuant to Section 10.1 and shall apply the deposited money in accordance with
this Indenture and the Securities to the payment of the principal of and
interest on the Securities. Money so held in trust shall not be subject to the
subordination provisions of Article 5.

     SECTION 10.3. REPAYMENT TO COMPANY.

     The Trustee and each Paying Agent shall promptly pay to the Company upon
request any excess money (i) deposited with them pursuant to Section 10.1 and
(ii) held by them at any time.

     The Trustee and each Paying Agent shall pay to the Company upon request any
money held by them for the payment of principal or interest that remains
unclaimed for two years after a right to such money has matured; PROVIDED,
HOWEVER, that the Trustee or such Paying Agent, before being required to make
any such payment, may at the expense of the Company cause to be mailed to each
Holder entitled to such money notice that such money remains unclaimed and that
after a date specified therein, which shall be at least 30 days from the date of
such mailing, any unclaimed balance of such money then remaining will be repaid
to the Company. After payment to the Company, Holders entitled to money must
look to the Company for payment as general creditors unless an applicable
abandoned property law designates another person.

                                       50
<Page>

     SECTION 10.4. REINSTATEMENT.

     If the Trustee or any Paying Agent is unable to apply any money in
accordance with Section 10.2 by reason of any legal proceeding or by reason of
any order or judgment of any court or governmental authority enjoining,
restraining or otherwise prohibiting such application, then the Company's
obligations under this Indenture and the Securities shall be revived and
reinstated as though no deposit had occurred pursuant to Section 10.1 until such
time as the Trustee or such Paying Agent is permitted to apply all such money in
accordance with Section 10.2; PROVIDED, HOWEVER, that if the Company has made
any payment of the principal of or interest on any Securities because of the
reinstatement of its obligations, the Company shall be subrogated to the rights
of the Holders of such Securities to receive any such payment from the money
held by the Trustee or such Paying Agent.

                                   ARTICLE 11
                       AMENDMENTS, SUPPLEMENTS AND WAIVERS

     SECTION 11.1. WITHOUT CONSENT OF HOLDERS.

     The Company and the Trustee may amend or supplement this Indenture or the
Securities without notice to or consent of any Securityholder:

     (a)  to comply with Sections 4.11 and 7.1;

     (b)  to cure any ambiguity, defect or inconsistency;

     (c)  to make any other change that does not adversely affect the rights of
any Securityholder;

     (d)  to comply with the provisions of the TIA;

     (e)  to add to the covenants of the Company for the equal and ratable
benefit of the Securityholders or to surrender any right, power or option
conferred upon the Company; or

     (f)  to appoint a successor Trustee.

     SECTION 11.2. WITH CONSENT OF HOLDERS.

     The Company and the Trustee may amend or supplement this Indenture or the
Securities with the written consent of the Holders of at least a majority in
aggregate principal amount of the Securities then outstanding. The Holders of at
least a majority in aggregate principal amount of the Securities then
outstanding may waive compliance in a particular instance by the Company with
any provision of this Indenture or the Securities without notice to any
Securityholder. However, notwithstanding the foregoing but subject to Section
11.4, without the written consent of each Securityholder affected, an amendment,
supplement or waiver, including a waiver pursuant to Section 8.4, may not:

     (a) change the stated maturity of the principal of, or interest on, any
Security;

     (b) reduce the principal amount of, or any premium or interest on, any
Security;

     (c) reduce the amount of principal payable upon acceleration of the
maturity of any Security;

                                       51
<Page>

     (d) change the place or currency of payment of principal of, or any premium
or interest on, any Security;

     (e) impair the right to institute suit for the enforcement of any payment
on, or with respect to, any Security;

     (f) modify the provisions with respect to the purchase right of Holders
pursuant to Article 3 upon a Change in Control in a manner adverse to Holders;

     (g) modify the subordination provisions of Article 5 in a manner materially
adverse to the Holders of Securities;

     (h) adversely affect the right of Holders to convert Securities other than
as provided in or under Article 4 of this Indenture;

     (i) reduce the percentage of the aggregate principal amount of the
outstanding Securities whose Holders must consent to a modification or
amendment;

     (j) reduce the percentage of the aggregate principal amount of the
outstanding Securities necessary for the waiver of compliance with certain
provisions of this Indenture or the waiver of certain defaults under this
Indenture; and

     (k) modify any of the provisions of this Section or Section 8.4, except to
increase any such percentage or to provide that certain provisions of this
Indenture cannot be modified or waived without the consent of the Holder of each
outstanding Security affected thereby.

     It shall not be necessary for the consent of the Holders under this Section
11.2 to approve the particular form of any proposed amendment, supplement or
waiver, but it shall be sufficient if such consent approves the substance
thereof.

     After an amendment, supplement or waiver under this Section 11.2 becomes
effective, the Company shall mail to the Holders affected thereby a notice
briefly describing the amendment, supplement or waiver. Any failure of the
Company to mail such notice, or any defect therein, shall not, however, in any
way impair or affect the validity of any such amendment, supplement or waiver.
An amendment or supplement under this Section 11.2 or under Section 11.1 may not
make any change that adversely affects the rights under Article 5 of any holder
of an issue of Senior Indebtedness unless the holders of that issue, pursuant to
its terms, consent to the change.

     To the extent that the Company or any of the Subsidiaries hold any
Securities, such Securities shall be disregarded for purposes of voting in
connection with any notice, waiver, consent or direction requiring the vote or
concurrence of Securityholders.

     SECTION 11.3. COMPLIANCE WITH TRUST INDENTURE ACT.

     Every amendment to or supplement of this Indenture or the Securities shall
comply with the TIA as in effect at the date of such amendment or supplement.

                                       52
<Page>

     SECTION 11.4. REVOCATION AND EFFECT OF CONSENTS.

     Until an amendment, supplement or waiver becomes effective, a consent to it
by a Holder is a continuing consent by the Holder and every subsequent Holder of
a Security or portion of a Security that evidences the same debt as the
consenting Holder's Security, even if notation of the consent is not made on any
Security. However, any such Holder or subsequent Holder may revoke the consent
as to its Security or portion of a Security if the Trustee receives the notice
of revocation before the date the amendment, supplement or waiver becomes
effective.

     After an amendment, supplement or waiver becomes effective, it shall bind
every Securityholder, unless it makes a change described in any of clauses (a)
through (k) of Section 11.2. In that case the amendment, supplement or waiver
shall bind each Holder of a Security who has consented to it and every
subsequent Holder of a Security or portion of a Security that evidences the same
debt as the consenting Holder's Security.

     SECTION 11.5. NOTATION ON OR EXCHANGE OF SECURITIES.

     If an amendment, supplement or waiver changes the terms of a Security, the
Trustee may require the Holder of the Security to deliver it to the Trustee. The
Trustee may place an appropriate notation on the Security about the changed
terms and return it to the Holder. Alternatively, if the Company or the Trustee
so determines, the Company in exchange for the Security shall issue and the
Trustee shall authenticate a new Security that reflects the changed terms.

     SECTION 11.6. TRUSTEE TO SIGN AMENDMENTS, ETC.

     The Trustee shall sign any amendment or supplemental indenture authorized
pursuant to this Article 11 if the amendment or supplemental indenture does not
adversely affect the rights, duties, liabilities or immunities of the Trustee.
If it does, the Trustee may, in its sole discretion, but need not sign it. In
signing or refusing to sign such amendment or supplemental indenture, the
Trustee shall be entitled to receive and, subject to Section 9.1, shall be fully
protected in relying upon, an Opinion of Counsel stating that such amendment or
supplemental indenture is authorized or permitted by this Indenture. The Company
may not sign an amendment or supplement indenture until the Board of Directors
approves it.

     SECTION 11.7. EFFECT OF SUPPLEMENTAL INDENTURES.

     Upon the execution of any supplemental indenture under this Article, this
Indenture shall be modified in accordance therewith, and such supplemental
indenture shall form a part of this Indenture for all purposes; and every Holder
of Securities theretofore or thereafter authenticated and delivered hereunder
shall be bound thereby.

                                   ARTICLE 12
                                  MISCELLANEOUS

     SECTION 12.1. TRUST INDENTURE ACT CONTROLS.

     If any provision of this Indenture limits, qualifies or conflicts with the
duties imposed by any of Sections 310 to 317, inclusive, of the TIA through
operation of Section 318(c) thereof, such imposed duties shall control.

                                       53
<Page>

     SECTION 12.2. NOTICES.

     Any demand, authorization notice, request, consent or communication shall
be given in writing and delivered in person or mailed by first-class mail,
postage prepaid, addressed as follows or transmitted by facsimile transmission
(confirmed by delivery in person or mail by first-class mail, postage prepaid,
or by guaranteed overnight courier) to the following facsimile numbers:

          If to the Company, to:
          Invitrogen Corporation
          1600 Faraday Avenue
          Carlsbad, CA 92008
          Attention: Chief Financial Officer
          Facsimile No.: (760) 602-6505

          with a copy to:
          Invitrogen Corporation
          1600 Faraday Avenue
          Carlsbad, CA 92008
          Attention: General Counsel
          Facsimile No.: (760) 476-6326

          if to the Trustee, to:
          State Street Bank and Trust Company of California, N.A.
          633 West 5th Street, 12th Floor
          Los Angeles, California  90071
          Attn:  Corporate Trust Department (Invitrogen Corporation--2 1/4%
          Convertible Subordinated Notes due 2006)
          Facsimile No.: (213) 362-7357

     Such notices or communications shall be effective when received.

     The Company or the Trustee by notice to the other may designate additional
or different addresses for subsequent notices or communications.

     Any notice or communication mailed to a Securityholder shall be mailed by
first-class mail or delivered by an overnight delivery service to it at its
address shown on the register kept by the Primary Registrar.

     Failure to mail a notice or communication to a Securityholder or any defect
in it shall not affect its sufficiency with respect to other Securityholders. If
a notice or communication to a Securityholder is mailed in the manner provided
above, it is duly given, whether or not the addressee receives it.

     SECTION 12.3. COMMUNICATIONS BY HOLDERS WITH OTHER HOLDERS.

     Securityholders may communicate pursuant to TIA Section 312(b) with other
Securityholders with respect to their rights under this Indenture or the
Securities. The Company, the Trustee, the Registrar and any other person shall
have the protection of TIA Section 312(c).

                                       54
<Page>

     SECTION 12.4. CERTIFICATE AND OPINION AS TO CONDITIONS PRECEDENT.

     (a) Upon any request or application by the Company to the Trustee to take
any action under this Indenture, the Company shall furnish to the Trustee at the
request of the Trustee:

          (1) an Officers' Certificate stating that, in the opinion of the
signers, all conditions precedent (including any covenants, compliance with
which constitutes a condition precedent), if any, provided for in this Indenture
relating to the proposed action have been complied with; and

          (2) an Opinion of Counsel stating that, in the opinion of such
counsel, all such conditions precedent (including any covenants, compliance with
which constitutes a condition precedent) have been complied with.

     (b) Each Officers' Certificate and Opinion of Counsel with respect to
compliance with a condition or covenant provided for in this Indenture shall
include:

          (1) a statement that the person making such certificate or opinion has
read such covenant or condition;

          (2) a brief statement as to the nature and scope of the examination or
investigation upon which the statements or opinions contained in such
certificate or opinion are based;

          (3) a statement that, in the opinion of such person, he or she has
made such examination or investigation as is necessary to enable him or her to
express an informed opinion as to whether or not such covenant or condition has
been complied with; and

          (4) a statement as to whether or not, in the opinion of such person,
such condition or covenant has been complied with;

PROVIDED HOWEVER, that with respect to matters of fact an Opinion of Counsel may
rely on an Officers' Certificate or certificates of public officials.

     SECTION 12.5. RECORD DATE FOR VOTE OR CONSENT OF SECURITYHOLDERS.

     The Company (or, in the event deposits have been made pursuant to Section
10.1, the Trustee) may set a record date for purposes of determining the
identity of Holders entitled to vote or consent to any action by vote or consent
authorized or permitted under this Indenture, which record date shall not be
more than thirty (30) days prior to the date of the commencement of solicitation
of such action. Notwithstanding the provisions of Section 11.4, if a record date
is fixed, those persons who were Holders of Securities at the close of business
on such record date (or their duly designated proxies), and only those persons,
shall be entitled to take such action by vote or consent or to revoke any vote
or consent previously given, whether or not such persons continue to be Holders
after such record date.

                                       55
<Page>

     SECTION 12.6. RULES BY TRUSTEE, PAYING AGENT, REGISTRAR AND CONVERSION
AGENT.

     The Trustee may make reasonable rules (not inconsistent with the terms of
this Indenture) for action by or at a meeting of Holders. Any Registrar, Paying
Agent or Conversion Agent may make reasonable rules for its functions.

     SECTION 12.7. LEGAL HOLIDAYS.

     A "Legal Holiday" is a Saturday, Sunday or a day on which state or
federally chartered banking institutions in New York, New York and the state in
which the Corporate Trust Office is located are not required to be open. If a
payment date is a Legal Holiday, payment shall be made on the next succeeding
day that is not a Legal Holiday, and no interest shall accrue for the
intervening period. If a regular record date is a Legal Holiday, the record date
shall not be affected.

     SECTION 12.8. GOVERNING LAW.

     This Indenture and the Securities shall be governed by, and construed in
accordance with, the laws of the State of New York, without regard to principles
of conflicts of laws.

     SECTION 12.9. NO ADVERSE INTERPRETATION OF OTHER AGREEMENTS.

     This Indenture may not be used to interpret another indenture, loan or debt
agreement of the Company or a Subsidiary of the Company. Any such indenture,
loan or debt agreement may not be used to interpret this Indenture.

     SECTION 12.10. NO RECOURSE AGAINST OTHERS.

     All liability described in paragraph 19 of the Securities of any director,
officer, employee or shareholder, as such, of the Company is waived and
released.

     SECTION 12.11. SUCCESSORS.

     All agreements of the Company in this Indenture and the Securities shall
bind its successor. All agreements of the Trustee in this Indenture shall bind
its successor.

     SECTION 12.12. MULTIPLE COUNTERPARTS.

     The parties may sign multiple counterparts of this Indenture. Each signed
counterpart shall be deemed an original, but all of them together represent the
same agreement.

     SECTION 12.13. SEPARABILITY.

     In case any provisions in this Indenture or in the Securities shall be
invalid, illegal or unenforceable, the validity, legality and enforceability of
the remaining provisions shall not in any way be affected or impaired thereby.

                                       56
<Page>

     SECTION 12.14. TABLE OF CONTENTS, HEADINGS, ETC.

     The table of contents, cross-reference sheet and headings of the Articles
and Sections of this Indenture have been inserted for convenience of reference
only, are not to be considered a part hereof, and shall in no way modify or
restrict any of the terms or provisions hereof.

                            [SIGNATURE PAGE FOLLOWS]

                                       57
<Page>

     IN WITNESS WHEREOF, the parties hereto have hereunto set their hands as of
the date and year first above written.

                                             INVITROGEN CORPORATION

                                             By:
                                                 -------------------------------
                                             Name:
                                             Title:

                                             STATE STREET BANK AND TRUST COMPANY
                                             OF CALIFORNIA, N.A., AS TRUSTEE

                                             By:
                                                 -------------------------------
                                             Name:
                                             Title:

<Page>

                                    EXHIBIT A
                           [FORM OF FACE OF SECURITY]

     [UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF
THE DEPOSITORY TRUST COMPANY TO THE COMPANY OR ITS AGENT FOR REGISTRATION OF
TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE ISSUED IS REGISTERED IN THE
NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (AND ANY PAYMENT HEREON IS MADE
TO CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY), ANY TRANSFER, PLEDGE OR OTHER
USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE
REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN. THIS SECURITY IS A
GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE HEREINAFTER REFERRED TO AND
IS REGISTERED IN THE NAME OF A DEPOSITARY OR A NOMINEE THEREOF. THIS SECURITY IS
EXCHANGEABLE FOR SECURITIES REGISTERED IN THE NAME OF A PERSON OTHER THAN THE
DEPOSITARY OR ITS NOMINEE ONLY IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE
INDENTURE AND, UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR
SECURITIES IN DEFINITIVE FORM, THIS SECURITY MAY NOT BE TRANSFERRED EXCEPT AS A
WHOLE BY THE DEPOSITARY TO A NOMINEE OF THE DEPOSITARY OR BY A NOMINEE OF THE
DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE DEPOSITARY OR BY THE
DEPOSITARY OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH
SUCCESSOR DEPOSITARY.](1)

     [THIS SECURITY (OR ITS PREDECESSOR) WAS ORIGINALLY ISSUED IN A TRANSACTION
EXEMPT FROM REGISTRATION UNDER THE UNITED STATES SECURITIES ACT OF 1933 (THE
"SECURITIES ACT"), AND THIS SECURITY AND THE SHARES OF COMMON STOCK ISSUABLE
UPON CONVERSION THEREOF MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED IN THE
ABSENCE OF SUCH REGISTRATION OR AN APPLICABLE EXEMPTION THEREFROM. EACH
PURCHASER OF THIS SECURITY IS HEREBY NOTIFIED THAT THE SELLER OF THIS SECURITY
MAY BE RELYING ON THE EXEMPTION FROM THE PROVISIONS OF SECTION 5 OF THE
SECURITIES ACT PROVIDED BY RULE 144A THEREUNDER.](2)

         THE HOLDER OF THIS SECURITY AGREES FOR THE BENEFIT OF THE COMPANY THAT
(A) THIS SECURITY AND THE SHARES OF COMMON STOCK ISSUABLE UPON CONVERSION
THEREOF MAY BE OFFERED, RESOLD, PLEDGED OR OTHERWISE TRANSFERRED, ONLY (I) IN
THE UNITED STATES TO A PERSON WHOM THE SELLER REASONABLY BELIEVES IS A QUALIFIED
INSTITUTIONAL BUYER (AS DEFINED IN RULE 144A UNDER THE SECURITIES ACT) IN A
TRANSACTION MEETING THE REQUIREMENTS OF RULE 144A, (II) OUTSIDE THE UNITED
STATES IN AN OFFSHORE TRANSACTION IN ACCORDANCE WITH RULE 904 UNDER THE
SECURITIES ACT, (III) PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE

----------

     (1)  These paragraphs should be included only if the Security is a Global
          Security.

     (2)  These paragraphs to be included only if the Security is a Transfer
          Restricted Security.

                                       A-1
<Page>

SECURITIES ACT PROVIDED BY RULE 144 THEREUNDER (IF AVAILABLE) OR (IV) PURSUANT
TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT, IN EACH OF
CASES (I) THROUGH (IV) IN ACCORDANCE WITH ANY APPLICABLE SECURITIES LAWS OF ANY
STATE OF THE UNITED STATES, AND (B) THE HOLDER WILL, AND EACH SUBSEQUENT HOLDER
IS REQUIRED TO, NOTIFY ANY PURCHASER OF THIS SECURITY FROM IT OF THE RESALE
RESTRICTIONS REFERRED TO IN (A) ABOVE.](2)

     [THE HOLDER OF THIS SECURITY IS ENTITLED TO THE BENEFITS OF A REGISTRATION
RIGHTS AGREEMENT (AS SUCH TERM IS DEFINED IN THE INDENTURE REFERRED TO ON THE
REVERSE HEREOF) AND, BY ITS ACCEPTANCE HEREOF, AGREES TO BE BOUND BY AND TO
COMPLY WITH THE PROVISIONS OF SUCH REGISTRATION RIGHTS AGREEMENT.](2)

----------

     (2)  These paragraphs to be included only if the Security is a Transfer
          Restricted Security.

                                       A-2
<Page>

                             INVITROGEN CORPORATION

CUSIP No.:  46185R AC4

                 2 1/4% CONVERTIBLE SUBORDINATED NOTES DUE 2006

               Invitrogen Corporation, a Delaware corporation (the "Company",
which term shall include any successor corporation under the Indenture referred
to on the reverse hereof), promises to pay to Cede & Co., or registered assigns,
the principal sum of Five Hundred Million Dollars ($500,000,000.00) on December
15, 2006, or such greater or lesser amount as is indicated on the Schedule of
Exchanges of Notes on the other side of this Note.

Interest Payment Dates:      June 15 and December 15, commencing June 15, 2002

Record Dates:                June 1 and December 1

               This Note is convertible as specified on the other side of this
Note. Additional provisions of this Note are set forth on the other side of this
Note.

                                SIGNATURE PAGE FOLLOWS

                                       A-3
<Page>

     IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed.

                                             INVITROGEN CORPORATION

                                             By:
                                                 -------------------------------
                                             Name:
                                             Title:

Attest:

--------------------------------------------
Name:
Title:

Dated:

TRUSTEE'S CERTIFICATE OF AUTHENTICATION
This is one of the Securities referred to in the within-mentioned Indenture.

STATE STREET BANK AND TRUST COMPANY OF CALIFORNIA, NATIONAL ASSOCIATION, as
Trustee

--------------------------------------------
Authorized Signatory

                                       A-4
<Page>

                       [FORM OF REVERSE SIDE OF SECURITY]

                             INVITROGEN CORPORATION
                 2 1/4% CONVERTIBLE SUBORDINATED NOTES DUE 2006

1.        INTEREST

     Invitrogen Corporation, a Delaware corporation (the "Company", which term
shall include any successor corporation under the Indenture hereinafter referred
to), promises to pay interest on the principal amount of this Note at the rate
of 2 1/4% per annum. The Company shall pay interest semiannually on June 15 and
December 15 of each year, commencing on June 15, 2002. Interest on the Notes
shall accrue from the most recent date to which interest has been paid or, if no
interest has been paid, from December 11, 2001; PROVIDED, HOWEVER, that if there
is not an existing default in the payment of interest and if this Note is
authenticated between a record date referred to on the face hereof and the next
succeeding interest payment date, interest shall accrue from such interest
payment date. Interest will be computed on the basis of a 360-day year of twelve
30-day months.

2.        REGISTRATION RIGHTS AGREEMENT

     The holder of this Note is entitled to the benefits of a Registration
Rights Agreement, dated as of December 11, 2001, among the Company and the
Initial Purchasers (the "Registration Rights Agreement"). Pursuant to the
Registration Rights Agreement the Company has agreed for the benefit of the
Holders of the Notes, that (i) it will, at its cost, within 90 days after the
closing of the sale of the Notes (the "Closing"), file a shelf registration
statement (the "Shelf Registration Statement") with the Securities and Exchange
Commission (the "Commission") with respect to resales of the Notes and the
Common Stock issuable upon conversion thereof, (ii) it will use its reasonable
best efforts to cause such Shelf Registration Statement to be declared effective
within 180 days after the Closing, and (iii) it will use its best efforts to
keep such Shelf Registration Statement continuously effective under the
Securities Act, subject to certain exceptions specified in the Registration
Rights Agreement until the second anniversary of the date of the Closing. As set
forth in the Registration Rights Agreement, the Company will be permitted to
suspend use of the prospectus that is part of the Shelf Registration Statement
during certain periods of time and in certain circumstances relating to pending
corporate developments and public filings with the SEC and similar events. If
(a) the Company fails to file the Shelf Registration Statement required by the
Registration Rights Agreement on or before the date specified above for such
filing, (b) such Shelf Registration Statement is not declared effective by the
Commission on or prior to the date specified above for such effectiveness, or
(c) the Shelf Registration Statement is declared effective but thereafter ceases
to be effective or useable in connection with resales of Transfer Restricted
Securities (as defined in the Registration Rights Agreement) during the periods
specified in the Registration Rights Agreement (each such event referred to in
clauses (a) through (c) above a "Registration Default"), then the Company will
pay Special Interest to each Holder of Transfer Restricted Securities, with
respect to the first 90-day period immediately following the occurrence of such
Registration Default in an amount equal to an increase in the annual interest
rate on the Notes of 0.25% ("Special Interest") and with respect to each
subsequent 90-day period, additional amounts equal to an increase in the annual
interest rate on the Notes of 0.25% until all Registration Defaults have been
cured, up to a maximum increase in the annual interest rate on the Notes equal
to 1.0%. All accrued Special Interest shall be paid by the Company on each
Interest Payment Date for which Special Interest is owed to the holders of
Global Notes by wire transfer of immediately available funds or by federal funds
check and to holders of certificated Notes registered as such as of the
preceding Record Date by mailing checks to their registered addresses. Following
the cure of all Registration Defaults, the application of Special Interest will
cease.

                                       B-5
<Page>

3.        METHOD OF PAYMENT

     The Company shall pay interest on this Note (except defaulted interest) to
the person who is the Holder of this Note at the close of business on June 1 or
December 1, as the case may be, next preceding the related interest payment
date. The Holder must surrender this Note to a Paying Agent to collect payment
of principal. The Company will pay principal and interest in money of the United
States that at the time of payment is legal tender for payment of public and
private debts. The Company may, however, pay principal and interest in respect
of any Certificated Security by check or wire payable in such money; PROVIDED,
HOWEVER, that a Holder with an aggregate principal amount in excess of
$2,000,000 will be paid by wire transfer in immediately available funds at the
election of such Holder if such Holder has provided wire transfer instructions
to the Company at least 10 Business Days prior to the payment date.

4.        PAYING AGENT, REGISTRAR AND CONVERSION AGENT

     Initially, State Street Bank and Trust Company of California, National
Association (the "Trustee", which term shall include any successor trustee under
the Indenture hereinafter referred to) will act as Paying Agent, Registrar and
Conversion Agent. The Company may change any Paying Agent, Registrar or
Conversion Agent without notice to the Holder. The Company or any of its
Subsidiaries may, subject to certain limitations set forth in the Indenture, act
as Paying Agent or Registrar.

5.        INDENTURE, LIMITATIONS

     This Note is one of a duly authorized issue of Securities of the Company
designated as its 2 1/4% Convertible Subordinated Notes due 2006 (the "Notes"),
issued under an Indenture dated as of December 11, 2001 (together with any
supplemental indentures thereto, the "Indenture"), between the Company and the
Trustee. The terms of this Note include those stated in the Indenture and those
required by or made part of the Indenture by reference to the Trust Indenture
Act of 1939, as amended, as in effect on the date of the Indenture. This Note is
subject to all such terms, and the Holder of this Note is referred to the
Indenture and said Act for a statement of them. The Notes are subordinated
unsecured obligations of the Company limited to $600,000,000 aggregate principal
amount. The Indenture does not limit other debt of the Company, secured or
unsecured, including Senior Indebtedness.

6.        OPTIONAL REDEMPTION

     The Notes are subject to redemption, at any time on or after December 20,
2005, as a whole or from time to time in part, at the election of the Company.
The Redemption Price is 100% of the principal amount together with accrued
interest up to but not including the Redemption Date; PROVIDED THAT if the
Redemption Date falls after an interest payment record date and on or before an
interest payment date, then the interest will be payable to the Holders in whose
names the Notes are registered at the close of business on the relevant interest
payment record date.

     No sinking fund is provided for the Notes.

7.        NOTICE OF REDEMPTION

     Notice of redemption will be mailed by first-class mail at least 20 days
but not more than 60 days before the Redemption Date to each Holder of Notes to
be redeemed at its registered address. Notes in denominations larger than $1,000
may be redeemed in part, but only in whole multiples of $1,000. On and after the
Redemption Date, subject to the deposit with the Paying Agent of funds
sufficient to pay the

                                       B-6
<Page>

Redemption Price plus accrued interest, if any, accrued to, but excluding, the
Redemption Date, interest shall cease to accrue on Notes or portions of them
called for redemption.

8.        PURCHASE OF NOTES AT OPTION OF HOLDER UPON A CHANGE IN CONTROL

     At the option of the Holder and subject to the terms and conditions of the
Indenture, the Company shall become obligated to purchase all or any part
specified by the Holder (so long as the principal amount of such part is $1,000
or an integral multiple of $1,000 in excess thereof) of the Notes held by such
Holder at a purchase price equal to 100% of the principal amount thereof
together with accrued interest up to, but excluding, the Change in Control
Purchase Date. The Holder shall have the right to withdraw any Change in Control
Purchase Notice (in whole or in a portion thereof that is $1,000 or an integral
multiple of $1,000 in excess thereof) at any time prior to the close of business
on the second Business Day next preceding the Change in Control Purchase Date by
delivering a written notice of withdrawal to the Company, Depositary or Paying
Agent in accordance with the terms of the Indenture.

9.        CONVERSION

     A Holder of a Note may convert the principal amount of such Note (or any
portion thereof equal to $1,000 or any integral multiple of $1,000 in excess
thereof) into Common Stock at any time prior to the close of business on the
Final Maturity Date, at the Conversion Price then in effect; PROVIDED, HOWEVER,
that, if such Note is called for redemption or submitted or presented for
purchase pursuant to Article 3 of the Indenture, such conversion right shall
terminate at the close of business on the Business Day immediately preceding the
Redemption Date or Change in Control Purchase Date, as the case may be, for such
Note or such earlier date as the Holder presents such Security for redemption or
for purchase (unless the Company shall default in making the redemption payment
or Change in Control Purchase Price payment when due, in which case the
conversion right shall terminate at the close of business on the date such
default is cured and such Note is redeemed or purchased, as the case may be).

     The initial Conversion Price is $86.10 per share, subject to adjustment
under certain circumstances as provided in the Indenture. The number of shares
of Common Stock issuable upon conversion of a Note is determined by dividing the
principal amount of the Note or portion thereof converted by the Conversion
Price in effect on the Conversion Date. No fractional shares will be issued upon
conversion; in lieu thereof, an amount will be paid in cash based upon the
Closing Price (as defined in the Indenture) of the Common Stock on the Trading
Day immediately prior to the Conversion Date.

     To convert a Note, a Holder must (a) complete and manually sign the
conversion notice set forth below and deliver such notice to a Conversion Agent,
(b) surrender the Note to a Conversion Agent, (c) furnish appropriate
endorsements and transfer documents if required by a Registrar or a Conversion
Agent, and (d) pay any transfer or similar tax, if required. Notes so
surrendered for conversion (in whole or in part) during the period from the
close of business on any regular record date to the opening of business on the
next succeeding interest payment date (excluding Notes or portions thereof
called for redemption or subject to purchase upon a Change in Control on a
Redemption Date or Change in Control Purchase Date, as the case may be, during
the period beginning at the close of business on a regular record date and
ending at the opening of business on the first Business Day after the next
succeeding interest payment date, or if such interest payment date is not a
Business Day, the second such Business Day) shall also be accompanied by payment
in funds acceptable to the Company of an amount equal to the interest payable on
such interest payment date on the principal amount of such Note then being
converted, and such interest shall be payable to such registered Holder
notwithstanding the conversion of such Note, subject to the provisions of this

                                       B-7
<Page>

Indenture relating to the payment of defaulted interest by the Company. If the
Company defaults in the payment of interest payable on such interest payment
date, the Company shall promptly repay such funds to such Holder. A Holder may
convert a portion of a Note equal to $1,000 or any integral multiple thereof.

     A Note in respect of which a Holder had delivered a Change in Control
Purchase Notice exercising the option of such Holder to require the Company to
purchase such Note may be converted only if the Change in Control Purchase
Notice is withdrawn in accordance with the terms of the Indenture.

10.       CONVERSION ARRANGEMENT ON CALL FOR REDEMPTION

     Any Notes called for redemption, unless surrendered for conversion before
the close of business on the Business Day immediately preceding the Redemption
Date, may be deemed to be purchased from the Holders of such Notes at an amount
not less than the Redemption Price, together with accrued interest, if any, to,
but not including, the Redemption Date, by one or more investment bankers or
other purchasers who may agree with the Company to purchase such Notes from the
Holders, to convert them into Common Stock of the Company and to make payment
for such Notes to the Paying Agent in trust for such Holders.

11.       SUBORDINATION

     The indebtedness evidenced by the Notes is, to the extent and in the manner
provided in the Indenture, subordinate and junior in right of payment to the
prior payment in full of all Senior Indebtedness of the Company. Any Holder by
accepting this Note agrees to and shall be bound by such subordination
provisions and authorizes the Trustee to give them effect. In addition to all
other rights of Senior Indebtedness described in the Indenture, the Senior
Indebtedness shall continue to be Senior Indebtedness and entitled to the
benefits of the subordination provisions irrespective of any amendment,
modification or waiver of any terms of any instrument relating to the Senior
Indebtedness or any extension or renewal of the Senior Indebtedness.

12.       DENOMINATIONS, TRANSFER, EXCHANGE

     The Notes are in registered form, without coupons, in denominations of
$1,000 and integral multiples of $1,000. A Holder may register the transfer of
or exchange Notes in accordance with the Indenture. The Registrar may require a
Holder, among other things, to furnish appropriate endorsements and transfer
documents and to pay any taxes or other governmental charges that may be imposed
in relation thereto by law or permitted by the Indenture.

13.       PERSONS DEEMED OWNERS

     The Holder of a Note may be treated as the owner of it for all purposes.

14.       UNCLAIMED MONEY

     If money for the payment of principal or interest remains unclaimed for two
years, the Trustee or Paying Agent will pay the money back to the Company at its
written request, subject to applicable unclaimed property law. After that,
Holders entitled to money must look to the Company for payment as general
creditors unless an applicable abandoned property law designates another person.

                                       B-8
<Page>

15.       AMENDMENT, SUPPLEMENT AND WAIVER

     Subject to certain exceptions, the Indenture or the Notes may be amended or
supplemented with the consent of the Holders of at least a majority in aggregate
principal amount of the Notes then outstanding, and an existing default or Event
of Default and its consequence or compliance with any provision of the Indenture
or the Notes may be waived in a particular instance with the consent of the
Holders of a majority in aggregate principal amount of the Notes then
outstanding. Without the consent of or notice to any Holder, the Company and the
Trustee may amend or supplement the Indenture or the Notes to, among other
things, cure any ambiguity, defect or inconsistency or make any other change
that does not adversely affect the rights of any Holder.

16.       SUCCESSOR ENTITY

     When a successor corporation assumes all the obligations of its predecessor
under the Notes and the Indenture in accordance with the terms and conditions of
the Indenture, the predecessor corporation (except in certain circumstances
specified in the Indenture) shall be released from those obligations.

17.       DEFAULTS AND REMEDIES

     Under the Indenture, an Event of Default includes: (i) default for 30 days
in payment of any interest or Special Interest on any Notes; (ii) default in
payment of any principal (including, without limitation, any premium, if any) on
the Notes when due; (iii) failure by the Company for 60 days after notice to it
to comply with any of its other agreements contained in the Indenture or the
Notes; (iv) default in the payment of certain indebtedness of the Company or a
Significant Subsidiary; (v) the Company fails to provide a Purchase Offer within
30 days after notice of failure to timely deliver the same; and (vi) certain
events of bankruptcy, insolvency or reorganization of the Company or any
Significant Subsidiary. If an Event of Default (other than as a result of
certain events of bankruptcy, insolvency or reorganization of the Company)
occurs and is continuing, the Trustee or the Holders of at least 25% in
aggregate principal amount of the Notes then outstanding may declare all unpaid
principal to the date of acceleration on the Notes then outstanding to be due
and payable immediately, all as and to the extent provided in the Indenture. If
an Event of Default occurs as a result of certain events of bankruptcy,
insolvency or reorganization of the Company, unpaid principal of the Notes then
outstanding shall become due and payable immediately without any declaration or
other act on the part of the Trustee or any Holder, all as and to the extent
provided in the Indenture. Holders may not enforce the Indenture or the Notes
except as provided in the Indenture. The Trustee may require indemnity
satisfactory to it before it enforces the Indenture or the Notes. Subject to
certain limitations, Holders of a majority in aggregate principal amount of the
Notes then outstanding may direct the Trustee in its exercise of any trust or
power. The Trustee may withhold from Holders notice of any continuing default
(except a default in payment of principal or interest) if it determines that
withholding notice is in their interests. The Company is required to file
periodic reports with the Trustee as to the absence of default.

18.       TRUSTEE DEALINGS WITH THE COMPANY

     State Street Bank and Trust Company of California, National Association,
the Trustee under the Indenture, in its individual or any other capacity, may
make loans to, accept deposits from and perform services for the Company or an
Affiliate of the Company, and may otherwise deal with the Company or an
Affiliate of the Company, as if it were not the Trustee.

                                       B-9
<Page>

19.       NO RECOURSE AGAINST OTHERS

     A director, officer, employee or shareholder, as such, of the Company shall
not have any liability for any obligations of the Company under the Notes or the
Indenture nor for any claim based on, in respect of or by reason of such
obligations or their creation. The Holder of this Note by accepting this Note
waives and releases all such liability. The waiver and release are part of the
consideration for the issuance of this Note.

20.       AUTHENTICATION

     This Note shall not be valid until the Trustee or an authenticating agent
manually signs the certificate of authentication on the other side of this Note.

21.       ABBREVIATIONS AND DEFINITIONS

     Customary abbreviations may be used in the name of the Holder or an
assignee, such as: TEN COM (= tenants in common), TEN ENT (= tenants by the
entireties), JT TEN (= joint tenants with right of survivorship and not as
tenants in common), CUST (= Custodian) and UGMA (= Uniform Gifts to Minors Act).

     All terms defined in the Indenture and used in this Note but not
specifically defined herein are defined in the Indenture and are used herein as
so defined.

22.       INDENTURE TO CONTROL; GOVERNING LAW

     In the case of any conflict between the provisions of this Note and the
Indenture, the provisions of the Indenture shall control. This Note shall be
governed by, and construed in accordance with, the laws of the State of New
York, without regard to principals of conflicts of law.

     The Company will furnish to any Holder, upon written request and without
charge, a copy of the Indenture. Requests may be made to: Invitrogen
Corporation, 1600 Faraday Avenue, Carlsbad, California 92008, Attention:
Investor Relations.

                                      B-10
<Page>

                                 ASSIGNMENT FORM

     To assign this Note, fill in the form below:

     I or we assign and transfer this Note to

--------------------------------------------------------------------------------
                  (Insert assignee's soc. sec. or tax I.D. no.)

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
              (Print or type assignee's name, address and zip code)

and irrevocably appoint

--------------------------------------------------------------------------------

agent to transfer this Note on the books of the Company. The agent may
substitute another to act for him or her.

                                             Your Signature:

Date:
      --------------------------------       -----------------------------------
                                             (Sign exactly as your name appears
                                             on the other side of this Note)

*Signature guaranteed by:

By:
    -----------------------------------------------

          *    The signature must be guaranteed by an institution which is a
               member of one of the following recognized signature guaranty
               programs: (i) the Securities Transfer Agent Medallion Program
               (STAMP); (ii) the New York Stock Exchange Medallion Program
               (MSP); (iii) the Stock Exchange Medallion Program (SEMP); or (iv)
               such other guaranty program acceptable to the Trustee.

                                      B-11
<Page>

                                CONVERSION NOTICE

     To convert this Note into Common Stock of the Company, check the box: / /

     To convert only part of this Note, state the principal amount to be
converted (must be $1,000 or a integral multiple of $1,000): $             .
                                                              -------------

     If you want the stock certificate made out in another person's name, fill
in the form below:

--------------------------------------------------------------------------------
                  (Insert assignee's soc. sec. or tax I.D. no.)

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------

--------------------------------------------------------------------------------
              (Print or type assignee's name, address and zip code)

                                             Your Signature:

Date:
      --------------------------------       -----------------------------------
                                             (Sign exactly as your name appears
                                             on the other side of this Note)

*Signature guaranteed by:

By:
    -----------------------------------------------

          *    The signature must be guaranteed by an institution which is a
               member of one of the following recognized signature guaranty
               programs: (i) the Securities Transfer Agent Medallion Program
               (STAMP); (ii) the New York Stock Exchange Medallion Program
               (MSP); (iii) the Stock Exchange Medallion Program (SEMP); or (iv)
               such other guaranty program acceptable to the Trustee.

                                      B-12
<Page>

                           OPTION TO ELECT REPURCHASE
                            UPON A CHANGE OF CONTROL

To:  Invitrogen Corporation

     The undersigned registered owner of this Security hereby irrevocably
acknowledges receipt of a notice from Invitrogen Corporation (the "Company") as
to the occurrence of a Change in Control with respect to the Company and
requests and instructs the Company to redeem the entire principal amount of this
Security, or the portion thereof (which is $1,000 or an integral multiple
thereof) below designated, in accordance with the terms of the Indenture
referred to in this Security at the Change in Control Purchase Price, together
with accrued interest to, but excluding, such date, to the registered Holder
hereof.

Dated:
      ------------                           -----------------------------------

                                             -----------------------------------
                                             Signature(s)

                                             Signature(s) must be guaranteed by
                                             a qualified guarantor institution
                                             with membership in an approved
                                             signature guarantee program
                                             pursuant to Rule 17Ad-15 under the
                                             Securities Exchange Act of 1934.

                                             -----------------------------------
                                             Signature Guaranty

Principal amount to be redeemed
(in an integral multiple of $1,000, if less than all):

-----------------------------------

NOTICE: The signature to the foregoing Election must correspond to the Name as
written upon the face of this Security in every particular, without alteration
or any change whatsoever.

                                      B-13
<Page>

                         SCHEDULE OF EXCHANGES OF NOTES(4)

     The following exchanges, redemptions, repurchases or conversions of a part
of this global Note have been made:

<Table>
<Caption>
       PRINCIPAL AMOUNT
     OF THIS GLOBAL NOTE                 AUTHORIZED                                                AMOUNT OF
        FOLLOWING SUCH                  SIGNATORY OF            AMOUNT OF DECREASE IN             INCREASE IN
        DECREASE DATE                    SECURITIES               PRINCIPAL AMOUNT              PRINCIPAL AMOUNT
  OF EXCHANGE (OR INCREASE)               CUSTODIAN              OF THIS GLOBAL NOTE          OF THIS GLOBAL NOTE
-----------------------------         ----------------        -------------------------      -----------------------
<S>                                   <C>                     <C>                            <C>

</Table>

----------
     (4)  This schedule should be included only if the Security is a Global
          Security.

                                      B-14
<Page>

                                    EXHIBIT B

            CERTIFICATE TO BE DELIVERED UPON EXCHANGE OR REGISTRATION
                 OF TRANSFER OF TRANSFER RESTRICTED SECURITIES(5)

Re:  2 1/4% Convertible Subordinated Notes due 2006 (the "Notes") of Invitrogen
Corporation

     This certificate relates to $_______ principal amount of Notes owned in
(check applicable box)

     / / book-entry or / / definitive form by ___________________ (the
"Transferor").

     The Transferor has requested a Registrar or the Trustee to exchange or
register the transfer of such Notes.

     In connection with such request and in respect of each such Note, the
Transferor does hereby certify that the Transferor is familiar with transfer
restrictions relating to the Notes as provided in Section 2.12 of the Indenture
dated as of December 11, 2001 between Invitrogen Corporation and State Street
Bank and Trust Company of California, N.A., as trustee (the "Indenture"), and
the transfer of such Note is being made pursuant to an effective registration
statement under the Securities Act of 1933, as amended (the "Securities Act")
(check applicable box) or the transfer or exchange, as the case may be, of such
Note does not require registration under the Securities Act because (check
applicable box):

     / /  Such Note is being transferred pursuant to an effective registration
          statement under the Securities Act.

     / /  Such Note is being acquired for the Transferor's own account,
          without transfer.

     / /  Such Note is being transferred to the Company or a Subsidiary (as
          defined in the Indenture) of the Company.

     / /  Such Note is being transferred to a person the Transferor reasonably
          believes is a "qualified institutional buyer" (as defined in Rule 144A
          or any successor provision thereto ("Rule 144A") under the Securities
          Act) that is purchasing for its own account or for the account of a
          "qualified institutional buyer", in each case to whom notice has been
          given that the transfer is being made in reliance on such Rule 144A,
          and in each case in reliance on Rule 144A.

     / /  Such Note is being transferred pursuant to and in compliance with an
          exemption from the registration requirements under the Securities Act
          in accordance with Rule 144 (or any successor thereto) ("Rule 144")
          under the Securities Act.

     Such Note is being transferred pursuant to and in compliance with an
exemption from the registration requirements of the Securities Act (other than
an exemption referred to above) and as a result of which such

----------
     (5)  This certificate should only be included if this Security is a
Transfer Restricted Security.

                                       B-1
<Page>

Note will, upon such transfer, cease to be a "restricted security" within the
meaning of Rule 144 under the Securities Act.

     The Transferor acknowledges and agrees that, if the transferee will hold
any such Notes in the form of beneficial interests in a global Note which is a
"restricted security" within the meaning of Rule 144 under the Securities Act,
then such transfer can only be made pursuant to Rule 144A under the Securities
Act and such transferee must be a "qualified institutional buyer" (as defined in
Rule 144A).

Date:
      -----------------------------------    -----------------------------------
                                             (Insert Name of Transferor)

                                       B-2

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