Document:

<PAGE>

       UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE
OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), NEW YORK,
NEW YORK, 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 SUCH OTHER NAME AS IS REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC
(AND ANY PAYMENT IS MADE TO CEDE & CO., OR TO SUCH OTHER ENTITY AS IS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC) ANY TRANSFER, PLEDGE OR
OTHER USE HEREOF FOR VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL
INASMUCH AS THE REGISTERED OWNER HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

       TRANSFERS OF THIS GLOBAL NOTE SHALL BE LIMITED TO TRANSFERS IN WHOLE,
BUT NOT IN PART, TO NOMINEES OF DTC OR TO A SUCCESSOR THEREOF OR SUCH
SUCCESSOR'S NOMINEE AND TRANSFERS OF PORTIONS OF THIS GLOBAL NOTE SHALL BE
LIMITED TO TRANSFERS MADE IN ACCORDANCE WITH THE RESTRICTIONS SET FORTH IN
THE INDENTURE REFERRED TO ON THE REVERSE HEREOF.

       THE SECURITY (OR ITS PREDECESSOR) EVIDENCED HEREBY WAS ORIGINALLY
ISSUED IN A TRANSACTION EXEMPT FROM REGISTRATION UNDER SECTION 5 OF THE
UNITED STATES SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND
THE SECURITY EVIDENCED HEREBY AND ANY SHARES OF COMMON STOCK ISSUED UPON
CONVERSION HEREOF MAY NOT BE OFFERED, SOLD OR OTHERWISE TRANSFERRED IN THE
ABSENCE OF SUCH REGISTRATION OR AN APPLICABLE EXEMPTION THEREFROM. EACH
PURCHASER OF THE SECURITY EVIDENCED HEREBY IS HEREBY NOTIFIED THAT THE SELLER
MAY BE RELYING ON THE EXEMPTION FROM THE PROVISIONS OF SECTION 5 OF THE
SECURITIES ACT PROVIDED BY RULE 144A THEREUNDER. THE HOLDER OF THE SECURITY
EVIDENCED HEREBY AGREES FOR THE BENEFIT OF THE COMPANY THAT (A) SUCH SECURITY
AND ANY SHARES OF COMMON STOCK ISSUED UPON CONVERSION HEREOF MAY BE RESOLD,
PLEDGED OR OTHERWISE TRANSFERRED, ONLY (1) (a) TO A PERSON WHO 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, (b) IN A TRANSACTION MEETING THE REQUIREMENTS OF RULE 144 UNDER
THE SECURITIES ACT, IF AVAILABLE, (c) OUTSIDE THE UNITED STATES TO A NON-U.S.
PERSON IN A TRANSACTION MEETING THE REQUIREMENTS OF RULE 904 UNDER THE
SECURITIES ACT OR (d) IN ACCORDANCE WITH ANOTHER EXEMPTION FROM THE
REGISTRATION REQUIREMENTS OF THE SECURITIES ACT (AND BASED UPON AN OPINION OF
COUNSEL IF THE COMPANY SO REQUESTS), (2) TO THE COMPANY OR (3) PURSUANT TO AN
EFFECTIVE REGISTRATION STATEMENT AND, IN EACH CASE, IN ACCORDANCE WITH ANY
APPLICABLE SECURITIES LAWS OF ANY STATE OF THE UNITED STATES OR ANY OTHER
APPLICABLE JURISDICTION AND (B) THE PURCHASER WILL, AND EACH SUBSEQUENT
PURCHASER IS REQUIRED TO, NOTIFY ANY SUBSEQUENT PURCHASER FROM IT OF THE
SECURITY EVIDENCED HEREBY OR ANY COMMON STOCK ISSUABLE UPON CONVERSION HEREOF
OF THE RESALE RESTRICTIONS SET FORTH IN (A) ABOVE.

<PAGE>

No. 1
                                                                   $172,500,000

CUSIP No. 461 85R AA8

                    5 1/2% CONVERTIBLE SUBORDINATED NOTE DUE 2007

          Invitrogen Corporation, a Delaware corporation (the "COMPANY"),
promises to pay to Cede & Co., or registered assigns, the principal sum of One
Hundred Seventy-Two Million Five Hundred Thousand Dollars ($172,500,000.00), or
such other amount as is indicated on Schedule A hereof, on March 1, 2007,
subject to the further provisions of this Note set forth on the reverse hereof
which further provisions shall for all purposes have the same effect as if set
forth at this place.

Interest Payment Dates:  March 1 and September 1, commencing September 1, 2000

Record Dates:            February 15 and August 15

          IN WITNESS WHEREOF, Invitrogen Corporation has caused this Note to be
signed manually or by facsimile by one of its duly authorized officers.

                                   Dated: March 1, 2000

                                   INVITROGEN CORPORATION

                                   By:  /s/ James R. Glynn
                                      ---------------------------------------
                                       Title: Executive Vice President & CFO

TRUSTEE'S CERTIFICATE OF AUTHENTICATION
This is one of the 5 1/2% Convertible Subordinated
Notes due 2007 described in the
within-mentioned Indenture.

State Street Bank and Trust Company of California, N.A., as Trustee

By:       /s/ Mark Henson
   ----------------------------
          Authorized Officer

<PAGE>

                               INVITROGEN CORPORATION

                    5 1/2% Convertible Subordinated Note due 2007

          1.   INTEREST.  INVITROGEN CORPORATION, a Delaware corporation (the
"COMPANY"), is the issuer of 5 1/2% Convertible Subordinated Notes due 2007
(the "NOTES").  The Notes will accrue interest at a rate of 5 1/2% per annum.
 The Company promises to pay interest on the Notes in cash semiannually on
each March 1 and September 1, commencing on September 1, 2000, to Holders of
record on the immediately preceding February 15 and August 15, respectively.
Interest on the Notes will accrue from the most recent date to which interest
has been paid, or if no interest has been paid, from March 1, 2000.  Interest
will be computed on the basis of a 360-day year of twelve 30-day months.  The
Company will pay interest on overdue principal at the interest rate borne by
the Notes, compounded semiannually, and it shall pay interest on overdue
installments of interest (without regard to any applicable grace period) at
the same interest rate compounded semiannually.

          2.   REGISTRATION RIGHTS.  The holder of this Note is entitled to the
benefits of a Registration Rights Agreement, dated as of March 1, 2000, 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 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

                                        3
<PAGE>

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.

          3.   PAYMENTS.  All payments made by the Company on this Note shall
be made without deduction or withholding for or on account of, any and all
present or future taxes, duties, assessments, or governmental charges of
whatever nature unless the deduction or withholding of such taxes, duties,
assessments or governmental charges is then required by law.

          4.   METHOD OF PAYMENT.  The Company will pay interest on the Notes
(except defaulted interest) to the Persons who are registered Holders of
Notes at the close of business on the record date for the next interest
payment date even though Notes are canceled after the record date and on or
before the interest payment date.  Holders must surrender Notes to a Paying
Agent to collect principal and premium payments.  The Company will pay
principal, premium, if any, interest and Special Interest, if any, in money
of the United States that at the time of payment is legal tender for payment
of public and private debts.  However, the Company may pay principal,
premium, if any, interest and Special Interest, if any, by check payable in
such money.  It may mail an interest or Special Interest check to a Holder's
registered address.  If a Holder so requests, principal, premium, if any,
interest and Special Interest, if any, shall be paid by wire transfer of
immediately available funds to an account previously specified in writing by
such Holder to the Company and the Trustee.

          5.   PAYING AGENT, CONVERSION AGENT AND REGISTRAR.  The Trustee
will act as Paying Agent, Conversion Agent and Registrar in the City of New
York, New York.  The Company may change any Paying Agent, Conversion Agent or
Registrar without prior notice.  The Company or any of its Affiliates may act
in any such capacity.

          6.   INDENTURE.  The Company issued the Notes under an Indenture,
dated as of March 1, 2000 (the "INDENTURE"), between the Company and State
Street Bank and Trust Company of California, N.A., as Trustee.  The terms of
the Notes include those stated in the Indenture and those made part of the
Indenture by the Trust Indenture Act of 1939 (15 U.S. Code Sections
77aaa-77bbbb) (the "TIA") as in effect on the date of the Indenture.  The
Notes are subject to, and qualified by, all such terms, certain of which are
summarized hereon, and Holders are referred to the Indenture and such Act for
a statement of such terms.  The Notes are unsecured general obligations of
the Company limited to $172,500,000 in aggregate principal amount and
subordinated in right of payment to all existing and future Senior Debt of
the Company.

          7.   OPTIONAL REDEMPTION.  At any time on or after March 1, 2003
the Company may redeem any portion of the Notes, in whole or in part, upon
not less than 30 nor more than 60 days' notice, at the redemption prices
(expressed as percentages of principal amount thereof), together with accrued
and unpaid interest thereon to, but excluding, the applicable redemption
date.  If redeemed during the period beginning March 1, 2003 and ending on
February 29, 2004, the redemption price shall be 103.143%, and if redeemed
during the 12-month period commencing on March 1:

                                        4
<PAGE>

<TABLE>
<CAPTION>
               Year                          Redemption Price
               ----                          ----------------
               <S>                           <C>
               2004......................       102.357%
               2005......................       101.571%
               2006......................       100.786%
               2007......................       100.000%
</TABLE>

     In the event the Company redeems less than all of the outstanding Notes,
the Notes to be redeemed shall be selected by the Trustee in accordance with
Section 3.02 of the Indenture.  In the event a portion of an outstanding Note is
selected for redemption and such Note is converted in part after such selection,
the converted portion of such Note shall be deemed (so far as may be) to be the
portion to be selected for redemption in accordance with Section 3.02 of the
Indenture.  The Company may not give notice of any redemption if the Company has
defaulted in payment of interest and the default is continuing.

          8.   NOTICE OF REDEMPTION.  Notice of redemption will be mailed at
least 30 days but not more than 60 days before the redemption date to each
Holder of the Notes to be redeemed at his address of record.  The Notes in
denominations larger than $1,000 may be redeemed in part but only in integral
multiples of $1,000.  In the event of a redemption of less than all of the
Notes, the Notes will be chosen for redemption by the Trustee in accordance with
the Indenture.  On and after the redemption date, interest ceases to accrue on
the Notes or portions of them called for redemption.

          If this Note is redeemed subsequent to a record date with respect to
any interest payment date specified above and on or prior to such interest
payment date, then any accrued interest will be paid to the Person in whose name
this Note is registered at the close of business on such record date.

          9.   MANDATORY REDEMPTION.  The Company will not be required to make
mandatory redemption or repurchase payments with respect to the Notes.  There
are no sinking fund payments with respect to the Notes.

          10.  REPURCHASE AT OPTION OF HOLDER.  If there is a Change of Control,
the Company shall be required to offer to purchase on the Purchase Date all
outstanding Notes at a purchase price equal to 100% of the aggregate principal
amount thereof, plus accrued and unpaid interest, if any, to the Purchase Date.
Holders of Notes that are subject to an offer to purchase will receive a Change
of Control Offer from the Company in accordance with Section 3.09 of the
Indenture and may elect to have such Notes or portions thereof in authorized
denominations purchased by completing the form entitled "Option of Holder to
Elect Purchase" appearing below.

          11.  SUBORDINATION.  The payment of the principal of, interest on or
any other amounts due on the Notes is subordinated in right of payment to all
existing and future Senior Debt of the Company, as described in the Indenture.
Each Holder, by accepting a Note, agrees to such subordination and authorizes
and directs the Trustee on its behalf to take such action as may be necessary or
appropriate to effectuate the subordination so provided and appoints the Trustee
as its attorney-in-fact for such purpose.

                                        5
<PAGE>

          12.  CONVERSION.  The holder of any Note has the right, exercisable
at any time following the Issuance Date and prior to the close of business
(New York time) on the date of the Note's maturity, to convert the principal
amount thereof (or any portion thereof that is an integral multiple of
$1,000) into shares of Common Stock at the initial Conversion Price of $85.20
per share, subject to adjustment under certain circumstances as set forth in
the Indenture, except that if a Note is called for redemption, the conversion
right will terminate at the close of business on the Business Day immediately
preceding the date fixed for redemption.

          To convert a Note, a holder must (1) complete and sign a conversion
notice substantially in the form set forth below, (2) surrender the Note to a
Conversion Agent, (3) furnish appropriate endorsements or transfer documents
if required by the Registrar or Conversion Agent and (4) pay any transfer or
similar tax, if required.  No payment or adjustment will be made for accrued
and unpaid interest on a converted Note, but if any holder surrenders a Note
for conversion after the close of business on the record date for the payment
of an installment of interest and prior to the opening of business on the
next interest payment date, then, notwithstanding such conversion, the
interest payable on such interest payment date shall be paid to the holder of
such Note on such record date.  Any Notes that are, however, delivered to the
Company for conversion after any record date but before the next interest
payment date must, except as described in the next sentence, be accompanied
by a payment equal to the interest payable on such interest payment date on
the principal amount of convertible notes being converted.  The payment to
the Company described in the preceding sentence shall not be required if,
during that period between a record date and the next interest payment date,
a conversion occurs on or after the date that the Company has issued a
redemption notice and prior to the date of redemption stated in such notice.
If any Notes are converted after an interest payment date but on or before
the next record date, no interest will be paid on those Notes.  The number of
shares issuable upon conversion of a Note is determined by dividing the
principal amount of the Note converted by the Conversion Price in effect on
the Conversion Date.  No fractional shares will be issued upon conversion but
a cash adjustment will be made for any fractional interest.

          A Note in respect of which a holder has delivered an "Option of
Holder to Elect Purchase" form appearing below exercising the option of such
holder to require the Company to purchase such Note may be converted only if
the notice of exercise is withdrawn as provided above and in accordance with
the terms of the Indenture.  The above description of conversion of the Notes
is qualified by reference to, and is subject in its entirety by, the more
complete description thereof contained in the Indenture.

          13.  DENOMINATIONS, TRANSFER, EXCHANGE.  The Notes are in
registered form, without coupons, in denominations of $1,000 and integral
multiples of $1,000.  The transfer of Notes may be registered, and Notes may
be exchanged, as provided in the Indenture.  The Registrar may require a
Holder, among other things, to furnish appropriate endorsements and transfer
documents and to pay any taxes and fees required by law or permitted by the
Indenture.  The Registrar need not exchange or register the transfer of any
Note or portion of a Note selected for redemption (except the unredeemed
portion of any Note being redeemed in part).  Also, it need not exchange or
register the transfer of any Note for a period of 15 days before a selection
of Notes to be redeemed.

                                        6
<PAGE>

          14.  PERSONS DEEMED OWNERS.  Except as provided in Section 4 of
this Note, the registered Holder of a Note may be treated as its owner for
all purposes.

          15.  UNCLAIMED MONEY.  If money for the payment of principal or
interest remains unclaimed for two years, the Trustee and the Paying Agent
shall pay the money back to the Company at its written request.  After that,
Holders of Notes entitled to the money must look to the Company for payment
unless an abandoned property law designates another Person and all liability
of the Trustee and such Paying Agent with respect to such money shall cease.

          16.  DEFAULTS AND REMEDIES.  The Notes shall have the Events of
Default set forth in Section 8.01 of the Indenture.  Subject to certain
limitations in the Indenture, if an Event of Default occurs and is
continuing, the Trustee by notice to the Company or the Holders of at least
25% in aggregate principal amount of the then outstanding Notes by notice to
the Company and the Trustee may declare all the Notes to be due and payable
immediately, except that in the case of an Event of Default arising from
certain events of bankruptcy, insolvency or reorganization, all unpaid
principal and interest accrued on the Notes shall become due and payable
immediately without further action or notice. The Holders of a majority in
principal amount of the Notes then outstanding by written notice to the
Trustee may rescind an acceleration and its consequences if the rescission
would not conflict with any judgment or decree and if all existing Events of
Default have been cured or waived except nonpayment of principal or interest
that has become due solely because of the acceleration. Holders may not
enforce the Indenture or the Notes except as provided in the Indenture.
Subject to certain limitations, Holders of a majority in principal amount of
the then outstanding Notes issued under the Indenture may direct the Trustee
in its exercise of any trust or power.  The Company must furnish annually
compliance certificates to the Trustee.  The above description of Events of
Default and remedies is qualified by reference, and subject in its entirety,
to the more complete description thereof contained in the Indenture.

          17.  AMENDMENTS, SUPPLEMENTS AND WAIVERS.  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 principal amount of the
then outstanding Notes (including consents obtained in connection with a
tender offer or exchange offer for Notes), and any existing default may be
waived with the consent of the Holders of a majority in principal amount of
the then outstanding Notes.  Without the consent of any Holder, the Indenture
or the Notes may be amended among other things, to cure any ambiguity, defect
or inconsistency, to provide for uncertificated Notes in addition to or in
place of certificated Notes, to provide for assumption of the Company's
obligations to Holders, to make any change that does not adversely affect the
rights of any Holder or to qualify the Indenture under the TIA or to comply
with the requirements of the SEC in order to maintain the qualification of
the Indenture under the TIA.

          18.  TRUSTEE DEALINGS WITH THE COMPANY.  The Trustee, in its
individual or any other capacity may become the owner or pledgee of the Notes
and may otherwise deal with the Company or an Affiliate with the same rights
it would have, as if it were not Trustee, subject to certain limitations
provided for in the Indenture and in the TIA.  Any Agent may do the same with
like rights.

                                        7
<PAGE>

          19.  NO RECOURSE AGAINST OTHERS.  A director, officer, employee,
incorporator or shareholder of the Company, as such, shall not have any
liability for any obligations of the Company under the Notes or the Indenture
or for any claim based on, in respect of or by reason of such obligations or
their creation.  Each Holder of the Notes by accepting a Note waives and
releases all such liability.  The waiver and release are part of the
consideration for the issue of the Notes.

          20.  GOVERNING LAW.  THE INTERNAL LAWS OF THE STATE OF NEW YORK
SHALL GOVERN THE INDENTURE AND THE NOTES WITHOUT REGARD TO CONFLICT OF LAW
PROVISIONS THEREOF.

          21.  AUTHENTICATION.  The Notes shall not be valid until
authenticated by the manual signature of an authorized officer of the Trustee
or an authenticating agent.

          22.  ABBREVIATIONS.  Customary abbreviations may be used in the
name of a 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).

          The Company will furnish to any Holder of the Notes upon written
request and without charge a copy of the Indenture.  Request may be made to:

     Invitrogen Corporation
     1600 Faraday Avenue
     Carlsbad, California  92008
     Attention: James R. Glynn
                Executive Vice President

                                        8
<PAGE>

                                  ASSIGNMENT FORM

                    To assign this Note, fill in the form below:

                    (I) or (we) assign and transfer this Note to

                     __________________________________________
                (INSERT ASSIGNEE'S SOCIAL SECURITY 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.

          Your Signature: __________________________________________________
          (SIGN EXACTLY AS YOUR NAME APPEARS ON THE OTHER SIDE OF THIS NOTE)

          Date: __________________

     Signature Guarantee: *____________________________________________

     In connection with any transfer of any of the Notes evidenced by this
     certificate occurring prior to the date that is two years after the later
     of the date of original issuance of such Notes and the last date, if any,
     on which such Notes were owned by the Company or any Affiliate of the
     Company, the undersigned confirms that such Notes are being transferred:

CHECK ONE BOX BELOW

     (1)  / /  to the Company or any subsidiary thereof,

     (2)  / /  to a qualified institutional buyer in compliance with Rule 144A,

     (3)  / /  outside the United States in compliance with Rule 904 under the
     Securities Act,

     (4)  / /  pursuant to the exemption from registration provided by Rule 144
     under the Securities Act (if available) or

     (5)  / /  pursuant to an effective registration statement under the
     Securities Act.

------------------
(*)  Signature must be guaranteed by a commercial bank, trust company or member
     firm of the New York Stock Exchange
<PAGE>

                                          ----------------------------
                                                  Signature

Signature Guarantee*

-----------------------------
Signature must be guaranteed

__________________________________________________________________

                TO BE COMPLETED BY PURCHASER IF (2) ABOVE IS CHECKED.

     The undersigned represents and warrants that it is purchasing this Note for
     its own account or an account with respect to which it exercises sole
     investment discretion and that it and any such account is a "qualified
     institutional buyer" within the meaning of Rule 144A under the Securities
     Act of 1933, and is aware that the sale to it is being made in reliance on
     Rule 144A and acknowledges that it has received such information regarding
     the Company as the undersigned has requested pursuant to Rule 144A or has
     determined not to request such information and that it is aware that the
     transferor is relying upon the undersigned's foregoing representations in
     order to claim the exemption from registration provided by Rule 144A.

Date:
     -----------------------

------------------
*    Signature must be guaranteed by a commercial bank, trust company or member
     firm of the New York Stock Exchange.

                    NOTICE: To be executed by an executive officer
<PAGE>

                          OPTION OF HOLDER TO ELECT PURCHASE

     If you want to elect to have this Note or a portion thereof repurchased by
     the Company pursuant to Section 3.09 or 4.07 of the Indenture, check the
     box: [ ]

     If the purchase is in part, indicate the portion (in denominations of
     $1,000 or any integral multiple thereof) to be purchased:
     ______________________

          Your Signature: __________________________________________________
          (SIGN EXACTLY AS YOUR NAME APPEARS ON THE OTHER SIDE OF THIS NOTE)

     Date:
           -------------------------

     Signature Guarantee:**/

------------------
**/  Signature must be guaranteed by a commercial bank, trust company or member
     firm of the New York Stock Exchange.
<PAGE>

                                 ELECTION TO CONVERT

To Invitrogen Corporation

     The undersigned owner of this Note hereby irrevocably exercises the option
     to convert this Note, or the portion below designated, into Common Stock of
     Invitrogen Corporation in accordance with the terms of the Indenture
     referred to in this Note, and directs that the shares issuable and
     deliverable upon conversion, together with any check in payment for
     fractional shares, be issued in the name of and delivered to the
     undersigned, unless a different name has been indicated in the assignment
     below.  If the shares are to be issued in the name of a person other than
     the undersigned, the undersigned will pay all transfer taxes payable with
     respect thereto.

     Any holder of Notes, upon the exercise of its conversion rights in
     accordance with the terms of the Indenture and the Note, agrees to be bound
     by the terms of the Registration Rights Agreement relating to the Common
     Stock issuable upon conversion of the Notes.

Date:

          in whole ___

                              Portions of Note to be converted ($1,000 or
                              integral multiples thereof): $______________
                              ____________________________________________
                              Signature

                              Please Print or Typewrite Name and Address,
                              Including Zip Code, and Social Security or Other
                              Identifying Number

                              ____________________________________________
                              ____________________________________________
                              ____________________________________________
                              Signature Guarantee:*_______________________

------------------
*    Signature must be guaranteed by a commercial bank, trust company or member
     firm of the New York Stock Exchange.
<PAGE>

                                     SCHEDULE A

                            SCHEDULE OF PRINCIPAL AMOUNT

     The initial principal amount of this Global Note shall be $172,500,000.
     The following increases or decreases in the principal amount of this Global
     Note have been made:

<TABLE>
<CAPTION>
-------------------------------------------------------------------------------
                                                  Signature of
    Amount of       Amount of                      authorized       Date of
   decrease in     increase in                     officer of       exchange
    principal       principal       Principal      Trustee or      following
 amount of this  amount of this  amount of this       Notes      such decrease
   Global Note     Global Note     Global Note      Custodian     or increase
-------------------------------------------------------------------------------
<S>              <C>             <C>              <C>            <C>
-------------------------------------------------------------------------------

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</TABLE><PAGE>

                               INVITROGEN CORPORATION

                                    $150,000,000

                                  Principal Amount

                   5 1/2% Convertible Subordinated Notes due 2007

                                 Purchase Agreement

                                 February 25, 2000

                            DONALDSON, LUFKIN & JENRETTE
                               SECURITIES CORPORATION
                              BEAR, STEARNS & CO. INC.
                               CHASE SECURITIES INC.
                             DAIN RAUSCHER INCORPORATED
                          U.S. BANCORP PIPER JAFFRAY INC.

<PAGE>

                   5 1/2% Convertible Subordinated Notes due 2007

                               INVITROGEN CORPORATION

                                 PURCHASE AGREEMENT

                                                              February 25, 2000

DONALDSON, LUFKIN & JENRETTE
    SECURITIES CORPORATION
BEAR, STEARNS & CO. INC.
CHASE SECURITIES INC.
DAIN RAUSCHER INCORPORATED
U.S. BANCORP PIPER JAFFRAY INC.
c/o Donaldson, Lufkin & Jenrette
    Securities Corporation
277 Park Avenue
New York, New York 10172

Dear Sirs:

              Invitrogen Corporation, a Delaware corporation (the "COMPANY"),
proposes to issue and sell to Donaldson, Lufkin & Jenrette Securities
Corporation ("DLJ"), Bear, Stearns & Co. Inc., Chase Securities Inc., Dain
Rauscher Incorporated and U.S. Bancorp Piper Jaffray Inc. (each an "INITIAL
PURCHASER" and, collectively, the "INITIAL PURCHASERS") an aggregate of
$150,000,000 in principal amount of its 5 1/2% Convertible Subordinated Notes
due 2007 (the "FIRM NOTES"), subject to the terms and conditions set forth
herein. The Company also proposes to issue and sell to the Initial Purchasers
not more than an additional $22,500,000 principal amount of its 5 1/2%
Convertible Subordinated Notes due 2007 (the "ADDITIONAL NOTES"), if
requested by the Initial Purchasers as provided in Section 2 hereof.  The
Firm Notes and the Additional Notes are herein collectively referred to as
the "NOTES".  The Notes are to be issued pursuant to the provisions of an
indenture (the "INDENTURE"), to be dated as of the Closing Date (as defined
below), between the Company, and State Street Bank and Trust Company of
California, N.A., as trustee (the "TRUSTEE"), pursuant to which the Notes, as
provided therein, will be convertible at the option of the holders thereof
into shares of the Company's common stock, par value $0.01 per share (the
"COMMON STOCK").  The Notes and the Common Stock issuable upon conversion
thereof are herein collectively referred to as the "SECURITIES".  The
Securities and the Indenture are more fully described in the Offering
Memorandum (as hereinafter defined).  Capitalized terms used but not defined
herein shall have the meanings given to such terms in the Indenture.

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       1.     OFFERING MEMORANDUM.  The Notes will be offered and sold to the
Initial Purchasers pursuant to one or more exemptions from the registration
requirements under the Securities Act of 1933, as amended (the "ACT").  The
Company has prepared a preliminary offering memorandum, dated February 15, 2000
(the "PRELIMINARY OFFERING MEMORANDUM") and a final offering memorandum, dated
February 25, 2000 (the "OFFERING MEMORANDUM"), relating to the Notes.

       Upon original issuance thereof, and until such time as the same is no
longer required pursuant to the Indenture, the Notes (and all securities issued
in exchange therefor, in substitution thereof or upon conversion thereof) shall
bear the following legend:

              "THIS NOTE (OR ITS PREDECESSOR) HAS NOT BEEN REGISTERED
       UNDER THE U.S. SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES
       ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED, SOLD, PLEDGED OR
       OTHERWISE TRANSFERRED WITHIN THE UNITED STATES OR TO, OR FOR THE
       ACCOUNT OR BENEFIT OF, U.S. PERSONS, EXCEPT AS SET FORTH IN THE
       NEXT SENTENCE HEREOF.  BY ITS ACQUISITION HEREOF OR OF A
       BENEFICIAL INTEREST HEREIN, THE HOLDER:

          (1) REPRESENTS THAT (A) IT IS A "QUALIFIED INSTITUTIONAL BUYER" (AS
          DEFINED IN RULE 144A UNDER THE SECURITIES ACT)(A "QIB"), (B) IT HAS
          ACQUIRED THIS NOTE IN AN OFFSHORE TRANSACTION IN COMPLIANCE WITH
          REGULATION S UNDER THE SECURITIES ACT OR (C) IT IS AN INSTITUTIONAL
          "ACCREDITED INVESTOR" (AS DEFINED IN RULE 501(A)(1), (2), (3) OR
          (7) OF REGULATION D UNDER THE SECURITIES ACT (AN "IAI"),

          (2) AGREES THAT IT WILL NOT RESELL OR OTHERWISE TRANSFER THIS NOTE
          EXCEPT (A) TO THE COMPANY OR ANY OF ITS SUBSIDIARIES, (B) TO A
          PERSON WHOM THE SELLER REASONABLY BELIEVES IS A QIB PURCHASING FOR
          ITS OWN ACCOUNT OR FOR THE ACCOUNT OF A QIB IN A TRANSACTION
          MEETING THE REQUIREMENTS OF RULE 144A, (C) IN AN OFFSHORE
          TRANSACTION MEETING THE REQUIREMENTS OF RULE 903 OR 904 OF THE
          SECURITIES ACT, (D) IN A TRANSACTION MEETING THE REQUIREMENTS OF
          RULE 144 UNDER THE SECURITIES ACT, (E) TO AN IAI THAT, PRIOR TO
          SUCH TRANSFER, FURNISHES THE TRUSTEE A SIGNED LETTER CONTAINING
          CERTAIN REPRESENTATIONS AND AGREEMENTS RELATING TO THE TRANSFER OF
          THIS NOTE (THE FORM OF WHICH CAN BE OBTAINED FROM THE TRUSTEE) AND,
          IF THE COMPANY SO REQUESTS AN OPINION OF COUNSEL ACCEPTABLE TO THE
          COMPANY THAT SUCH TRANSFER IS IN COMPLIANCE WITH THE SECURITIES
          ACT, (F) IN ACCORDANCE WITH ANOTHER EXEMPTION FROM THE REGISTRATION
          REQUIREMENTS OF THE SECURITIES ACT (AND BASED UPON AN OPINION OF
          COUNSEL ACCEPTABLE TO THE COMPANY) OR (G) PURSUANT TO AN EFFECTIVE
          REGISTRATION STATEMENT AND, IN EACH CASE, IN ACCORDANCE

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          WITH THE APPLICABLE SECURITIES LAWS OF ANY STATE OF THE UNITED
          STATES OR ANY OTHER APPLICABLE JURISDICTION AND

          (3) AGREES THAT IT WILL DELIVER TO EACH PERSON TO WHOM THIS NOTE OR
          AN INTEREST HEREIN IS TRANSFERRED A NOTICE SUBSTANTIALLY TO THE
          EFFECT OF THIS LEGEND.

       AS USED HEREIN, THE TERMS "OFFSHORE TRANSACTION" AND "UNITED
       STATES" HAVE THE MEANINGS GIVEN TO THEM BY RULE 902 OF REGULATION
       S UNDER THE SECURITIES ACT.  THE INDENTURE CONTAINS A PROVISION
       REQUIRING THE TRUSTEE TO REFUSE TO REGISTER ANY TRANSFER OF THIS
       NOTE IN VIOLATION OF THE FOREGOING."

       2.     AGREEMENTS TO SELL AND PURCHASE.  (a)  On the basis of the
representations, warranties and covenants contained in this Agreement, and
subject to the terms and conditions contained herein, the Company agrees to
issue and sell to the Initial Purchasers, and the Initial Purchasers agree,
severally and not jointly, to purchase from the Company, the principal amount of
Firm Notes set forth opposite its name as set forth on Schedule A hereto at a
purchase price equal to 97.0% of the principal amount thereof (the "PURCHASE
PRICE").

                     (b)    On the basis of the representations and
warranties contained in this Agreement, and subject to its terms and
conditions, (i) the Company agrees to issue and sell the Additional Notes and
(ii) the Initial Purchasers shall have a right, but not the obligation, to
purchase, severally and not jointly, the Additional Notes, from the Company
at the Purchase Price. Additional Notes may be purchased solely for the
purpose of covering over-allotments made in connections with the offering of
the Firm Notes.  The Initial Purchasers may exercise their right to purchase
Additional Notes in whole or in part from time to time by giving written
notice thereof to the Company at any time within 30 days after the date of
this Agreement.  DLJ shall give any such notice on behalf of the Initial
Purchasers and such notice shall specify the aggregate principal amount of
Additional Notes to be purchased pursuant to such exercise and the date for
payment and delivery thereof.  The date specified in any such notice shall be
a business day (i) no earlier than the Closing Date (as hereinafter defined),
(ii) no later than ten business days after such notice has been given and
(iii) no earlier than two business days after such notice has been given.  If
any Additional Notes are to be purchased, each Initial Purchaser, severally
and not jointly, agrees to purchase from the Company the principal amount of
Additional Notes which bears the same proportion to the total principal
amount of Additional Notes to be purchased from the Company as the principal
amount of Firm Notes set forth opposite the name of such Initial Purchaser in
Schedule A bears to the total principal amount of Firm Notes.

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<PAGE>

       3.     TERMS OF OFFERING.  The Initial Purchasers have advised the
Company that the Initial Purchasers will make offers (the "EXEMPT RESALES") of
the Notes purchased hereunder on the terms set forth in the Offering Memorandum,
as amended or supplemented, solely to persons whom the Initial Purchaser
reasonably believe to be "qualified institutional buyers" as defined in Rule
144A under the Act ("QIBS") (such persons being referred to herein as the
"ELIGIBLE PURCHASERS").  The Initial Purchasers will offer the Notes to Eligible
Purchasers initially at a price equal to 100% of the principal amount thereof.
Such price may be changed at any time without notice.

       Holders (including subsequent transferees) of the Securities will have
the registration rights set forth in the registration rights agreement (the
"REGISTRATION RIGHTS AGREEMENT"), to be dated the Closing Date, in substantially
the form of Exhibit A hereto, for so long as such Securities constitute
"TRANSFER RESTRICTED SECURITIES" (as defined in the Registration Rights
Agreement).  Pursuant to the Registration Rights Agreement, the Company will
agree to file with the Securities and Exchange Commission (the "COMMISSION")
under the circumstances set forth therein, a shelf registration statement
pursuant to Rule 415 under the Act (the "REGISTRATION STATEMENT") relating to
the resale by certain holders of the Securities and to use its best efforts to
cause such Registration Statements to be declared and remain effective and
usable for the periods specified in the Registration Rights Agreement.  This
Agreement, the Indenture, the Notes, and the Registration Rights Agreement are
hereinafter sometimes referred to collectively as the "OPERATIVE DOCUMENTS"

       4.     DELIVERY AND PAYMENT.

                     (a)    Delivery of, and payment of the Purchase Price for,
the Firm Notes shall be made at the offices of Gray Cary Ware & Freidenrich LLP,
4365 Executive Drive, Suite 1600, San Diego, California 92121-2189 or such other
location as may be mutually acceptable.  Such delivery and payment shall be made
at 9:00 a.m. New York City time, on March 1, 2000 or at such other time on the
same date or such other date as shall be agreed upon by the Initial Purchasers
and the Company shall agree in writing.  The time and date of such delivery and
the payment for the Firm Notes are herein called the "CLOSING DATE".

                     (b)    Delivery of, and payment for, any Additional Notes
to be purchased by the Initial Purchasers shall be made at the offices of Gray
Cary Ware & Freidenrich LLP, 4365 Executive Drive, Suite 1600, San Diego,
California 92121-2189 at 9:00 a.m. New York City time, on the date specified in
the exercise notice given by DLJ pursuant to Section 2(b) or such other time on
the same or such other date as the Initial Purchasers and the Company shall
agree in writing.  The time and date of delivery and payment for any Additional
Notes are hereinafter referred to as an "OPTION CLOSING DATE".

                     (c)    One or more of the Notes in definitive global form,
registered in the name of Cede & Co., as nominee of the Depository Trust Company
("DTC"), having an aggregate principal amount corresponding to the aggregate
principal amount of the Notes (collectively, the "GLOBAL NOTE"), shall be
delivered by the Company to the Initial Purchasers (or as the Initial Purchasers
direct) in each case with any transfer taxes thereon duly paid by the Company
against payment by the Initial Purchasers of the Purchase Price thereof by wire
transfer in same day funds

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<PAGE>

to the order of the Company.  The Global Note shall be made available to the
Initial Purchasers for inspection not later than 9:30 a.m., New York City
time, on the business day immediately preceding the Closing Date.

       5.     AGREEMENTS OF THE COMPANY  The Company hereby agrees with the
Initial Purchasers as follows:

                     (a)    To advise the Initial Purchasers promptly and, if
requested by the Initial Purchasers, confirm such advice in writing, (i) of the
issuance by any state securities commission of any stop order suspending the
qualification or exemption from qualification of any Notes for offering or sale
in any jurisdiction designated by the Initial Purchasers pursuant to Section
5(e) hereof, or the initiation of any proceeding by any state securities
commission or any other federal or state regulatory authority for such purpose
and (ii) of the happening of any event during the period referred to in Section
5(c) below that makes any statement of a material fact made in the Preliminary
Offering Memorandum or the Offering Memorandum untrue or that requires any
additions to or changes in the Preliminary Offering Memorandum or the Offering
Memorandum in order to make the statements therein not misleading.  The Company
shall use its best efforts to prevent the issuance of any stop order or order
suspending the qualification or exemption of any Notes under any state
securities or Blue Sky laws and, if at any time any state securities commission
or other federal or state regulatory authority shall issue an order suspending
the qualification or exemption of any Notes under any state securities or Blue
Sky laws, the Company shall use its best efforts to obtain the withdrawal or
lifting of such order at the earliest possible time.

                     (b)    To furnish the Initial Purchasers and those persons
identified by the Initial Purchasers to the Company as many copies of the
Preliminary Offering Memorandum and the Offering Memorandum, any documents
incorporated by reference therein, and any amendments or supplements thereto, as
the Initial Purchasers may reasonably request for the time period specified in
Section 5(c).  Subject to the Initial Purchasers' compliance with its
representations and warranties and agreements set forth in Section 7 hereof, the
Company consents to the use of the Preliminary Offering Memorandum and the
Offering Memorandum, any documents incorporated by reference therein, and any
amendments and supplements thereto required pursuant hereto, by the Initial
Purchasers in connection with Exempt Resales.

                     (c)    During such period as in the opinion of counsel for
the Initial Purchasers an Offering Memorandum is required by law to be delivered
in connection with Exempt Resales by the Initial Purchasers (i) not to make any
amendment or supplement to the Offering Memorandum of which the Initial
Purchasers shall not previously have been advised or to which the Initial
Purchasers shall reasonably object after being so advised and (ii) to prepare
promptly upon the Initial Purchasers' reasonable request, any amendment or
supplement to the Offering Memorandum which may be necessary or advisable in
connection with such Exempt Resales.

                     (d)    If, during the period referred to in Section 5(c)
above, any event shall occur or condition shall exist as a result of which, in
the opinion of counsel to the Initial Purchasers, it

                                       5
<PAGE>

becomes necessary to amend or supplement the Offering Memorandum in order to
make the statements therein, in the light of the circumstances when such
Offering Memorandum is delivered to an Eligible Purchaser, not misleading, or
if, in the opinion of counsel to the Initial Purchasers, it is necessary to
amend or supplement the Offering Memorandum to comply with any applicable
law, forthwith to prepare an appropriate amendment or supplement to such
Offering Memorandum so that the statements therein, as so amended or
supplemented, will not, in the light of the circumstances when it is so
delivered, be misleading, or so that such Offering Memorandum will comply
with applicable law, and to furnish to the Initial Purchasers and such other
persons as the Initial Purchasers may designate such number of copies thereof
as the Initial Purchasers may reasonably request.

                     (e)    Prior to the sale of all Notes pursuant to Exempt
Resales as contemplated hereby, to cooperate with the Initial Purchasers and
counsel to the Initial Purchasers in connection with the registration or
qualification of the Notes for offer and sale to the Initial Purchasers and
pursuant to Exempt Resales under the securities or Blue Sky laws of such
jurisdictions as the Initial Purchasers may request and to continue such
registration or qualification in effect so long as required for Exempt Resales
and to file such consents to service of process or other documents as may be
necessary in order to effect such registration or qualification; PROVIDED,
HOWEVER, that the Company shall not be required in connection therewith to
qualify as a foreign corporation in any jurisdiction in which it is not now so
qualified or to take any action that would subject it to general consent to
service of process or taxation other than as to matters and transactions
relating to the Preliminary Offering Memorandum, the Offering Memorandum or
Exempt Resales, in any jurisdiction in which it is not now so subject.

                     (f)    So long as the Notes are outstanding, (i) to mail
and make generally available as soon as practicable after the end of each fiscal
year to the record holders of the Notes a financial report of the Company and
its subsidiaries on a consolidated basis (and a similar financial report of all
unconsolidated subsidiaries, if any), all such financial reports to include a
consolidated balance sheet, a consolidated statement of operations, a
consolidated statement of cash flows and a consolidated statement of
shareholders' equity as of the end of and for such fiscal year, together with
comparable information as of the end of and for the preceding year, certified by
the Company's independent public accountants and (ii) to mail and make generally
available as soon as practicable after the end of each quarterly period (except
for the last quarterly period of each fiscal year) to such holders, a
consolidated balance sheet, a consolidated statement of operations and a
consolidated statement of cash flows (and similar financial reports of all
unconsolidated subsidiaries, if any) as of the end of and for such period, and
for the period from the beginning of such year to the close of such quarterly
period, together with comparable information for the corresponding periods of
the preceding year.

                     (g)    So long as the Notes are outstanding, to furnish to
the Initial Purchasers as soon as available, copies of all reports or other
communications furnished by the Company to its security holders or furnished to
or filed with the Commission or any national securities exchange on which any
class of securities of the Company is listed and such other publicly available
information concerning the Company and/or its subsidiaries as the Initial
Purchasers may reasonably request.

                     (h)    So long as any of the Notes remain outstanding and
during any period in which the Company is not subject to Section 13 or 15(d) of
the Securities Exchange Act of 1934, as amended (the "EXCHANGE ACT"), to make
available to any holder of Securities in

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<PAGE>

connection with any sale thereof and any prospective purchaser of such
Securities from such holder, the information ("RULE 144A INFORMATION")
required by Rule 144A(d)(4) under the Act.

                     (i)    Whether or not the transactions contemplated in this
Agreement are consummated or this Agreement is terminated, to pay or cause to be
paid all reasonable expenses incident to the performance of the obligations of
the Company under this Agreement, including: (i) the reasonable fees,
disbursements and expenses of counsel to the Company and accountants of the
Company in connection with the sale and delivery of the Notes to the Initial
Purchasers and pursuant to Exempt Resales, and all other fees and expenses in
connection with the preparation, printing, filing and distribution of the
Preliminary Offering Memorandum, the Offering Memorandum and all amendments and
supplements to any of the foregoing (including financial statements), including
the mailing and delivering of copies thereof to the Initial Purchasers and
persons designated by them in the quantities specified herein, (ii) all costs
and expenses related to the transfer and delivery of the Notes to the Initial
Purchasers and pursuant to Exempt Resales, including any transfer or other taxes
payable thereon, (iii) all costs of printing or producing this Agreement, the
other Operative Documents and any other agreements or documents in connection
with the offering, purchase, sale or delivery of the Securities (other than the
fees, disbursements and expenses of counsel to the Initial Purchasers, except as
provided in clause (iv) below), (iv) all expenses in connection with the
registration or qualification of the Securities for offer and sale under the
securities or Blue Sky laws of the several states and all costs of printing or
producing any preliminary and supplemental Blue Sky memoranda in connection
therewith (including the filing fees and fees and disbursements of counsel for
the Initial Purchasers in connection with such registration or qualification and
memoranda relating thereto), (v) the cost of printing certificates representing
the Securities, (vi) all expenses and listing fees in connection with the
application for quotation of the Notes in the Nationl Association of Securities
Dealers, Inc. ("NASD") Automated Quotation System - PORTAL ("PORTAL"), (vii) the
fees and expenses of the Trustee and the Trustee's counsel in connection with
the Indenture and the Notes, (viii) the costs and charges of any transfer agent,
registrar and/or depositary (including DTC), (ix) any fees charged by rating
agencies for the rating of the Notes, (x) all costs and expenses of the
Registration Statement, as set forth in the Registration Rights Agreement, (xi)
all expenses and listing fees in connection with the application for listing the
Common Stock on the NASDAQ National Market and (xii) and all other costs and
expenses incident to the performance of the obligations of the Company hereunder
for which provision is not otherwise made in this Section.

                     (j)    To use its best efforts to effect the inclusion of
the Notes in PORTAL and to maintain the listing of the Notes on PORTAL for so
long as the Notes are outstanding.

                     (k)    To obtain the approval of DTC for "book-entry"
transfer of the Notes, and to comply with all of its agreements set forth in the
representation letters of the Company to DTC relating to the approval of the
Notes by DTC for "book-entry" transfer.

                     (l)    To cause the Common Stock issuable upon conversion
of the Notes to be duly included for quotation on the Nasdaq Stock Market's
National Market (the "NASDAQ NATIONAL MARKET") prior to the Firm Closing Date
subject to notice of official issuance.  The Company will ensure that such
Common Stock remain included for quotation on the Nasdaq

                                      7
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National Market or any other national securities exchange following the Firm
Closing Date for so long as any shares of Common Stock remain registered under
the Exchange Act.

                     (m)    The Company shall not (i) offer, pledge, sell,
contract to sell, sell any option or contract to purchase, purchase any option
or contract to sell, grant any option, right or warrant to purchase, or
otherwise transfer or dispose of, directly or indirectly, any shares of Common
Stock or any securities convertible into or exercisable or exchangeable for
Common Stock or (ii) enter into any swap or other arrangement that transfers all
or a portion of the economic consequences associated with the ownership of any
Common Stock (regardless of whether any of the transactions described in clause
(i) or (ii) is to be settled by the delivery of Common Stock, or such other
securities, in cash or otherwise), except to the Initial Purchasers pursuant to
this Agreement, for a period of 90 days after the Closing Date without the prior
written consent of DLJ.  Notwithstanding the foregoing, during such period (i)
the Company  may grant stock options pursuant to the Company's existing stock
option plans or other employee benefit plans and (ii) the Company may issue
shares of Common Stock upon the exercise of an option or warrant or the
conversion of a security outstanding on the date hereof.  Other than pursuant to
the Registration Rights Agreement, the Company also agrees not to file any
registration statement with respect to any shares of Common Stock or any
securities convertible into or exercisable or exchangeable for Common Stock for
a period of 90 days after the Closing Date without the prior written consent of
DLJ.  The Company shall, prior to or concurrently with the execution of this
Agreement, deliver an agreement executed by each of the directors and officers
of the Company to the effect that such person will not, during the period
commencing on the date such person signs such agreement and ending 90 days after
the Closing Date without the prior written consent of DLJ, (A) engage in any of
the transactions described in the first sentence of this paragraph or (B) make
any demand for, or exercise any right with respect to, the registration of any
shares of Common Stock or any securities convertible into or exercisable or
exchangeable for Common Stock.

                     (n)    Not to sell, offer for sale or solicit offers to buy
or otherwise negotiate in respect of any security (as defined in the Act) that
would be integrated with the sale of the Notes to the Initial Purchasers or
pursuant to Exempt Resales in a manner that would require the registration of
any such sale of the Notes under the Act.

                     (o)    Not to voluntarily claim, and to actively resist any
attempts to claim, the benefit of any usury laws against the holders of any
Notes.

                     (p)    To comply with all of its agreements set forth in
the Registration Rights Agreement.

                     (q)    To use its best efforts to do and perform all things
required or necessary to be done and performed under this Agreement by it prior
to the Closing Date and to satisfy all conditions precedent to the delivery of
the Notes.

       6.     REPRESENTATIONS, WARRANTIES AND AGREEMENTS OF THE COMPANY.  As of
the date hereof, the Company represents and warrants to, and agrees with, the
Initial Purchasers that:

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                     (a)    The Preliminary Offering Memorandum and the
Offering Memorandum do not, and any supplement or amendment to them will not,
contain any untrue statement of a material fact or omit to state any material
fact required to be stated therein or necessary to make the statements
therein, in the light of the circumstances under which they were made, not
misleading, except that the representations and warranties contained in this
paragraph (a) shall not apply to statements in or omissions from the
Preliminary Offering Memorandum or the Offering Memorandum (or any supplement
or amendment thereto) based upon information relating to the Initial
Purchasers furnished to the Company in writing by the Initial Purchasers
expressly for use therein.  The Company acknowledges for all purposes of this
Agreement (including Section 8 hereof) that the statements with respect to
price and underwriting discounts and commissions and the last paragraph all
as set forth on the cover page and in paragraphs four and eight under the
caption "Plan of Distribution" in the Offering Memorandum (the "INITIAL
PURCHASER INFORMATION") constitute the only written information furnished to
the Company by or on behalf of the Initial Purchasers expressly for use in
the Preliminary Offering Memorandum or Offering Memorandum (or any amendment
or supplement to any of them) and that the Initial Purchasers shall not be
deemed to have provided any other information (and therefore are not
responsible for any such statements or omissions).  No stop order preventing
the use of the Preliminary Offering Memorandum or the Offering Memorandum, or
any amendment or supplement thereto, or any order asserting that any of the
transactions contemplated by this Agreement are subject to the registration
requirements of the Act, has been issued.

                     (b)    Each of the Company and its subsidiaries has been
duly incorporated, is validly existing as a corporation in good standing
under the laws of its jurisdiction of incorporation and has the corporate
power and authority to carry on its business as described in the Preliminary
Offering Memorandum and the Offering Memorandum and to own, lease and operate
its properties, and each is duly qualified and is in good standing as a
foreign corporation authorized to do business in each jurisdiction in which
the nature of its business or its ownership or leasing of property requires
such qualification, except where the failure to be so qualified would not
have a material adverse effect on the business, prospects, financial
condition or results of operations of the Company and its subsidiaries, taken
as a whole (a "MATERIAL ADVERSE EFFECT").

                     (c)    All outstanding shares of capital stock of the
Company have been duly authorized and validly issued and are fully paid,
non-assessable and not subject to any preemptive or similar rights.

                     (d)    The entities listed on Schedule B hereto are the
only subsidiaries, direct or indirect, of the Company.  All of the
outstanding shares of capital stock of each of the Company's subsidiaries
have been duly authorized and validly issued and are fully paid and
non-assessable, and are owned by the Company, directly or indirectly through
one or more subsidiaries, free and clear of any security interest, claim,
lien, encumbrance or adverse interest of any nature (each, a "LIEN").

                     (e)    This Agreement has been duly authorized, executed
and delivered by the Company.

                                      9

<PAGE>

                     (f)    The Indenture has been duly authorized by the
Company and, on the Closing Date, will have been validly executed and
delivered by the Company.  When the Indenture has been duly executed and
delivered by the Company, the Indenture will be a valid and binding agreement
of the Company, enforceable against the Company in accordance with its terms
except as (i) the enforceability thereof may be limited by bankruptcy,
insolvency or similar laws affecting creditors' rights generally and (ii)
rights of acceleration and the availability of equitable remedies may be
limited by equitable principles of general applicability.  On the Closing
Date, the Indenture will conform in all material respects to the requirements
of the Trust Indenture Act of 1939, as amended (the "TIA" or "TRUST INDENTURE
ACT"), and the rules and regulations of the Commission applicable to an
indenture which is qualified thereunder.

                     (g)    The Notes have been duly authorized and, on the
Closing Date, will have been validly executed and delivered by the Company.
When the Notes have been issued, executed and authenticated in accordance
with the provisions of the Indenture and delivered to and paid for by the
Initial Purchasers in accordance with the terms of this Agreement, the Notes
will be entitled to the benefits of the Indenture and will be valid and
binding obligations of the Company, enforceable in accordance with their
terms except as (i) the enforceability thereof may be limited by bankruptcy,
insolvency or similar laws affecting creditors' rights generally and (ii)
rights of acceleration and the availability of equitable remedies may be
limited by equitable principles of general applicability.  On the Closing
Date, the Notes will conform as to legal matters to the description thereof
contained in the Offering Memorandum.

                     (h)    The Notes are convertible into Common Stock in
accordance with the terms of the Indenture; the shares of Common Stock
initially issuable upon conversion of the Notes have been duly authorized and
reserved for issuance upon such conversion and, when issued upon such
conversion, will be validly issued, fully paid and nonassessable, will
conform to the description thereof contained in the Offering Memorandum and
will be duly authorized for listing on the NASDAQ National Market, subject to
notice of official issuance; the Company has the authorized and outstanding
capital stock as set forth in the Offering Memorandum; and the stockholders
of the Company or other holders of the Company's securities have no
pre-emptive or similar rights with respect to the Notes or the Common Stock
issuable upon the Notes.

                     (i)    The Registration Rights Agreement has been duly
authorized by the Company and, on the Closing Date, will have been duly
executed and delivered by the Company.  When the Registration Rights
Agreement has been duly executed and delivered, the Registration Rights
agreement will be a valid and binding agreement of the Company, enforceable
against the Company in accordance with its terms except as (i) the
enforceability thereof may be limited by bankruptcy, insolvency or similar
laws affecting creditors' rights generally and (ii) rights of acceleration
and the availability of equitable remedies may be limited by equitable
principles of general applicability.  On the Closing Date, the Registration
Rights Agreement will conform as to legal matters to the description thereof
in the Offering Memorandum.

                     (j)    The authorized capital stock of the Company
conforms as to legal matters to the description thereof contained in the
Offering Memorandum.

                                      10

<PAGE>

                     (k)    Neither the Company nor any of its subsidiaries
is in violation of its respective charter or by-laws or in default in the
performance of any obligation, agreement, covenant or condition contained in
any indenture, loan agreement, mortgage, lease or other agreement or
instrument to which the Company or any of its subsidiaries is a party or by
which the Company or any of its subsidiaries or their respective property is
bound and that is material to the Company and its subsidiaries, taken as a
whole, except for such violations or defaults which, singly or in the
aggregate, would not have a Material Adverse Effect.

                     (l)    The execution, delivery and performance the
Operative Documents by the Company, compliance by the Company with all
provisions hereof and thereof and the consummation of the transactions
contemplated hereby and thereby will not (i) require any consent, approval,
authorization or other order of, or qualification with, any court or
governmental body or agency (except such as may be required under the
securities or Blue Sky laws of the various states), (ii) conflict with or
constitute a breach of any of the terms or provisions of, or a default under,
the charter or by-laws of the Company or any of its subsidiaries or any
indenture, loan agreement, mortgage, lease or other agreement or instrument
to which the Company or any of its subsidiaries is a party or by which the
Company or any of its subsidiaries or their respective property is bound and
that is material to the Company and its subsidiaries, taken as a whole, (iii)
violate or conflict with any applicable law or any rule, regulation,
judgment, order or decree of any court or any governmental body or agency
having jurisdiction over the Company, any of its subsidiaries or their
respective property, (iv) result in the imposition or creation of (or the
obligation to create or impose) a Lien under, any agreement or instrument to
which the Company or any of its subsidiaries is a party or by which the
Company or any of its subsidiaries or their respective property is bound, or
(v) result in the termination, suspension or revocation of any Material
Authorization (as defined below) of the Company or any of its subsidiaries or
result in any other impairment of the rights of the holder of any such
Material Authorization, except for such breaches, violations, terminations,
suspensions, revocations or defaults which, singly or in the aggregate, would
not have a Material Adverse Effect.

                     (m)    There are no legal or governmental proceedings
pending or, to the Company's knowledge, threatened to which the Company or
any of its subsidiaries is or could be a party or to which any of their
respective property is or could be subject, which might result, singly or in
the aggregate, in a Material Adverse Effect.

                     (n)    The Company and its subsidiaries have good and
marketable title in fee simple to all real property and good and marketable
title to all personal property owned by them which is material to the
business of the Company and its subsidiaries, in each case free and clear of
all liens, encumbrances and defects except such as are described in the
Offering Memorandum or such as do not materially affect the value of such
property and do not interfere with the use made and proposed to be made of
such property by the Company and its subsidiaries; and any real property and
buildings held under lease by the Company and its subsidiaries are held by
them under valid, subsisting and enforceable leases with such exceptions as
are not material and do not interfere with the use made and proposed to be
made of such property and buildings by the Company and its subsidiaries, in
each case except as described in the Offering Memorandum.

                                      11

<PAGE>

                     (o)    The Company and its subsidiaries own or possess,
or can acquire on reasonable terms, all patents, patent rights, licenses,
inventions, copyrights, know-how (including trade secrets and other
unpatented and/or unpatentable proprietary or confidential information,
systems or procedures), trademarks, service marks and trade names
("INTELLECTUAL PROPERTY") currently employed by them in connection with the
business now operated by them, except where the failure to own or possess or
otherwise be able to acquire such Intellectual Property would not, singly or
in the aggregate, have a Material Adverse Effect; and neither the Company nor
any of its subsidiaries has received any notice of infringement of or
conflict with asserted rights of others with respect to any of such
Intellectual Property which, singly or in the aggregate, if the subject of an
unfavorable decision, ruling or finding, would have a Material Adverse Effect.

                     (p)    The Company and each of its subsidiaries are
insured by insurers of recognized financial responsibility against such
losses and risks and in such amounts as are prudent and customary in the
businesses in which they are engaged; and neither the Company nor any of its
subsidiaries (i) has received notice from any insurer or agent of such
insurer that substantial capital improvements or other material expenditures
will have to be made in order to continue such insurance or (ii) has any
reason to believe that it will not be able to renew its existing insurance
coverage as and when such coverage expires or to obtain similar coverage from
similar insurers at a cost that would not have a Material Adverse Effect.

                     (q)    Except as disclosed in the Offering Memorandum,
no relationship, direct or indirect, exists between or among the Company or
any of its subsidiaries on the one hand, and the directors, officers,
stockholders, customers or suppliers of the Company or any of its
subsidiaries on the other hand, which would be required by the Act to be
described in the Offering Memorandum if the Offering Memorandum were a
prospectus included in a registration statement on Form S-1 file with the
Commission.

                     (r)    The Company and each of its subsidiaries
maintains a system of internal accounting controls sufficient to provide
reasonable assurance that (i) transactions are executed in accordance with
management's general or specific authorizations; (ii) transactions are
recorded as necessary to permit preparation of financial statements in
conformity with generally accepted accounting principles and to maintain
asset accountability; (iii) access to assets is permitted only in accordance
with management's general or specific authorization; and (iv) the recorded
accountability for assets is compared with the existing assets at reasonable
intervals and appropriate action is taken with respect to any differences.

                     (s)    All material tax returns required to be filed by
the Company and each of its subsidiaries in any jurisdiction have been filed,
other than those filings being contested in good faith, and all material
taxes, including withholding taxes, penalties and interest, assessments, fees
and other charges due pursuant to such returns or pursuant to any assessment
received by the Company or any of its subsidiaries have been paid, other than
those being contested in good faith and for which adequate reserves have been
provided.

                     (t)    Neither the Company nor any of its subsidiaries
has violated any foreign, federal, state or local law or regulation relating
to the protection of human health and safety, the environment or hazardous or
toxic substances or wastes, pollutants or contaminants

                                      12

<PAGE>

("ENVIRONMENTAL LAWS"), any provisions of the Employee Retirement Income
Security Act of 1974, as amended ("ERISA"), or any provisions of the Foreign
Corrupt Practices Act or the rules and regulations promulgated thereunder,
except for such violations which, singly or in the aggregate, would not have
a Material Adverse Effect.

                     (u)    Each of the Company and its subsidiaries has such
permits, licenses, consents, exemptions, franchises, authorizations and other
approvals (each, a "MATERIAL AUTHORIZATION") of, and has made all filings
with and notices to, all governmental or regulatory authorities and
self-regulatory organizations and all courts and other tribunals, including
without limitation, under any applicable Environmental Laws, as are necessary
to own, lease, license and operate its respective properties and to conduct
its business, except where the failure to have any such Material
Authorization or to make any such filing or notice would not, singly or in
the aggregate, have a Material Adverse Effect. Each such Material
Authorization is valid and in full force and effect and each of the Company
and its subsidiaries is in compliance with all the terms and conditions
thereof and with the rules and regulations of the authorities and governing
bodies having jurisdiction with respect thereto; and no event has occurred
(including, without limitation, the receipt of any notice from any authority
or governing body) which allows or, after notice or lapse of time or both,
would allow, revocation, suspension or termination of any such Material
Authorization or results or, after notice or lapse of time or both, would
result in any other impairment of the rights of the holder of any such
Material Authorization held by the Company or its subsidiaries; and such
Material Authorizations held by the Company or its subsidiaries contain no
restrictions that are burdensome to the Company or any of its subsidiaries;
except where such failure to be valid and in full force and effect or to be
in compliance, the occurrence of any such event or the presence of any such
restriction would not, singly or in the aggregate, have a Material Adverse
Effect.

                     (v)    There are no costs or liabilities associated with
Environmental Laws (including, without limitation, any capital or operating
expenditures required for clean-up, closure of properties or compliance with
Environmental Laws or any Material Authorization, any related constraints on
operating activities and any potential liabilities to third parties) which
would, singly or in the aggregate, have a Material Adverse Effect.

                     (w)    The accountants, Arthur Andersen LLP, that have
certified the financial statements and supporting schedules included in the
Preliminary Offering Memorandum and the Offering Memorandum are independent
public accountants with respect to the Company, as required by the Act and
the Exchange Act.  The historical financial statements, together with related
schedules and notes, set forth in the Preliminary Offering Memorandum and the
Offering Memorandum comply as to form in all material respects with the
requirements applicable to registration statements on Form S-1 under the Act.

                     (x)    The historical financial statements, together
with related schedules and notes forming part of the Offering Memorandum (and
any amendment or supplement thereto), present fairly the consolidated
financial position, results of operations and changes in financial position
of the Company and its subsidiaries on the basis stated or incorporated by
reference in the Offering Memorandum at the respective dates or for the
respective periods to which they apply; such statements and related schedules
and notes have been prepared in accordance with generally

                                      13

<PAGE>

accepted accounting principles consistently applied throughout the periods
involved, except as disclosed therein; and the other financial and
statistical information and data set forth or incorporated by reference in
the Offering Memorandum (and any amendment or supplement thereto) are, in all
material respects, accurately presented and prepared on a basis consistent
with such financial statements and the books and records of the Company.

                     (y)    The PRO FORMA financial statements included in
the Preliminary Offering Memorandum and the Offering Memorandum have been
prepared on a basis consistent with the historical financial statements of
the Company and its subsidiaries and give effect to assumptions used in the
preparation thereof on a reasonable basis and in good faith and present
fairly the historical and proposed transactions contemplated by the
Preliminary Offering Memorandum and the Offering Memorandum; and such PRO
FORMA financial statements comply as to form in all material respects with
the requirements applicable to PRO FORMA financial statements included in
registration statements on Form S-1 under the Act.  The other PRO FORMA
financial and statistical information and data included in the Offering
Memorandum are, in all material respects, accurately presented and prepared
on a basis consistent with the PRO FORMA financial statements.

                     (z)    The Company is not and, after giving effect to
the offering and sale of the Notes and the application of the net proceeds
thereof as described in the Offering Memorandum, will not be, an "investment
company," as such term is defined in the Investment Company Act of 1940, as
amended.

                     (aa)   Except as set forth in the Offering Memorandum,
there are no contracts, agreements or understandings between the Company and
any person granting such person the right to require the Company to file a
registration statement under the Act with respect to any securities of the
Company or to require the Company to include such securities with the Notes
registered pursuant to any Registration Statement.

                     (bb)   Neither the Company nor any of its subsidiaries
nor any agent thereof acting on the behalf of them has taken, and none of
them will take, any action that might cause this Agreement or the issuance or
sale of the Notes to violate Regulation G (12 C.F.R. Part 207), Regulation T
(12 C.F.R. Part 220), Regulation U (12 C.F.R. Part 221) or Regulation X (12
C.F.R. Part 224) of the Board of Governors of the Federal Reserve System.

                     (cc)   No "nationally recognized statistical rating
organization" as such term is defined for purposes of Rule 436(g)(2) under
the Act (i) has imposed (or has informed the Company that it is considering
imposing) any condition (financial or otherwise) on the Company's retaining
any rating assigned to the Company, any securities of the Company or (ii) has
indicated to the Company that it is considering (a) the downgrading,
suspension, or withdrawal of, or any review for a possible change that does
not indicate the direction of the possible change in, any rating so assigned
or (b) any change in the outlook for any rating of the Company, or any
securities of the Company.

                     (dd)   Since the respective dates as of which
information is given in the Offering Memorandum other than as set forth in
the Offering Memorandum (exclusive of any amendments or supplements thereto
subsequent to the date of this Agreement), (i) there has not

                                      14

<PAGE>

occurred any material adverse change or, to the knowledge of the Company, any
development involving a prospective material adverse change in the condition,
financial or otherwise, or the earnings, business, management or operations
of the Company and its subsidiaries, taken as a whole, (ii) there has not
been any material adverse change or, to the knowledge of the Company, any
development involving a prospective material adverse change in the capital
stock or in the long-term debt of the Company or any of its subsidiaries and
(iii) neither the Company nor any of its subsidiaries has incurred any
material liability or obligation, direct or contingent.

                     (ee)   Each of the Preliminary Offering Memorandum and
the Offering Memorandum, as of its date, contains all the information
specified in, and meeting the requirements of, Rule 144A(d)(4) under the Act.

                     (ff)   When the Notes are issued and delivered pursuant
to this Agreement, the Notes will not be of the same class (within the
meaning of Rule 144A under the Act) as any security of the Company that is
listed on a national securities exchange registered under Section 6 of the
Exchange Act or that is quoted in a United States automated inter-dealer
quotation system.

                     (gg)   No form of general solicitation or general
advertising (as defined in Regulation D under the Act) was used by the
Company, or any of its representatives (other than the Initial Purchasers, as
to whom the Company makes no representation) in connection with the offer and
sale of the Notes contemplated hereby, including, but not limited to,
articles, notices or other communications published in any newspaper,
magazine, or similar medium or broadcast over television or radio, or any
seminar or meeting whose attendees have been invited by any general
solicitation or general advertising.  No securities of the same class as the
Securities have been issued and sold by the Company within the six-month
period immediately prior to the date hereof.

                     (hh)   Prior to the effectiveness of any Registration
Statement, the Indenture is not required to be qualified under the TIA.

                     (ii)   No registration under the Act of the Securities
is required for the sale of the Securities to the Initial Purchasers as
contemplated hereby or for the Exempt Resales assuming the accuracy of the
Initial Purchasers' representations and warranties and agreements set forth
in Section 7 hereof.

                     (jj)   Each certificate signed by any officer of the
Company and delivered to the Initial Purchasers or counsel for the Initial
Purchasers pursuant to the terms hereof shall be deemed to be a
representation and warranty by the Company to the Initial Purchasers as to
the matters covered thereby.

                     The Company acknowledges that the Initial Purchasers
and, for purposes of the opinions to be delivered to the Initial Purchasers
pursuant to Section 9 hereof, counsel to the Company and counsel to the
Initial Purchasers will rely upon the accuracy and truth of the foregoing
representations and hereby consents to such reliance.

       7.     INITIAL PURCHASERS' REPRESENTATIONS AND WARRANTIES.  Each
Initial Purchaser, severally and not jointly, represents and warrants to, and
agrees with, the Company:

                                      15

<PAGE>

                     (a)    Such Initial Purchaser is either a QIB or an IAI,
in either case, with such knowledge and experience in financial and business
matters as is necessary in order to evaluate the merits and risks of an
investment in the Notes.

                     (b)    Such Initial Purchaser (A) is not acquiring the
Securities with a view to any distribution thereof or with any present
intention of offering or selling any of the Securities in a transaction that
would violate the Act or the securities laws of any state of the United
States or any other applicable jurisdiction and (B) will be reoffering and
reselling the Securities only to QIBs in reliance on the exemption from the
registration requirements of the Act provided by Rule 144A.

                     (c)    Such Initial Purchaser agrees that no form of
general solicitation or general advertising (within the meaning of Regulation
D under the Act) has been or will be used by such Initial Purchaser or any of
its representatives in connection with the offer and sale of the Securities
pursuant hereto, including, but not limited to, articles, notices or other
communications published in any newspaper, magazine or similar medium or
broadcast over television or radio, or any seminar or meeting whose attendees
have been invited by any general solicitation or general advertising.

                     (d)    Such Initial Purchaser agrees that, in connection
with Exempt Resales, such Initial Purchaser will solicit offers to buy the
Securities only from, and will offer to sell the Securities only to, Eligible
Purchasers.  Each Initial Purchaser further agrees that it will offer to sell
the Securities only to, and will solicit offers to buy the Securities only
from (A) Eligible Purchasers that Such Initial Purchaser reasonably believes
are QIBs that agree that (x) the Securities purchased by them may be resold,
pledged or otherwise transferred within the time period referred to under
Rule 144(k) (taking into account the provisions of Rule 144(d) under the Act,
if applicable) under the Act, as in effect on the date of the transfer of
such Securities, only (I) to the Company or any of its subsidiaries, (II) to
a person whom the seller reasonably believes is a QIB purchasing for its own
account or for the account of a QIB in a transaction meeting the requirements
of Rule 144A under the Act, (III) in an offshore transaction (as defined in
Rule 902 under the Act) meeting the requirements of Rule 904 of the Act, (IV)
in a transaction meeting the requirements of Rule 144 under the Act, (V) to
an Accredited Institution that, prior to such transfer, furnishes the Trustee
a signed letter containing certain representations and agreements relating to
the registration of transfer of such Securities and, if requested by the
Company, an opinion of counsel acceptable to the Company that such transfer
is in compliance with the Act, (VI) in accordance with another exemption from
the registration requirements of the Act (and based upon an opinion of
counsel acceptable to the Company) or (VII) pursuant to an effective
registration statement and, in each case, in accordance with the applicable
securities laws of any state of the United States or any other applicable
jurisdiction and (y) they will deliver to each person to whom such Securities
or an interest therein is transferred a notice substantially to the effect of
the foregoing.

                     (e)    Such Initial Purchaser agrees that it will not
offer, sell or deliver any of the Securities in any jurisdiction outside the
United States except under circumstances that will result in compliance with
the applicable laws thereof, and that it will take at its own expense
whatever action is required to permit its purchase and resale of the
Securities in such jurisdictions.

                                      16

<PAGE>

Such Initial Purchaser understands that no action has been taken to permit a
public offering in any jurisdiction outside the United States where action
would be required for such purpose.

                     Each Initial Purchaser acknowledges that the Company,
for purposes of the opinions to be delivered to each Initial Purchaser
pursuant to Section 9 hereof, counsel to the Company and counsel to the
Initial Purchasers will rely upon the accuracy and truth of the foregoing
representations and each Initial Purchaser hereby consents to such reliance.

       8.     INDEMNIFICATION.

                     (a)    The Company agrees to indemnify and hold harmless
each Initial Purchaser, its directors, its officers and each person, if any,
who controls such Initial Purchaser (within the meaning of Section 15 of the
Act or Section 20 of the Exchange Act), from and against any and all losses,
claims, damages, liabilities and judgments (including, without limitation,
any legal or other expenses incurred in connection with investigating or
defending any matter, including any action, that could give rise to any such
losses, claims, damages, liabilities or judgments) caused by any untrue
statement or alleged untrue statement of a material fact contained in the
Offering Memorandum (or any amendment or supplement thereto), the Preliminary
Offering Memorandum or any Rule 144A Information provided by the Company to
any holder or prospective purchaser of Securities pursuant to Section 5(h) or
caused by any omission or alleged omission to state therein a material fact
required to be stated therein or necessary to make the statements therein not
misleading, except insofar as such losses, claims, damages, liabilities or
judgments are caused by any such untrue statement or omission or alleged
untrue statement or omission based upon information relating to any Initial
Purchaser furnished in writing to the Company by such Initial Purchaser;
provided, however, that the foregoing indemnity agreement with respect to any
Preliminary Offering Memorandum shall not inure to the benefit of any Initial
Purchaser, its directors, its officers and each person, if any, who controls
such Initial Purchaser (within the meaning of Section 15 of the Act or
Section 20 of the Exchange Act), who failed to deliver an Offering Memorandum
(as then amended or supplemented, so long as the Offering Memorandum and any
amendment or supplement thereto was provided by the Company to the several
Initial Purchasers in the requisite quantity and on a timely basis to permit
proper delivery on or prior to the Closing Date) to the person asserting any
losses, claims, damages ad liabilities and judgments caused by any untrue
statement or alleged untrue statement of a material fact contained in any
Preliminary Offering Memorandum, or caused by any omission or alleged
omission to state therein a material fact required to be stated therein or
necessary to make the statements therein not misleading, if such material
misstatement or omission or alleged material misstatement or omission was
cured in the Offering Memorandum.

                     (b)    Each Initial Purchaser, severally and not
jointly, agrees to indemnify and hold harmless the Company and its directors
and officers and each person, if any, who controls (within the meaning of
Section 15 of the Act or Section 20 of the Exchange Act) the Company to the
same extent as the foregoing indemnity from the Company to the Initial
Purchasers but only with reference to information relating to such Initial
Purchaser furnished in writing to the Company by such Initial Purchaser
expressly for use in the Preliminary Offering Memorandum or the Offering
Memorandum.

                                      17

<PAGE>

                     (c)    In case any action shall be commenced involving
any person in respect of which indemnity may be sought pursuant to Section
8(a) or 8(b) (the "INDEMNIFIED PARTY"), the indemnified party shall promptly
notify the person against whom such indemnity may be sought (the
"INDEMNIFYING PARTY") in writing and the indemnifying party shall assume the
defense of such action, including the employment of counsel reasonably
satisfactory to the indemnified party and the payment of all fees and
expenses of such counsel, as incurred (except that in the case of any action
in respect of which indemnity may be sought pursuant to both Sections 8(a)
and 8(b), the Initial Purchasers shall not be required to assume the defense
of such action pursuant to this Section 8(c), but may employ separate counsel
and participate in the defense thereof, but the fees and expenses of such
counsel, except as provided below, shall be at the expense of the Initial
Purchasers).  Any indemnified party shall have the right to employ separate
counsel in any such action and participate in the defense thereof, but the
fees and expenses of such counsel shall be at the expense of the indemnified
party unless (i) the employment of such counsel shall have been specifically
authorized in writing by the indemnifying party, (ii) the indemnifying party
shall have failed to assume the defense of such action or employ counsel
reasonably satisfactory to the indemnified party or (iii) the named parties
to any such action (including any impleaded parties) include both the
indemnified party and the indemnifying party, and the indemnified party shall
have been advised by such counsel that there may be one or more legal
defenses available to it which are different from or additional to those
available to the indemnifying party (in which case the indemnifying party
shall not have the right to assume the defense of such action on behalf of
the indemnified party).  In any such case, the indemnifying party shall not,
in connection with any one action or separate but substantially similar or
related actions in the same jurisdiction arising out of the same general
allegations or circumstances, be liable for the fees and expenses of more
than one separate firm of attorneys (in addition to any local counsel) for
all indemnified parties and all such fees and expeses shall be reimbursed as
they are incurred.  Such firm shall be designated in writing by Donaldson,
Lufkin & Jenrette Securities Corporation, in the case of the parties
indemnified pursuant to Section 8(a), and by the Company, in the case of
parties indemnified pursuant to Section 8(b). The indemnifying party shall
indemnify and hold harmless the indemnified party from and against any and
all losses, claims, damages, liabilities and judgments by reason of any
settlement of any action (i) effected with the indemnifying party's written
consent or (ii) effected without the indemnifying party's written consent if
the settlement is entered into more than twenty business days after the
indemnifying party shall have received a request from the indemnified party
for reimbursement for the fees and expenses of counsel (in any case where
such fees and expenses are at the expense of the indemnifying party) and,
prior to the date of such settlement, the indemnifying party shall have
failed to comply with such reimbursement request.   No indemnifying party
shall, without the prior written consent of the indemnified party, effect any
settlement or compromise of, or consent to the entry of  judgment with
respect to, any pending or threatened action in respect of which the
indemnified party is or could have been a party and indemnity or contribution
may be or could have been sought hereunder by the indemnified party, unless
such settlement, compromise or judgment (i) includes an unconditional release
of the indemnified party from all liability on claims that are or could have
been 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 the indemnified party.

                                      18

<PAGE>

                     (d)    To the extent the indemnification provided for in
this Section 8 is unavailable to an indemnified party or insufficient in
respect of any losses, claims, damages, liabilities or judgments referred to
therein, then each indemnifying party, in lieu of indemnifying such
indemnified party, shall contribute to the amount paid or payable by such
indemnified party as a result of such losses, claims, damages, liabilities
and judgments (i) in such proportion as is appropriate to reflect the
relative benefits received by the Company, on the one hand, and the Initial
Purchasers, on the other hand, from the offering of the Securities or (ii) if
the allocation provided by clause 8(d)(i) above is not permitted by
applicable law, in such proportion as is appropriate to reflect not only the
relative benefits referred to in clause 8(d)(i) above but also the relative
fault of the Company, on the one hand, and the Initial Purchasers, on the
other hand, in connection with the statements or omissions which resulted in
such losses, claims, damages, liabilities or judgments, as well as any other
relevant equitable considerations.  The relative benefits received by the
Company, on the one hand, and the Initial Purchasers, on the other hand,
shall be deemed to be in the same proportion as the total net proceeds from
the offering of the Securities (after Initial Purchaser's discounts or
commissions, but before deducting expenses) received by the Company, and the
total discounts and commissions received by the Initial Purchasers bear to
the total price to investors of the Securities, in each case as set forth in
the table on the cover page of the Offering Memorandum.  The relative fault
of the Company, on the one hand, and the Initial Purchasers, on the other
hand, 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 the Initial Purchasers, on the other hand,
and the parties' relative intent, knowledge, access to information and
opportunity to correct or prevent such statement or omission.

                     The Company and the Initial Purchasers agree that it
would not be just and equitable if contribution pursuant to this Section 8(d)
were determined by pro rata allocation (even if the Initial Purchasers were
treated as one entity for such purpose) or by any other method of allocation
which does not take account of the equitable considerations referred to in
the immediately preceding paragraph.  The amount paid or payable by an
indemnified party as a result of the losses, claims, damages, liabilities or
judgments referred to in the immediately preceding paragraph shall be deemed
to include, subject to the limitations set forth above, any legal or other
expenses incurred by such indemnified party in connection with investigating
or defending any matter, including any action, that could have given rise to
such losses, claims, damages, liabilities or judgments.  Notwithstanding the
provisions of this Section 8, no Initial Purchaser shall be required to
contribute any amount in excess of the amount by which the total discounts
and commissions received by such Initial Purchaser exceeds the amount of any
damages which such Initial Purchaser has 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.  The
Initial Purchasers' obligations to contribute pursuant to this Section 8(d)
are several in proportion to the respective principal amount of Securities
purchased by each of the Initial Purchasers hereunder, and not joint.

                     (e)    The remedies provided for in this Section 8 are
not exclusive and shall not limit any rights or remedies which may otherwise
be available to any indemnified party at law or in equity.

                                      19

<PAGE>

       9.     CONDITIONS OF INITIAL PURCHASER'S OBLIGATIONS.  The several
obligations of the Initial Purchasers to purchase the Firm Notes under this
Agreement on the Closing Date and the Additional Notes, if any, on any Option
Closing Date are subject to the satisfaction of each of the following
conditions.

                     (a)    All the representations and warranties of the
Company contained in this Agreement shall be true and correct on the Closing
Date, or on each Option Closing Date, if any, with the same force and effect
as if made on and as of the Closing Date or on each Option Closing Date, if
any.

                     (b)    On or after the date hereof, (i) there shall not
have occurred any downgrading, suspension or withdrawal of, nor shall any
notice have been given of any potential or intended downgrading, suspension
or withdrawal of, or of any review (or of any potential or intended review)
for a possible change that does not indicate the direction of the possible
change in, any rating of the Company or any securities of the Company
(including, without limitation, the placing of any of the foregoing ratings
on credit watch with negative or developing implications or under review with
an uncertain direction) by any "nationally recognized statistical rating
organization" as such term is defined for purposes of Rule 436(g)(2) under
the Act, (ii) there shall not have occurred any change, nor shall any notice
have been given of any potential or intended change, in the outlook for any
rating of the Company or any securities of the Company by any such rating
organization and (iii) no such rating organization shall have given notice
that it has assigned (or is considering assigning) a lower rating to the
Notes than that on which the Notes were marketed.

                     (c)    Since the respective dates as of which
information is given in the Offering Memorandum other than as set forth in
the Offering Memorandum (exclusive of any amendments or supplements thereto
subsequent to the date of this Agreement), (i) there shall not have occurred
any change or any development involving a prospective change in the
condition, financial or otherwise, or the earnings, business, management or
operations of the Company and its subsidiaries, taken as a whole, (ii) there
shall not have been any change or any development involving a prospective
change in the capital stock or in the long-term debt of the Company or any of
its subsidiaries and (iii) neither the Company nor any of its subsidiaries
shall have incurred any liability or obligation, direct or contingent, the
effect of which, in any such case described in clause 9(c)(i), 9(c)(ii) or
9(c)(iii), in your judgment, is material and adverse and, in your judgment,
makes it impracticable to market the Securities on the terms and in the
manner contemplated in the Offering Memorandum.

                     (d)    You shall have received on the Closing Date a
certificate, dated the Closing Date, and on an Option Closing Date, if any,
dated such Option Closing Date, signed by Lyle C. Turner and James R. Glynn,
in their capacities as President and Chief Executive Officer, and Executive
Vice President and Chief Financial Officer, respectively, of the Company,
confirming the matters set forth in Sections 6(dd), 9(a) and 9(b) and stating
that the Company has complied with all the agreements and satisfied all of
the conditions herein contained and required to be complied with or satisfied
on or prior to the Closing Date or Option Closing Date, as the case may be.

                                      20

<PAGE>

                     (e)    You shall have received on the Closing Date and
each Option Closing Date, if any, an opinion (satisfactory to you and counsel
for the Initial Purchasers), dated the Closing Date or such Option Closing
Date, as the case may be, of Gray Cary Ware & Freidenrich LLP, counsel for
the Company, or of foreign counsel to the Company with respect to certain
foreign subsidiaries, to the effect that:

                            (i)    each of the Company and its subsidiaries has
       been duly incorporated, is validly existing as a corporation in good
       standing under the laws of its jurisdiction of incorporation and has the
       corporate power and authority to carry on its business as described in
       the Offering Memorandum and to own, lease and operate its properties.

                            (ii)   each of the Company and its subsidiaries is
       duly qualified and is in good standing as a foreign corporation
       authorized to do business in each jurisdiction in which the nature of its
       business or its ownership or leasing of property requires such
       qualification, except where the failure to be so qualified would not have
       a material adverse effect on the business, prospects, financial condition
       or results of operations of the Company and its subsidiaries, taken as a
       whole;

                            (iii)  all of the outstanding shares of capital
       stock of each of the Company's subsidiaries have been duly authorized and
       validly issued and are fully paid and non-assessable and, to such
       counsel's knowledge, are owned of record by the Company, free and clear
       of any Lien;

                            (iv)   the Notes have been duly authorized and, when
       executed and authenticated in accordance with the provisions of the
       Indenture and delivered to and paid for by the Initial Purchasers in
       accordance with the terms of this Agreement, will be entitled to the
       benefits of the Indenture and will be valid and binding obligations of
       the Company, enforceable in accordance with their terms except as (x) the
       enforceability thereof may be limited by bankruptcy, insolvency or
       similar laws affecting creditors' rights generally and (y) rights of
       acceleration and availability of equitable remedies may be limited by
       equitable principles of general applicability;

                            (v)    the Indenture has been duly authorized,
       executed and delivered by the Company and is a valid and binding
       agreement of the Company, enforceable against the Company in accordance
       with its terms except as (x) the enforceability thereof may be limited by
       bankruptcy, insolvency or similar laws affecting creditors' rights
       generally and (y) rights of acceleration and the availability of
       equitable remedies may be limited by equitable principles of general
       applicability;

                            (vi)   the Notes are convertible into Common Stock
       in accordance with the terms of the Indenture; the shares of Common Stock
       initially issuable upon conversion of the Notes have been duly authorized
       and reserved for issuance upon such conversion and, when issued upon such
       conversion, will be validly issued, fully paid and nonassessable, will
       conform to the description thereof contained in the Offering Memorandum
       and will be duly authorized for listing on the NASDAQ National Market,

                                      21

<PAGE>

       subject to notice of official issuance; the Company has the authorized
       capital stock as set forth in the Offering Memorandum; and the
       stockholders of the Company have no pre-emptive or, to the knowledge of
       such counsel, similar rights with respect to the Notes or the Common
       Stock issuable upon the conversion of the Notes;

                            (vii)  this Agreement has been duly authorized,
       executed and delivered by the Company;

                            (viii) The Registration Rights Agreement has been
       duly authorized, executed and delivered by the Company and is a valid and
       binding agreement of the Company enforceable against the Company in
       accordance with its terms, except as (x) the enforceability thereof may
       be limited by bankruptcy, insolvency or similar laws affecting creditors'
       rights generally and (y) rights of acceleration and the availability of
       equitable remedies may be limited by equitable principles of general
       applicability;

                            (ix)   the statements under the captions
       "Business Technology Licensing", "Business Patents and Proprietary
       Technologies", "Management Limitations on Liability and Indemnification
       Matters," "Management Stock Option Plans", "Management Employee Stock
       Ownership Plan", "Management 1998 Employee Stock Purchase Plan",
       "Management Section 401(k) Plan," "Description of Notes," "Description of
       Capital Stock" and "Summary of Certain Federal Income Tax Considerations"
       in the Offering Memorandum, insofar as such statements constitute a
       summary of the legal matters, documents or proceedings referred to
       therein, fairly present in all material respects such legal matters,
       documents and proceedings;

                            (x)    to such counsel's knowledge, except as set
       forth in Exhibit A to such counsel's opinion, neither the Company nor any
       of its subsidiaries is in violation of its respective charter or by-laws
       and neither the Company nor any of its subsidiaries is in default in the
       performance of any obligation, agreement, covenant or condition contained
       in any indenture, loan agreement, mortgage, lease or other agreement or
       instrument that is material to the Company and its subsidiaries, taken as
       a whole, to which the Company or any of its subsidiaries is a party or by
       which the Company or any of its subsidiaries or their respective property
       is bound;

                            (xi)   the execution, delivery and performance of
       this Agreement and the other Operative Documents by the Company, the
       compliance by the Company with all provisions hereof and thereof and the
       consummation of the transactions contemplated hereby and thereby will not
       (i) require any consent, approval, Material Authorization or other order
       of, or qualification with, any court or governmental body or agency
       (except such as may be required under the securities or Blue Sky laws of
       the various states or for filings required by the Registration Rights
       Agreement), (ii) conflict with or constitute a breach of any of the terms
       or provisions of, or a default under, the charter or by-laws of the
       Company or any of its subsidiaries or any indenture, loan agreement,
       mortgage, lease or other agreement or instrument to which the Company or
       any of its subsidiaries is a party or by which the Company or any of its
       subsidiaries or their respective property is bound and that is material
       to the Company and its subsidiaries, taken as a whole, (iii) violate or
       conflict

                                      22

<PAGE>

       with any applicable law or any rule or regulation, or, to such
       counsel's knowledge, any judgment, order or decree of any court or any
       governmental body or agency having jurisdiction over the Company, any of
       its subsidiaries or their respective property, (iv) result in the
       imposition or creation of (or the obligation to create or impose) a Lien
       under, any agreement or instrument to which the Company or any of its
       subsidiaries is a party or by which the Company or any of its
       subsidiaries or their respective property is bound, or (v) to such
       counsel's knowledge, result in the termination, suspension or revocation
       of any Material Authorization of the Company or any of its subsidiaries;

                            (xii)  except as set forth on Exhibit B to such
       counsel's opinion or in the Offering Memorandum, such counsel does not
       know of any legal or governmental proceedings pending or threatened to
       which the Company or any of its subsidiaries is or could be a party or to
       which any of their respective property is or could be subject, which
       might result, singly or in the aggregate, in a material adverse effect on
       the business, prospects, financial condition or results of operations of
       the Company and its subsidiaries, taken as a whole;

                            (xiii) the Company is not and, after giving effect
       to the offering and sale of the Notes and the application of the net
       proceeds thereof as described in the Offering Memorandum, will not be, an
       "investment company" as such term is defined in the Investment Company
       Act of 1940, as amended;

                            (xiv)  except as set forth in the Offering
       Memorandum, to such counsel's knowledge, there are no contracts,
       agreements or understandings between the Company and any person granting
       such person the right to require the Company to file a registration
       statement under the Act with respect to any securities of the Company or
       to require the Company to include such securities with the Notes
       registered pursuant to any Registration Statement;

                            (xv)   to such counsel's knowledge, neither the
       Company nor any of its subsidiaries has received any notice of
       infringement of or conflict with asserted rights of others with respect
       to any of the Company's patent rights, licenses, copyrights, know-how
       (including trade secrets and other unpatented and/or unpatentable
       proprietary or confidential information, systems or procedures),
       trademarks, service marks and trade names which has not been resolved and
       which, singly or in the aggregate, might result in a material adverse
       effect on the business, prospects, financial condition or results of
       operations of the Company and its subsidiaries, taken as a whole;

                            (xvi)  the Indenture complies as to form in all
       material respects with the requirements of the TIA, and the rules and
       regulations of the Commission applicable to an indenture which is
       qualified thereunder.  It is not necessary in connection with the offer,
       sale and delivery of the Notes to the Initial Purchasers in the manner
       contemplated by this Agreement or in connection with the Exempt Resales
       to qualify the Indenture under the TIA; and

                                      23

<PAGE>

                            (xvii) no registration under the Act of the
       Securities is required for the sale of the Securities to the Initial
       Purchasers as contemplated by this Agreement or for the Exempt Resales
       assuming that (i) each Initial Purchaser is a QIB, (ii) the accuracy of,
       and compliance with, the Initial Purchasers' representations and
       agreements contained in Section 7 of this Agreement, (iii) the accuracy
       of the representations of the Company set forth in Sections 5(h) and 6(z)
       of this Agreement.

                     Such opinion shall also include a statement that such
counsel has no reason to believe that, as of the date of the Offering
Memorandum or as of the Closing Date or the Option Closing Date, as the case
may be, the Offering Memorandum, as amended or supplemented, if applicable
(except for the financial statements and other financial data included
therein, as to which such counsel need not express any belief) contains any
untrue statement of a material fact or omits to state a material fact
necessary in order to make the statements therein, in the light of the
circumstances under which they were made, not misleading.

                     The opinion of Gray Cary Ware Freidenrich LLP and of the
foreign counsel to the Company described in Section 9(e) above shall be
rendered to you at the request of the Company and shall so state therein.  In
giving such statement, Gray Cary Ware Freidenrich LLP may state that their
opinion and belief are based upon their participation in the preparation of
the Offering Memorandum and any amendments or supplements thereto and review
and discussion of the contents thereof, but are without independent check or
verification except as specified.

                     (f)    The Initial Purchasers shall have received on the
Closing Date and on each Option Closing Date, an opinion, dated the Closing
Date, of Latham & Watkins, counsel for the Initial Purchasers, in form and
substance reasonably satisfactory to the Initial Purchasers.

                     (g)    The Initial Purchasers shall have received, at
the time this Agreement is executed and at the Closing Date and each Option
Closing Date, letters dated the date hereof or the Closing Date or an Option
Closing Date, as the case may be, in the form and substance satisfactory to
the Initial Purchasers from Arthur Andersen LLP, independent public
accountants, containing the information and statements of the type ordinarily
included in accountants' "comfort letters" to the Initial Purchasers with
respect to the financial statements and certain financial information
contained in the Offering Memorandum.

                     (h)    The Notes shall have been approved by the NASD
for trading and duly listed in PORTAL.

                     (i)    The Initial Purchasers shall have received a
counterpart, conformed as executed, of the Indenture which shall have been
entered into by the Company and the Trustee.

                     (j)    The Company shall have executed the Registration
Rights Agreement and the Initial Purchasers shall have received an original
copy thereof, duly executed by the Company.

                     (k)    The Company shall not have failed at or prior to
the Closing Date or any Option Closing Date, as the case may be, to perform
or comply with any of the agreements

                                      24

<PAGE>

herein contained and required to be performed or complied with by the Company
at or prior to the Closing Date or  Option Closing Date, as the case may be.

       10.    EFFECTIVENESS OF AGREEMENT AND TERMINATION. This Agreement may
be terminated at any time on or prior to the Closing Date by the Initial
Purchasers by written notice to the Company if any of the following has
occurred:  (i) any outbreak or escalation of hostilities or other national or
international calamity or crisis or change in economic conditions or in the
financial markets of the United States or elsewhere that, in the Initial
Purchasers' judgment, is material and adverse and, in the Initial Purchasers'
judgment, makes it impracticable to market the Securities on the terms and in
the manner contemplated in the Offering Memorandum, (ii) the suspension or
material limitation of trading in securities or other instruments on the New
York Stock Exchange, the American Stock Exchange, the Chicago Board of
Options Exchange, the Chicago Mercantile Exchange, the Chicago Board of Trade
or the Nasdaq National Market or limitation on prices for securities or other
instruments on any such exchange or the Nasdaq National Market, (iii) the
suspension of trading of any securities of the Company on any exchange or in
the over-the-counter market, (iv) the enactment, publication, decree or other
promulgation of any federal or state statute, regulation, rule or order of
any court or other governmental authority which in your opinion materially
and adversely affects, or will materially and adversely affect, the business,
prospects, financial condition or results of operations of the Company and
its subsidiaries, taken as a whole, (v) the declaration of a banking
moratorium by either federal or New York State authorities or (vi) the taking
of any action by any federal, state or local government or agency in respect
of its monetary or fiscal affairs which in your opinion has a material
adverse effect on the financial markets in the United States.

       If on the Closing Date or an Option Closing Date, as the case may be,
any one or more of the Initial Purchasers shall fail or refuse to purchase
the Notes which it or they have agreed to purchase hereunder on such date and
the aggregate principal amount of the Notes which such defaulting Initial
Purchaser or Initial Purchasers, as the case may be, agreed but failed or
refused to purchase is not more than one-tenth of the aggregate principal
amount of the Notes to be purchased on such date by all Initial Purchasers,
each non-defaulting Initial Purchaser shall be obligated severally, in the
proportion which the principal amount of the Notes set forth opposite its
name in Schedule A bears to the aggregate principal amount of the Notes which
all the non-defaulting Initial Purchasers, as the case may be, have agreed to
purchase, or in such other proportion as you may specify, to purchase the
Notes which such defaulting Initial Purchaser or Initial Purchasers, as the
case may be, agreed but failed or refused to purchase on such date; PROVIDED
that in no event shall the aggregate principal amount of the Notes which any
Initial Purchaser has agreed to purchase pursuant to Section 2 hereof be
increased pursuant to this Section 10 by an amount in excess of one-tenth of
such principal amount of the Notes without the written consent of such
Initial Purchaser.  If on the Closing Date, or an Option Closing Date, as the
case may be, any Initial Purchaser or Initial Purchasers shall fail or refuse
to purchase the Notes and the aggregate principal amount of the Notes with
respect to which such default occurs is more than one-tenth of the aggregate
principal amount of the Notes to be purchased by all Initial Purchasers and
arrangements satisfactory to the Initial Purchasers and the Company for
purchase of such the Notes are not made within 48 hours after such default,
this Agreement will terminate without liability on the part of any
non-defaulting Initial Purchaser and the Company.  In any such case which
does not result in termination of this Agreement, either you or the Company
shall have the right to postpone the

                                      25

<PAGE>

Closing Date, or such Option Closing Date, as the case may be, but in no
event for longer than seven days, in order that the required changes, if any,
in the Offering Memorandum or any other documents or arrangements may be
effected.  Any action taken under this paragraph shall not relieve any
defaulting Initial Purchaser from liability in respect of any default of any
such Initial Purchaser under this Agreement.

       11.    MISCELLANEOUS.  Notices given pursuant to any provision of this
Agreement shall be addressed as follows:  (i) if to the Company to Invitrogen
Corporation, 1600 Faraday Avenue, Carlsbad, California, 92008, and (ii) if to
the Initial Purchasers, Donaldson, Lufkin & Jenrette Securities Corporation,
277 Park Avenue, New York, New York 10172, Attention:  Syndicate Department,
or in any case to such other address as the person to be notified may have
requested in writing

       The respective indemnities, contribution agreements, representations,
warranties and other statements of the Company and the Initial Purchasers set
forth in or made pursuant to this Agreement shall remain operative and in
full force and effect, and will survive delivery of and payment for the
Securities regardless of (i) any investigation, or statement as to the
results thereof, made by or on behalf of the Initial Purchasers; the officers
or directors of the Initial Purchasers, any person controlling the Initial
Purchasers, the Company, the officers or directors of the Company, or any
person controlling the Company, (ii) acceptance of the Securities and payment
for them hereunder and (iii) termination of the Agreement.

       If for any reason the Notes are not delivered by or on behalf of the
Company as provided herein (other than as a result of any termination of this
Agreement pursuant to Section 10), the Company agrees to reimburse the
Initial Purchasers for all out-of-pocket expenses (including the fees and
disbursements of counsel) incurred by them  Notwithstanding any termination
of this Agreement, the Company shall be liable for all expenses which it has
agreed to pay pursuant to section 5(i) hereof.  The Company also agrees to
reimburse the Initial Purchasers and its officers, directors and each person,
if any, who controls such Initial Purchasers within the meaning of Section 15
of the Act or Section 20 of the Exchange Act for any and all fees and
expenses (including without limitation the fees and expenses of counsel)
incurred by them in connection with enforcing their rights under this
Agreement (including without limitation its rights under Section 8).

       Except as otherwise provided, this Agreement has been and is made
solely for the benefit of and shall be binding upon the Company, the Initial
Purchasers, the Initial Purchasers' directors and officers, any controlling
persons referred to herein, the directors of the Company and their respective
successors and assigns, all as and to the extent provided in this Agreement,
and no other person shall acquire or have any right under or by virtue of
this Agreement.  The term "successors and assigns" shall not include a
purchaser of any of the Securities from the Initial Purchasers merely because
of such purchase.

       This Agreement shall be governed and construed in accordance with the
laws of the State of New York.

       This Agreement may be signed in various counterparts which together
shall constitute one and the same instrument.

                                      26

<PAGE>

       Please confirm that the foregoing correctly sets forth the agreement
among the Company, and the Initial Purchasers.

                                Very truly yours,

                                INVITROGEN CORPORATION

                                By:       /s/ Lyle C. Turner
                                   ----------------------------------
                                   Name:  Lyle C. Turner
                                   Title: President and Chief Executive Officer

DONALDSON, LUFKIN & JENRETTE
SECURITIES CORPORATION
BEAR, STEARNS & CO. INC.
CHASE SECURITIES INC.
DAIN RAUSCHER INCORPORATED
U.S. BANCORP PIPER JAFFRAY INC.
By:    DONALDSON, LUFKIN & JENRETTE
             SECURITIES CORPORATION

By:    /s/ Edward M. Brown
   --------------------------
   Name:  Edward M. Brown
   Title: Managing Director

                                      27

<PAGE>

                                   SCHEDULE A

<TABLE>
<CAPTION>
                                                            Principal Amount
Initial Purchaser                                               of Notes
-----------------                                        -----------------------
<S>                                                     <C>
Donaldson, Lufkin & Jenrette
     Securities Corporation........................            $105,000,000
Bear, Stearns & Co. Inc............................              11,250,000
Chase Securities Inc...............................              11,250,000
Dain Rauscher Incorporated.........................              11,250,000
U.S. Bancorp Piper Jaffray Inc.....................              11,250,000
          Total....................................            $150,000,000
                                                               ============

</TABLE>
                                      28

<PAGE>

                                     SCHEDULE B

                                    SUBSIDIARIES

Invitrogen Export Company, Ltd.

Invitrogen B.V.

NOVEX

NOVEX International Sales Corporation

NOVEX Electrophoresis GmbH

Serva GmbH

Research Genetics, Inc.

                                      29

<PAGE>

                                     EXHIBIT A

                       FORM OF REGISTRATION RIGHTS AGREEMENT

                                      30

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