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                                                                    EXHIBIT 10.6

                                     MITOKOR

                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

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                                 August 24, 2000

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                                TABLE OF CONTENTS

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1.       Authorization and Sale of Preferred Shares...............................................................1
         1.1      Authorization; Amended and Restated Articles of Incorporation...................................1
         1.2      Sale and Issuance of the Preferred Shares.......................................................1

2.       Closing Date; Delivery...................................................................................1
         2.1      Closing Dates...................................................................................1
         2.2      Delivery........................................................................................2

3.       Representations and Warranties of the Company............................................................2
         3.1      Organization and Standing; Articles and By-Laws.................................................2
         3.2      Corporate Power.................................................................................2
         3.3      Subsidiaries....................................................................................2
         3.4      Capitalization..................................................................................2
         3.5      Authorization...................................................................................3
         3.6      Patents and Other Proprietary Rights............................................................4
         3.7      Compliance with Other Instruments, None Burdensome, etc.........................................5
         3.8      Proprietary Agreements; Employees...............................................................5
         3.9      Condition of Properties.........................................................................5
         3.10     Litigation, etc.................................................................................6
         3.11     Governmental Consent, etc.......................................................................6
         3.12     Offering........................................................................................6
         3.13     Taxes...........................................................................................6
         3.14     Title...........................................................................................7
         3.15     Material Contracts and Commitments..............................................................7
         3.16     Financial Statements............................................................................7
         3.17     Absence of Changes..............................................................................7
         3.18     Outstanding Indebtedness........................................................................8
         3.19     Registration Rights.............................................................................8
         3.20     Certain Transactions............................................................................8
         3.21     Corporate Documents; Minute Books...............................................................9
         3.22     Employee Benefit Plans..........................................................................9
         3.23     Labor Agreements................................................................................9
         3.24     Real Property Holding Corporation...............................................................9
         3.25     Disclosure......................................................................................9
         3.26     Insurance.......................................................................................9
         3.27     Shareholder Agreements..........................................................................9
         3.28     Environmental Matters..........................................................................10
         3.29     Manufacturing Rights...........................................................................10
         3.30     Assumptions, Guaranties, Etc. of Indebtedness of Other Persons.................................10
         3.31     Material Customers and Suppliers...............................................................11

4.       Representations and Warranties of Purchaser and Restrictions on Transfer Imposed by the
         Securities Act..........................................................................................11
         4.1      Representations and Warranties by the Purchaser................................................11
         4.2      Legends........................................................................................12

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                               TABLE OF CONTENTS
                                  (continued)

         4.3      Removal of Legend and Transfer Restrictions....................................................13
         4.4      Rule 144.......................................................................................13

5.       Conditions to Closing...................................................................................13
         5.1      Conditions to Purchasers' Obligations..........................................................13
         5.2      Conditions to Obligations of the Company.......................................................14

6.       Affirmative Covenants of the Company....................................................................14
         6.1      Financial Information..........................................................................14
         6.2      Conflicts of Interests.........................................................................15
         6.3      Key Man Insurance..............................................................................15
         6.4      Proprietary Agreements.........................................................................15
         6.5      Future Stock Issuances.........................................................................15
         6.6      Rule 144.......................................................................................16
         6.7      Transactions with Affiliates...................................................................16
         6.8      Inspection Rights..............................................................................16

7.       Miscellaneous...........................................................................................16
         7.1      Waivers and Amendments.........................................................................16
         7.2      Governing Law..................................................................................17
         7.3      Survival.......................................................................................17
         7.4      Successors and Assigns.........................................................................17
         7.5      Entire Agreement...............................................................................17
         7.6      Notices, etc...................................................................................17
         7.7      Severability...................................................................................17
         7.8      Titles and Subtitles...........................................................................17
         7.9      Counterparts...................................................................................17
         7.10     Delays or Omissions............................................................................18
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                                LIST OF EXHIBITS

EXHIBIT A - Amended and Restated Articles of Incorporation

EXHIBIT B - Schedule of Exceptions

EXHIBIT C - Investors' Rights Agreement

EXHIBIT D - Shareholders of the Company

EXHIBIT E - Holders of Outstanding Options and Warrants of the Company

EXHIBIT F - Patents and Trademarks

EXHIBIT G - Material Contracts

EXHIBIT H - Financial Statements

EXHIBIT I - Opinion of Counsel for the Company

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                                     MITOKOR

                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

         THIS AGREEMENT is made as of August 24, 2000, by and among MITOKOR, a
California corporation (the "Company"), and the individuals and entities listed
on the Schedule of Purchasers attached hereto (the "Purchasers"). The parties
hereby agree as follows:

         1. AUTHORIZATION AND SALE OF PREFERRED SHARES.

                  1.1 AUTHORIZATION; AMENDED AND RESTATED ARTICLES OF
INCORPORATION. The Company has authorized the issuance and sale to the
Purchaser, pursuant to the terms and conditions hereof, of up to 4,000,000
shares of its Series F Preferred Stock (the "Preferred Shares") at a purchase
price of $7.50 per share. The Preferred Shares have the rights, preferences
and provisions as set forth in the Company's Amended and Restated Articles of
Incorporation (the "Articles") attached hereto as EXHIBIT A.

                  1.2 SALE AND ISSUANCE OF THE PREFERRED SHARES. Subject to
the terms and conditions hereof, the Company will issue and sell to Purchaser
and Purchaser will purchase the Preferred Shares at the purchase price per
Preferred Share as indicated in Section 1.1.

         2. CLOSING DATE; DELIVERY.

                  2.1 CLOSING DATES.

                           (a)      FIRST CLOSING.  The closing of the purchase
and sale of at least 1,600,000 of the Preferred Shares shall be held at the
offices of Gray Cary Ware & Freidenrich, 4365 Executive Drive, Suite 1600, San
Diego, California 92121-2189, at 10:00 a.m. on August 24, 2000, or at such other
time and place as the Company and the Purchaser may mutually agree upon orally
or in writing (which time and place are designated as the "First Closing").

                           (b)      SECOND CLOSING.  The closing of the purchase
and sale of up to the remaining Preferred Shares (the "Second Closing") shall
take place at the offices of Gray Cary Ware & Freidenrich within 120 days of the
First Closing and shall be subject to the terms and conditions of this Agreement
and Exhibits attached hereto.

                           (c)      DEFINITIONS.  The First Closing  and the
Second Closing are sometimes referred to hereinafter as the "Closings" or
individually as a "Closing". The date of the First Closing is hereinafter
referred to as the "First Closing Date" and the date of the Second Closing is
referred to hereinafter as the "Second Closing Date"; and the First Closing Date
and the Second Closing Date are hereinafter referred to collectively as the
"Closing Dates" or individually as a "Closing Date".

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                  2.2 DELIVERY. Subject to the terms of this Agreement, at the
Closings the Company will deliver to Purchaser a certificate representing the
Preferred Shares to be purchased by Purchaser from the Company, against payment
of the purchase price therefor by a check or wire transfer made payable to the
order of the Company.

         3. REPRESENTATIONS AND WARRANTIES OF THE COMPANY. The Company hereby
represents and warrants to the Purchaser that except as set forth on the
Schedule of Exceptions attached hereto as EXHIBIT B, which exceptions shall be
deemed to be representations and warranties as if made hereunder:

                  3.1 ORGANIZATION AND STANDING; ARTICLES AND BY-LAWS. The
Company is a corporation duly organized, validly existing and in good standing
under the laws of the State of California and has all requisite corporate power
and authority to carry on its businesses as now conducted and as proposed to be
conducted. The Company is qualified or licensed to do business as a foreign
corporation in all jurisdictions where such qualification or licensing is
required, except where the failure to so qualify would not have a material
adverse effect upon the Company. Copies of the Company's Articles of
Incorporation, Bylaws, minutes and consents of shareholders and of the Board of
Directors are available for inspection at the Company's offices or have been
previously provided to the Purchaser.

                  3.2 CORPORATE POWER. The Company has now, or will have at the
Closing Dates, all requisite corporate power to enter into this Agreement and
the Investors' Rights Agreement (the "Rights Agreement") in substantially the
form attached hereto as EXHIBIT C and to sell and issue the Preferred Shares and
to issue the Common Stock upon conversion of the Preferred Shares. This
Agreement and the Rights Agreement are valid and binding obligations of the
Company enforceable in accordance with their respective terms, except as the
same may be limited by bankruptcy, insolvency, moratorium, and other laws of
general application affecting the enforcement of creditors' rights.

                  3.3 SUBSIDIARIES.  The Company does not control, directly or
indirectly, any other corporation, association or business entity.

                  3.4 CAPITALIZATION. The authorized capital stock of the
Company is 18,000,000 shares of Common Stock, of which 190,442 shares are issued
and outstanding and 18,000,000 shares of Preferred Stock issuable in series, of
which (i) 52,000 shares are designated Series A-1 Preferred Stock, 52,000 shares
of which are issued and outstanding; (ii)7,200 shares are designated Series B
Preferred Stock, 7,200 shares of which are issued and outstanding; (iii) 90,000
shares are designated Series B-1 Preferred Stock, 90,000 of which are issued and
outstanding; (iv) 30,000 shares are designated Series B-2 Preferred Stock,
30,000 of which are issued and outstanding; (v) 30,000 shares are designated
Series B-3 Preferred Stock, 30,000 of which are issued and outstanding; (vi)
3,600 shares are designated Series B-4 Preferred Stock, 3,600 of which are
issued and outstanding; (vii) 3,308,431 shares are designated Series C Preferred
Stock, 3,292,431 of which are issued and outstanding; (viii) 3,358,042 shares
are designated Series D Preferred Stock, 3,351,042 of which are issued and
outstanding; (ix) 3,358,042 shares are designated Series D-1 Preferred Stock,
none of which are issued and outstanding; (x) 853,167 shares are designated
Series E Preferred Shares, 833,334 of which are issued and outstanding; and (xi)
4,000,000 shares are designated Series F Preferred Shares, none of which are
issued and outstanding. The holders of record of the presently issued and

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outstanding Common Stock and Preferred Stock immediately prior to the Closings
are as set forth on EXHIBIT D. All such issued and outstanding shares have been
duly authorized and validly issued, are fully paid and nonassessable, and were
issued in compliance with all applicable state and federal laws concerning the
issuance of securities. The Company has reserved 113,043 shares of Common Stock
for issuance upon the conversion of Series A-1 Preferred Stock, 574,285 shares
of Common Stock for issuance upon the conversion of Series B Preferred Stock,
Series B-1 Preferred Stock, Series B-2 Preferred Stock, Series B-3 Preferred
Stock and Series B-4 Preferred Stock, 3,308,431 shares of Common Stock for
issuance upon the conversion of Series C Preferred Stock, 3,358,042 shares of
Common Stock for issuance upon the conversion of Series D Preferred Stock,
3,358,042 shares of Common Stock for issuance upon the conversion of Series D-1
Preferred Stock, 853,167 shares of Common Stock for issuance upon the conversion
of Series E Preferred Stock, 4,000,000 shares of Common Stock for issuance upon
the conversion of Series F Preferred Stock, 67,042 shares of Common Stock for
issuance pursuant to the exercise of outstanding Common Stock purchase warrants,
16,000 shares of Series C Preferred Stock for issuance pursuant to the exercise
of Series C Preferred Stock purchase warrants, 7,000 shares of Series D
Preferred Stock for issuance pursuant to the exercise of Series D Preferred
Stock purchase warrants, 19,833 shares of Series E Preferred Stock for issuance
pursuant to the exercise of Series E Preferred Stock purchase warrants,
1,987,318 shares of Common Stock for issuance to employees, directors, and
consultants pursuant to its Amended and Restated 1993 Stock Option Plan and
2,480 shares of Common Stock for issuance upon exercise of nonstatutory options
granted by the Company in 1991 and 1992. The holders of any and all rights,
warrants or conversion rights to purchase or acquire from the Company any of its
capital stock, along with the number of shares of capital stock issuable upon
exercise of such rights, are set forth on EXHIBIT E attached hereto. Except for
such rights, there are no outstanding rights, warrants, conversion rights or
agreements for the purchase or acquisition from the Company of any shares of its
capital stock. The rights, privileges and preferences of the Series E Preferred
Stock are as set forth in the Articles attached hereto as EXHIBIT A.

                  3.5  AUTHORIZATION.

                           (a)      CORPORATE ACTION.  All corporate action on
the part of the Company, its officers, directors and shareholders necessary for
the sale and issuance of the Preferred Shares and the issuance of the Common
Stock issuable upon conversion of the Preferred Shares and the performance of
the Company's obligations hereunder and under the Rights Agreement has been
taken or will be taken prior to the Closings. The Company has duly reserved an
aggregate of 4,000,000 shares of Common Stock for issuance upon conversion of
the Preferred Shares.

                           (b)      VALID ISSUANCE.  The Preferred Shares, when
issued in compliance with the provisions of this Agreement and the shares of
Common Stock issuable upon conversion of the Preferred Shares when issued in
accordance with the provisions of the Articles, will be duly authorized, validly
issued, fully paid and nonassessable and will be free of any liens or
encumbrances caused or created by the Company; provided, however, that all such
shares may be subject to restrictions on transfer under state and/or federal
securities laws as set forth herein, and as may be required by future changes in
such laws. The rights, preferences, privileges and restrictions of the Preferred
Shares are as set forth in the Articles.

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                           (c)      NO PREEMPTIVE RIGHTS.  Except as set forth
in the Rights Agreement, no person has any right of first refusal or any
preemptive rights in connection with the issuance of the Preferred Shares, the
issuance of the Common Stock upon conversion of the Preferred Shares or any
future issuances of securities by the Company.

                  3.6 PATENTS AND OTHER PROPRIETARY RIGHTS. EXHIBIT F attached
hereto contains a full and complete list of all patents and patent applications,
trademarks and trademark applications, trade names, service marks and service
mark applications and copyrights owned or used by the Company or in which it has
any rights or licenses. The Company has entered into agreements with each of its
officers, employees and consultants providing the Company, to the extent
permitted by law, with title and ownership to patents, patent applications,
trade secrets and inventions conceived, developed, reduced to practice by or at
the direction of such person, solely or jointly, during the period of employment
by the Company. Except as described in EXHIBIT F:

                           (a)      The Company owns or possesses adequate
licenses or other rights (or is able to obtain adequate licenses, rights or
purchase options on terms that will not materially and adversely affect its
business) to use all patents, patent applications, trademarks, trademark
applications, trade secrets, service marks, service mark applications, trade
names, copyrights, inventions, drawings, designs, customer lists, proprietary
know-how or information, or other rights with respect thereto (collectively
referred to as "MitoKor Proprietary Rights"), used in the business of the
Company, and the same are sufficient to conduct its business as it has been
conducted, is now being conducted and is currently proposed to be conducted. The
operations of the Company's business as now conducted and as currently proposed
to be conducted does not and will not conflict with or infringe, and no one has
asserted to the Company that such operation conflicts with or infringes, any
proprietary rights claimed, owned, possessed or used by any third party.

                           (b)      There are no claims, disputes, actions,
proceedings, suits or appeals pending against the Company with respect to any
MitoKor Proprietary Rights (other than those, if any, with respect to which
service of process or similar notice has not yet been made on the Company), and,
to the knowledge of the Company, none has been threatened against the Company.
To the knowledge of the Company, there are no facts or alleged facts which would
reasonably serve as a basis for any claim that the Company does not have the
unrestricted right to use, free of any rights or claims of others, all MitoKor
Proprietary Rights in the development, manufacture, use, sale or other
disposition of any or all products or services presently being used, furnished
or sold in the conduct of the business of the Company or currently contemplated
to be used, furnished or sold in the business of the Company.

                           (c)      To the knowledge of the Company, the MitoKor
Proprietary Rights have not been infringed by others.

                           (d)      There are no outstanding options, licenses
or agreements of any kind relating to the MitoKor Proprietary Rights, nor is the
Company bound by or a party to any options, licenses or agreements of any kind
with respect to the patents, trademarks, service marks, trade names, copyrights,
trade secrets, licenses, information, proprietary rights and processes of any
other person or entity.

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                           (e)      Neither the execution nor delivery of this
Agreement, nor the carrying of the Company's business by the employees of the
Company, nor the conduct of the Company's business as currently proposed, will,
to the Company's knowledge, conflict with or result in a breach of the terms,
conditions, or provisions of, or constitute a default under, any contract,
covenant or instrument under which any of such employees is now obligated.

                  3.7 COMPLIANCE WITH OTHER INSTRUMENTS, NONE BURDENSOME, ETC.
The Company is not in violation of any term of the Articles or Bylaws, nor is
the Company in violation of or in default in any material respect under the
terms of any mortgage, indenture, contract, agreement, instrument, judgment or
decree, the violation of which would have a material adverse effect on the
Company as a whole, and to the knowledge of the Company, is not in violation of
any order, statute, rule or regulation applicable to the Company, the violation
of which would have a material adverse effect on the Company. The execution,
delivery and performance of and compliance with this Agreement or the Rights
Agreement, and the issuance and sale of the Preferred Shares will not (a) result
in any such violation, or (b) be in conflict with or constitute a default under
any such term, or (c) result in the creation of any mortgage, pledge, lien,
encumbrance or charge upon any of the properties or assets of the Company
pursuant to any such term. To the knowledge of the Company, there is no such
term which materially adversely affects, or, so far as the Company may now
foresee, in the future may materially adversely affect, the business, condition,
affairs or operations of the Company or any of its properties or assets.

                  3.8 PROPRIETARY AGREEMENTS; EMPLOYEES. All technical and
management personnel presently employed by the Company have executed an
agreement regarding confidentiality and proprietary information, the form of
which has been made available to the Purchaser. The Company is not aware that
any of its employees is in violation thereof and will use reasonable efforts to
prevent any such violation. The Company is not aware that any of its employees
is obligated under any contract (including licenses, covenants or commitments of
any nature) or other agreement, or subject to any judgment, decree or order of
any court or administrative agency, that would interfere with the use of his or
her best efforts to promote the interests of the Company or that would conflict
with the Company's business as conducted or as proposed to be conducted or that
would prevent any such employee from assigning inventions to the Company. The
Company does not believe that it is or will be necessary for the Company to
utilize any inventions of any of its employees (or people it currently intends
to hire) made prior to their employment by the Company.

                  3.9 CONDITION OF PROPERTIES. All buildings, facilities,
machinery, equipment, fixtures, vehicles and other properties owned, leased or
used by the Company (a) are in good operating condition and repair (reasonable
wear and tear excepted), (b) to the best of the Company's knowledge, are being
operated in conformity with all applicable building, safety, zoning,
environmental, waste and other applicable ordinances, laws and regulations, and
(c) are adequate and sufficient for the Company's business as presently
conducted.

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                  3.10 LITIGATION, ETC. There is no action, proceeding or
investigation pending against the Company or, to the Company's knowledge, its
officers, directors or shareholders, or to the Company's knowledge, against
employees or consultants of the Company (or, to the Company's knowledge, any
basis therefor or threat thereof): (1) which might result, either individually
or in the aggregate, in (a) any material adverse change in the business,
conditions, affairs or operations of the Company or in any of its properties or
assets, or (b) any material adverse impairment of the right or ability of the
Company to carry on its business as now conducted or as proposed to be
conducted, or (c) any material liability on the part of the Company; or (2)
which questions the validity of this Agreement, the Rights Agreement or any
action taken or to be taken in connection herewith or therewith, including in
each case, without limitation, actions pending or threatened involving the prior
employment of any of the Company's employees, the use in connection with the
Company's business of any information or techniques allegedly proprietary to any
of its former employees, or their obligations under any agreements with prior
employers. The Company is not a party to or subject to the provisions of any
order, writ, injunction, judgment or decree of any court or government agency or
instrumentality. There is no action, suit, proceeding or investigation by the
Company currently pending or which the Company currently intends to initiate.

                  3.11 GOVERNMENTAL CONSENT, ETC. Based in part upon the
representations and warranties of the Purchaser in Section 4 hereof, no consent,
approval or authorization of or designation, declaration or filing with any
governmental authority on the part of the Company is required in connection
with: (a) the valid execution and delivery of this Agreement or the Rights
Agreement; or (b) the offer, sale or issuance of the Preferred Shares or the
issuance of the shares of Common Stock issuable upon conversion of the Preferred
Shares or (c) the obtaining of the consents, permits and waivers specified in
subsection 5.1(b) hereof, except the filing of the Articles and, if required,
filings or qualifications under applicable blue sky laws, which filings or
qualifications, if required, will have been timely filed or obtained after the
sale of the Preferred Shares.

                  3.12 OFFERING. In reliance on the representations and
warranties of the Purchaser in Section 4 hereof, the offer, sale and issuance of
the Preferred Shares in conformity with the terms of this Agreement will not
result in a violation of the requirements of Section 5 of the Securities Act of
1933, as amended (the "Securities Act") or the qualification or registration
requirements of the California Corporate Securities Law of 1968, as amended (the
"Law") or other applicable blue sky laws, and neither the Company nor any
authorized agent acting on its behalf will take any action hereafter that would
cause the loss of such exemption.

                  3.13 TAXES. The Company has filed all tax returns that are
required to have been filed with appropriate federal, state, county and local
governmental agencies or instrumentalities, except where the failure to do so
would not have a material adverse effect upon the Company, taken as a whole. The
Company has paid or established reserves for all material income, franchise and
other taxes, assessments, governmental charges, penalties, interest and fines
due and payable by them on or before the Closings. There is no pending dispute
with any taxing authority relating to any of such returns and the Company has no
knowledge of any proposed liability for any tax to be imposed upon the
properties or assets of the Company for which there is not an adequate reserve
reflected in the Financial Statements (as defined below) or, if adversely
determined against the Company, would have a material adverse effect. The
Company has not elected pursuant to the Internal Revenue Code of 1986, as
amended (the

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"Code"), to be treated as a Subchapter S corporation nor has it
made any other elections pursuant to the Code (other than elections that relate
solely to methods of accounting, depreciation or amortization) that would have a
material effect on the Company, its financial condition, its business as
presently conducted or proposed to be conducted or any of its properties or
material assets.

                  3.14 TITLE. The Company owns its properties and assets,
including the properties and assets reflected in the Financial Statements (as
defined in Section 3.16), free and clear of all liens, mortgages, loans or
encumbrances except liens for current taxes, and such encumbrances and liens
which arise in the ordinary course of business and do not materially impair the
Company's ownership or use of such property or assets. With respect to the
property and assets leased by the Company, the Company is in compliance with
such leases and holds valid leasehold interests free and clear of any liens,
claims or encumbrances.

                  3.15 MATERIAL CONTRACTS AND COMMITMENTS. All of the contracts,
mortgages, indentures, agreements, instruments and transactions to which the
Company is a party or by which it is bound (including purchase orders to the
Company or placed by the Company) which involve obligations of, or payments to,
the Company in excess of One Hundred Thousand Dollars ($100,000) and all
agreements between the Company and its officers, directors, consultants and
employees are either (i) attached as exhibits to this Agreement, or (ii) set
forth on the list attached hereto as EXHIBIT G (the "Contracts"), copies of
which have been made available to the Purchaser. All of the Contracts are valid,
binding and in full force and effect in all material respects and enforceable by
the Company in accordance with their respective terms in all material respects,
subject to the effect of applicable bankruptcy, insolvency, reorganization,
moratorium or other laws of general application relating to or affecting
enforcement of creditors' rights and rules or laws concerning equitable
remedies. The Company is not in material default under any of such Contracts. To
the Company's knowledge, no other party to any of the Contracts is in material
default thereunder.

                  3.16 FINANCIAL STATEMENTS. Attached hereto as EXHIBIT H are
audited financial statements for the fiscal year ended December 31, 1999 and
unaudited financial statements for the six (6) month period ended June 30, 2000
(the "Financial Statements"). The Financial Statements are complete and correct
in all material respects and have been prepared on a consistent basis throughout
the relevant periods. The Financial Statements accurately set out and describe
the financial condition and operating results of the Company as of the dates,
and during the periods, indicated therein. Except as set forth in the Financial
Statements, as of the Closing Dates the Company has no material liabilities of
any nature (matured or unmatured, fixed or contingent). The Company maintains
and will continue to maintain a standard system of accounting established and
administered in accordance with generally accepted accounting principles.

                  3.17 ABSENCE OF CHANGES. Except as contemplated by this
Agreement since June 30, 2000: (a) the Company has not entered into any
transaction which was not in the ordinary course of business, (b) there has been
no material adverse change in the condition (financial or otherwise) of the
business, property, assets or liabilities of the Company other than changes in
the ordinary course of business, none of which, individually or in the
aggregate, has been materially adverse, (c) there has been no damage to,
destruction of or loss of physical property (whether or not covered by
insurance) materially adversely affecting the assets,

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financial condition, operating results, business or operations of the Company,
(d) the Company has not declared or paid any dividend or made any distribution
on its stock, or redeemed, purchased or otherwise acquired any of its stock, (e)
the Company has not materially changed any compensation arrangement or agreement
with any of its key employees or executive officers, or materially changed the
rate of pay of its employees as a group, (f) the Company has not received notice
that there has been a cancellation of an order for the Company's products or a
loss of a customer of the Company, the cancellation or loss of which would
materially adversely affect the business of the Company, (g) the Company has not
changed or amended any material contract by which the Company or any of its
assets are bound or subject, (h) there has been no resignation or termination of
employment of any key officer or employee of the Company and the Company does
not know of any impending resignation or termination of employment of any such
key officer or employee, (i) there has been no labor dispute involving the
Company or its employees and none is pending or, to the best of the Company's
knowledge, threatened, (j) there has been no change, except in the ordinary
course of business, in the material contingent obligations of the Company (nor
in any contingent obligation of the Company regarding any director, shareholder
or key employee or officer of the Company) by way of guaranty, endorsement,
indemnity, warranty or otherwise, (k) there have been no loans made by the
Company to any of its employees, officers or directors other than travel
advances and other advances made in the ordinary course of business, (l) there
has been no waiver by the Company of a valuable right or of a material debt
owing to it, (m) there has not been any satisfaction or discharge of any lien,
claims or encumbrance or any payment of any obligation by the Company, except in
the ordinary course of business and which is not material to the assets,
properties, financial condition, operating results or business of the Company,
and (n) to the best of the knowledge of the Company, there has been no other
event or condition of any character pertaining to and materially adversely
affecting the assets or business of the Company.

                  3.18 OUTSTANDING INDEBTEDNESS. Except as disclosed in the
Financial Statements, the Company has no indebtedness for borrowed money which
it has directly or indirectly created, incurred, assumed or guaranteed, or with
respect to which it has otherwise become liable, directly or indirectly. The
Company has no material liability or obligation in excess of $50,000, absolute
or contingent, which is not shown or provided for in the latest Financial
Statements, except obligations under purchase orders, sales contracts, real
property leases, equipment leases or similar obligations incurred in the
ordinary course of business.

                  3.19 REGISTRATION RIGHTS. The Company has not granted or
agreed to grant any rights to register as that term is defined in the Rights
Agreement, including piggyback registration rights, to any person or entity.

                  3.20 CERTAIN TRANSACTIONS. The Company is not indebted,
directly or indirectly, to any of its officers, directors or shareholders or to
their spouses or children, in any amount whatsoever; and none of said officers,
directors or, to the best of the Company's knowledge, shareholders, or any
member of their immediate families, are indebted to the Company or have any
direct or indirect ownership interest in any firm or corporation with which the
Company is affiliated or with which the Company has a business relationship
(except as a holder of securities of a corporation whose securities are publicly
traded and which is subject to the reporting requirements of the Securities
Exchange Act of 1934, to the extent of owning not more than two percent (2%) of
the issued and outstanding securities of such corporation). No such officer,
director or shareholder, or any member of their immediate families, is, directly
or indirectly,

                                       8
<Page>

interested in any material contract with the Company. The Company is not
guarantor or indemnitor of any indebtedness of any other person, firm or
corporation.

                  3.21 CORPORATE DOCUMENTS; MINUTE BOOKS. Except for amendments
necessary to satisfy representations and warranties or conditions contained
herein (the form of which amendments has been approved by the Purchaser), the
Articles and Bylaws of the Company are in the form previously provided to the
Purchaser. The minute books of the Company have been made available to the
Purchaser and contain a complete summary of all meetings of directors and
shareholders since the time of incorporation of the Company.

                  3.22 EMPLOYEE BENEFIT PLANS. The Company does not have any
"employee benefit plan" as defined in the Employee Retirement Income Security
Act of 1974, as amended.

                  3.23 LABOR AGREEMENTS. The Company is not bound by or subject
to (and none of its assets or properties is bound by or subject to) any written
or oral, express or implied, contract, commitment or arrangement with any labor
union, and no labor union has requested or, to the Company's knowledge, has
sought to represent any of the employees, representatives or agents of the
Company. There is no strike or other labor dispute involving the Company
pending, or to the Company's knowledge, threatened, that could have a material
adverse effect on the assets, properties, financial condition, operating
results, or business of the Company (as such business is presently conducted and
as it is proposed to be conducted), nor is the Company aware of any labor
organization activity involving its employees.

                  3.24 REAL PROPERTY HOLDING CORPORATION. The Company is not a
"real property holding corporation" within the meaning of Section 897(c)(2) of
the United States Internal Revenue Code of 1986, as amended.

                  3.25 DISCLOSURE. No representation or warranty by the Company
in this Agreement, or in any document or certificate furnished or to be
furnished to the Purchaser pursuant hereto or in connection with the
transactions contemplated hereby, when taken together, contains or will contain
any untrue statement of a material fact or omits or will omit to state a
material fact necessary to make the statements made herein and therein, in the
light of the circumstances under which they were made, not misleading.

                  3.26 INSURANCE. The Company maintains insurance covering
property damage and liability reasonably prudent under commercially reasonable
practices.

                  3.27 SHAREHOLDER AGREEMENTS. Except as otherwise contemplated
by this Agreement, (a) there are no agreements or arrangements between the
Company and any of the Company's shareholders or to the Company's knowledge,
between any of the Company's shareholders which materially and adversely affect
any shareholder's ability or right freely to alienate or vote such shares and
(b) to the Company's knowledge, none of the Company's shareholders is affiliated
with or has any agreements or arrangements with any customer of, or supplier to,
the Company.

                                       9
<Page>

                  3.28 ENVIRONMENTAL MATTERS.

                           (a)      The Company has not caused or allowed, nor
has the Company contracted with any party for, the generation, use,
transportation, treatment, storage or disposal of any Hazardous Substances (as
defined below) in connection with the operations of its business or otherwise.

                           (b)      The Company, the operations of its business,
and any real property that the Company owns, leases, or otherwise occupies or
uses (the "Premises") are in compliance with all applicable Environmental Laws
(as defined below) and orders or directives of any governmental authorities
having jurisdiction under such Environmental Laws including, without limitation,
any Environmental Laws or orders or directives with respect to any cleanup or
remediation of any release or threat of release of Hazardous Substances.

                           (c)      The Company has not received any citation,
directive, letter or other communication, written or oral, or any notice of any
proceedings, claims or lawsuits, from any person, entity or governmental
authority arising out of the ownership or occupation of the Premises, or the
conduct of its operations, nor is it aware of any basis thereof.

                           (d)      The Company has obtained and is maintaining
in full force and effect all necessary permits, licenses and approvals required
by any Environmental Laws applicable to the Premises and the business operations
conducted thereon (including operations conducted by tenants on the Premises)
and is in compliance with all such permits, licenses and approvals.

                           (e)      The Company has not caused, or allowed a
release, or a threat of release, of any Hazardous Substance unto, nor to the
best of the Company's knowledge has the Premises or any property at or near the
Premises ever been subject to a release, or a threat of a release, of any
Hazardous Substance.

         The term, "Environmental Laws" shall mean any federal, state or local
law, ordinance or regulation pertaining to the protection of human health or the
environment including, without limitation, the Comprehensive Environmental
Response, Compensation and Liability Act, 42 U.S.C. Sections 9601, et seq.,
Emergency Planning and Community Right-to-Know Act, 42 U.S.C. Sections 11001, et
seq., and the Resource Conservation and Recovery Act, 42 U.S.C. Sections 6901,
et seq.

         The term, "Hazardous Substance" includes oil and petroleum products,
asbestos, polychlorinated biphenyls and urea formaldehyde, and any other
materials classified as hazardous or toxic under any Environmental Laws.

                  3.29 MANUFACTURING RIGHTS. The Company has not granted rights
to manufacture, produce, license or sell its products to any other person and is
not bound by any agreement which affects the Company's exclusive right to
manufacture or sell its products.

                  3.30 ASSUMPTIONS, GUARANTIES, ETC. OF INDEBTEDNESS OF OTHER
PERSONS. The Company has not assumed, guaranteed, endorsed or otherwise become
directly or contingently liable on any indebtedness of any other person
(including, without limitation, liability by way of agreement, contingent or
otherwise, to purchase, to provide funds for payment, to supply funds

                                       10
<Page>

to or otherwise invest in the debtor, or otherwise to assure the creditor
against loss), except for guaranties by endorsement of negotiable instruments
for deposit or collection in the ordinary course of business.

                  3.31 MATERIAL CUSTOMERS AND SUPPLIERS. No material customer
of, or material supplier to, the Company has terminated, materially reduced or
threatened to terminate or materially reduce its purchases from or provision of
products or services to the Company, as the case may be.

         4. REPRESENTATIONS AND WARRANTIES OF PURCHASER AND RESTRICTIONS ON
TRANSFER IMPOSED BY THE SECURITIES ACT.

                  4.1 REPRESENTATIONS AND WARRANTIES BY THE PURCHASER. The
Purchaser represents, warrants, acknowledges and covenants to the Company as of
the date hereof and as of the Closing Dates as follows:

                           (a)      INVESTMENT INTENT. This Agreement is made
with the Purchaser in reliance upon the Purchaser's representations to the
Company, evidenced by the Purchaser's execution of this Agreement, that the
Purchaser is acquiring the Preferred Shares and the Common Stock issuable upon
conversion of the Preferred Shares (collectively the "Securities") for
investment for the Purchaser's own account, not as nominee or agent, and not
with a view to, or for resale in connection with, any distribution or public
offering thereof within the meaning of the Securities Act and the Law. The
Purchaser has the full right, power and authority to enter into and perform this
Agreement and the Rights Agreement, and this Agreement and the Rights Agreement
constitute valid and binding obligations upon it.

                           (b)      PREFERRED SHARES NOT REGISTERED. The
Purchaser understands and acknowledges that the offering of the Preferred Shares
pursuant to this Agreement will not be registered under the Securities Act or
qualified under any blue sky laws on the grounds that the offering and sale of
securities contemplated by this Agreement are exempt from registration under the
Securities Act pursuant to Section 4(2) thereof and exempt from registration
pursuant to Section 25102(f) of the Law, and other applicable state securities
or blue sky laws, and that the Company's reliance upon such exemptions is
predicated upon the Purchaser's representations set forth in this Agreement. The
Purchaser acknowledges and understands that the Securities must be held
indefinitely unless the Securities are subsequently registered under the
Securities Act and qualified under applicable blue sky laws or an exemption from
such registration and such qualification is available.

                           (c)      NO TRANSFER. The Purchaser covenants that in
no event will it dispose of any of the Securities (other than in conjunction
with an effective registration statement for the Securities under the Securities
Act or in compliance with Rule 144 promulgated under the Securities Act) unless
and until (i) the Purchaser shall have notified the Company of the proposed
disposition and shall have furnished the Company with a statement of the
circumstances surrounding the proposed disposition, and (ii) if reasonably
requested by the Company, the Purchaser shall have furnished the Company with an
opinion of counsel satisfactory in form and substance to the Company to the
effect that (x) such disposition will not require registration under the
Securities Act and (y) appropriate action necessary for compliance

                                       11
<Page>

with the Securities Act, the Law and any other applicable state, local or
foreign law has been taken.

                           (d)      KNOWLEDGE AND EXPERIENCE. The Purchaser is
an investor in securities of companies in the development stage and acknowledges
that it is able to fend for itself, can bear the economic risk of its investment
and has such knowledge and experience in financial or business matters that it
is capable of evaluating the merits and risks of the investment in the Preferred
Shares. The Purchaser has been furnished with and has had access to such
information as the Purchaser considered necessary to make a determination as to
the purchase of the securities.

                           (e)      NOT ORGANIZED TO PURCHASE. The Purchaser has
not been organized for the purpose of purchasing the Securities.

                           (f)      HOLDING REQUIREMENTS. The Purchaser
understands that if the Company does not (i) register its Common Stock with the
Securities and Exchange Commission ("SEC") pursuant to Section 12 of the
Securities Exchange Act of 1934, as amended (the "Exchange Act"), (ii) become
subject to Section 15(d) of the Exchange Act, (iii) supply information pursuant
to Rule 15c2-11 thereunder, or (iv) have a registration statement covering the
Securities (or a filing pursuant to the exemption from registration under
Regulation A of the Securities Act covering the Securities) under the Securities
Act in effect when it desires to sell the Securities, such Purchaser may be
required to hold the Securities for an indeterminate period. Such Purchaser also
understands that any sale of the Securities that might be made by the Purchaser
in reliance upon Rule 144 under the Securities Act may be made only in limited
amounts in accordance with the terms and conditions of that rule.

                  4.2 LEGENDS. Each certificate representing the Securities
may be endorsed with the following legends:

                           (a)      FEDERAL LEGEND. THE SECURITIES REPRESENTED
BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933,
AS AMENDED (THE "ACT") AND ARE "RESTRICTED SECURITIES" AS DEFINED IN RULE 144
PROMULGATED UNDER THE ACT. THE SECURITIES MAY NOT BE SOLD OR OFFERED FOR SALE OR
OTHERWISE DISTRIBUTED EXCEPT (i) IN CONJUNCTION WITH AN EFFECTIVE REGISTRATION
STATEMENT FOR THE SHARES UNDER THE ACT OR (ii) IN COMPLIANCE WITH RULE 144, OR
(iii) PURSUANT TO AN OPINION OF COUNSEL, SATISFACTORY TO THE COMPANY, THAT SUCH
REGISTRATION OR COMPLIANCE IS NOT REQUIRED AS TO SAID SALE, OFFER OR
DISTRIBUTION.

                           (b)      OTHER LEGENDS. Any other legends required by
the Law or other applicable state blue sky laws.

The Company need not register a transfer of legended Securities, and may also
instruct its transfer agent not to register the transfer of the Securities,
unless the conditions specified in each of the foregoing legends are satisfied.

                                       12
<Page>

                  4.3 REMOVAL OF LEGEND AND TRANSFER RESTRICTIONS. Any legend
endorsed on a certificate pursuant to subsection 4.2(a) and the stop transfer
instructions with respect to such legended Securities shall be removed, and the
Company shall issue a certificate without such legend to the holder of such
Securities if such Securities are registered and sold under the Securities Act
and a prospectus meeting the requirements of Section 10 of the Securities Act is
available or if such holder satisfies the requirements of Rule 144(k) and, where
reasonably deemed necessary by the Company, provides the Company with an opinion
of counsel for such holder of the Securities, reasonably satisfactory to the
Company, to the effect that (i) such holder, meets the requirements of Rule
144(k) or (ii) a public sale, transfer or assignment of such Securities may be
made without registration.

                  4.4 RULE 144. The Purchaser is aware of the adoption of Rule
144 by the SEC promulgated under the Securities Act, which permits limited
public resales of securities acquired in a nonpublic offering, subject to the
satisfaction of certain conditions. The Purchaser understands that under Rule
144, the conditions include, among other things: the availability of certain
current public information about the issuer and the resale occurring not less
than one year after the party has purchased and paid for the securities to be
sold.

         5. CONDITIONS TO CLOSING.

                  5.1 CONDITIONS TO PURCHASERS' OBLIGATIONS. The obligations of
the Purchaser to purchase the Preferred Shares at the Closings are subject to
the fulfillment to its satisfaction, on or prior to the Closing Dates, of the
following conditions, any of which may be waived in accordance with the
provisions of subsection 7.1 hereof:

                           (a)      REPRESENTATIONS AND WARRANTIES CORRECT;
PERFORMANCE OF OBLIGATIONS. The representations and warranties made by the
Company in Section 3 hereof shall be true and correct when made, and shall be
true and correct on the Closing Dates with the same force and effect as if they
had been made on and as of said date. The Company's business and assets shall
not have been adversely affected in any material way prior to the Closing Dates.
The Company shall have performed all obligations and conditions herein required
to be performed or observed by it on or prior to the Closing Dates.

                           (b)      CONSENTS AND WAIVERS. The Company shall have
obtained in a timely fashion any and all consents, permits and waivers necessary
or appropriate for consummation of the transactions contemplated by this
Agreement.

                           (c)      FILING OF THE ARTICLES. The Articles shall
have been filed with the Secretary of State of California.

                           (d)      RIGHTS AGREEMENT. The Company and the
Purchaser shall have executed and delivered the Rights Agreement in the form
attached as EXHIBIT C hereto.

                           (e)      COMPLIANCE CERTIFICATE.  The Company shall
have delivered a Certificate, executed by the President of the Company, dated
the Closing Dates, certifying to the fulfillment of the conditions specified in
subsections (a), (b), (c) and (e) of this section 5.1.

                                       13
<Page>

                           (f)      STATE SECURITIES LAW.  The sale of the
Preferred Shares shall have been qualified with (a) the Commissioner of
Corporations of the State of California or an exemption from such qualification
shall have been obtained and (b) any other applicable state's securities law,
and evidence of all such qualifications shall have been furnished to the
Purchasers' special counsel.

                           (g)      OPINION OF COUNSEL.  The Purchaser shall
have received an opinion from the Company's counsel, in substantially the form
attached hereto as EXHIBIT I.

                           (h)      PROCEEDINGS AND DOCUMENTS.  All corporate
and other proceedings in connection with the transactions contemplated at the
Closings hereby and all documents and instruments incident to such transactions
shall be reasonably satisfactory in substance and form to the Purchaser and its
special counsel, and the Purchaser and its special counsel shall have received
all such counterpart originals or certified or other copies of such documents as
they may reasonably request.

                           (i)      RESERVATION OF COMMON STOCK.  The shares of
Common Stock issuable upon conversion of the Preferred Shares shall have been
duly authorized and reserved for issuance upon such conversion.

                  5.2 CONDITIONS TO OBLIGATIONS OF THE COMPANY. The Company's
obligation to sell and issue the Preferred Shares at the Closings is subject to
the condition that the representations and warranties made by the Purchaser in
Section 4 hereof shall be true and correct when made, and shall be true and
correct on the Closing Dates with the same force and effect as if they had been
made on and as of said date.

         6. AFFIRMATIVE COVENANTS OF THE COMPANY.  The Company hereby
covenants and agrees as follows:

                  6.1 FINANCIAL INFORMATION. Until the first to occur of (a) the
date on which the Company is required to file a report with the SEC pursuant to
Section 13(a) of the Exchange Act, by reason of the Company having registered
any of its securities pursuant to Section 12(g) of the Exchange Act or (b)
quotations for the Common Stock of the Company are reported by the automated
quotations system operated by the National Association of Securities Dealers,
Inc. or by an equivalent quotations system or (c) shares of the Common Stock of
the Company are listed on a national securities exchange registered under
Section 6 of the Exchange Act, the Company will furnish to each Purchaser:

                           (i)      as soon as practicable after the end of each
fiscal year, and in any event within 120 days thereafter, consolidated balance
sheets of the Company and its subsidiaries, if any, as at the end of such fiscal
year, and consolidated statements of operations and consolidated statements of
changes in financial position (or equivalent cash flow statements if required by
the Financial Accounting Standards Board) of the Company and its subsidiaries,
if any, for such year, prepared in accordance with generally accepted accounting
principles, all in reasonable detail and, certified by independent public
accountants of recognized national standing selected by the Company, and

                                       14
<Page>

                           (ii)     so long as the Purchaser owns an aggregate
of at least thirty percent (30%) of the Preferred Shares acquired at the
Closings (including any Common Stock issued upon conversion of any Preferred
Shares) as soon as practicable after the end of each month and each quarter
(except the last month and last quarter of the fiscal year), and in any event
within 30 and 45 days, respectively, thereafter, consolidated balance sheets of
the Company and its subsidiaries, if any, as of the end of such month or
quarter; and consolidated statements of income (or equivalent cash flow
statements if required by the Financial Standards Board), for such month or
quarter and for the current fiscal year to date, prepared in accordance with
generally accepted accounting principles (except for required footnotes), all in
reasonable detail and signed, subject to changes resulting from year-end audit
adjustments, by the principal financial officer or chief executive officer of
the Company, and

                           (iii)    so long as the Purchaser owns an aggregate
of at least thirty percent (30%) of the Preferred Shares acquired at the
Closings (including any Common Stock issued upon conversion of any Preferred
Shares) as soon as practicable after its adoption or approval by the Company's
Board of Directors, but not later than the commencement of such fiscal year, an
annual plan for each fiscal year which shall include monthly capital and
operating expense budgets, cash flow statements, projected balance sheets and
profit and loss projections for each such month and for the end of the year,
itemized in such detail as the Board of Directors may reasonably determine. In
addition, within 30 days after the end of each calendar year, the Company will
provide the Purchaser with a capitalization table showing (i) all stock of the
Company issued and outstanding for each class and series of stock and (ii) all
options and warrants outstanding.

                  6.2 CONFLICTS OF INTERESTS. The Company shall use its best
efforts to ensure that the Company's employees, during the term of their
employment with the Company, do not engage in activities which would result in a
conflict of interest with the Company. The Company's obligations hereunder
include, but are not limited to, requiring that the Company's employees devote
their primary productive time, ability and attention to the business of the
Company (provided, however, the Company's employees may engage in other business
activity if such activity does not materially interfere with their obligations
to the Company), requiring that the Company's employees enter into agreements
regarding proprietary information and confidentiality and preventing the
Company's employees from engaging or participating in any business that is in
competition with the business of the Company.

                  6.3 KEY MAN INSURANCE.  The Company shall use reasonable
efforts to maintain in force, until canceled or modified with the approval of
the Company's Board of Directors, insurance policies on the lives of Walter H.
Moos and Robert E. Davis naming the Company as holder and beneficiary.

                  6.4 PROPRIETARY AGREEMENTS.  The Company will use reasonable
efforts to prevent any employee from violating the confidentiality and
proprietary information agreement entered into between the Company and each of
its employees.

                  6.5 FUTURE STOCK ISSUANCES. The Company agrees that after the
Closings it will not issue any shares of Common Stock (or grant any options,
warrants or other rights to purchase the same) to any employee, officer, or
director except pursuant to written agreements

                                       15
<Page>

which provide for vesting over a period of at least forty-eight (48) months
(with the initial vesting date to occur at least after twelve (12) months) and a
right of first refusal in favor of the Company in the event of any proposed
transfer unless such issuance or grant is approved by the Company's Board of
Directors and provided that no such agreement will require the Company to
repurchase or redeem any of such shares. This Section 6.5 will terminate upon
the termination of Section 6.1.

                  6.6 RULE 144. The Company covenants that (i) at all times
after the Company first becomes subject to the reporting requirements of Section
13 or 15(d) of the Securities Exchange Act of 1934, the Company will use its
best efforts to comply with the current public information requirements of Rule
144(c)(1) under the Securities Act; and (ii) at all such times as Rule 144 is
available for use by the Purchaser, the Company will furnish the Purchaser upon
request with all information within the possession of the Company required for
the preparation and filing of Form 144.

                  6.7 TRANSACTIONS WITH AFFILIATES. Except for transactions
contemplated by this Agreement or as otherwise approved by the Board of
Directors, the Company shall not enter into any transaction with any director,
officer, employee or holder of more than 5% of the outstanding capital stock of
any class or series of capital stock of the Company, member of the immediate
family (as defined in the instructions to Regulation S-K item 404(a) under the
Securities Act of 1933, as amended) of any such person, or any corporation,
partnership, trust or other entity in which any such person, or member of the
immediate family of any such person, is a director, officer, trustee, partner or
holder of more than 5% of the outstanding capital stock thereof, except for
transactions on customary terms related to such person's employment.

                  6.8 INSPECTION RIGHTS. So long as the Purchaser owns an
aggregate of at least thirty percent (30%) of the Preferred Shares acquired by
the Purchaser at the Closings upon five (5) days' written notice provided to the
Company, the Purchaser shall have the right to visit and inspect any of the
properties of the Company, and to discuss its affairs, finances and accounts
with its officers, provided that the Company shall not be required at any time
to disclose any trade secrets or secret or other proprietary data, know-how or
other information, the disclosure of which the Company believes may adversely
affect its business, or any information or data that is classified by the United
States government or any agency or authority thereof. All inspection rights
granted by the Company to the Purchaser shall immediately terminate upon the
closing of the Company's initial registered underwritten public offering.

         7. MISCELLANEOUS.

                  7.1 WAIVERS AND AMENDMENTS. With the written consent of the
record holders of at least sixty-six and two-thirds percent (66 2/3%) of the
Preferred Shares, the obligations of the Company and the rights of the holders
of the Preferred Shares under this Agreement may be waived or amended (either
generally or in a particular instance); provided, however, that no such waiver
or amendment shall reduce the aforesaid proportion of Preferred Shares, the
holders of which are required to consent to any waiver or supplemental
agreement, without the consent of the record holders of all of the Preferred
Shares. Upon the effectuation of each such waiver or amendment, the Company
shall promptly give written notice thereof to the record holders of the
Preferred Shares who have not previously consented thereto in writing. Except to
the extent provided in this subsection 7.1, this Agreement or any provision
hereof may be amended,

                                       16
<Page>

waived, discharged or terminated only by a statement in
writing signed by the party against which enforcement of the amendment, waiver,
discharge or termination is sought.

                  7.2 GOVERNING LAW. This Agreement shall be governed in all
respects by the laws of the State of California as such laws are applied to
agreements between California residents entered into and to be performed
entirely within California.

                  7.3 SURVIVAL. The representations, warranties, covenants and
agreements made herein shall survive the Closings of the transactions
contemplated hereby, notwithstanding any investigation made by the Purchaser.
All statements as to factual matters contained in any certificate or other
instrument delivered by or on behalf of the Company pursuant hereto or in
connection with the transactions contemplated hereby shall be deemed to be
representations and warranties by the Company hereunder as of the date of such
certificate or instrument.

                  7.4 SUCCESSORS AND ASSIGNS. Except as otherwise expressly
provided herein, the provisions hereof shall inure to the benefit of, and be
binding upon, the successors, assigns, heirs, executors and administrators of
the parties hereto.

                  7.5 ENTIRE AGREEMENT. This Agreement and the other documents
delivered pursuant hereto constitute the full and entire understanding and
agreement between the parties with regard to the subjects hereof and thereof and
they supersede, merge and render void every other prior written and/or oral
understanding or agreement among or between the parties hereto.

                  7.6 NOTICES, ETC. All notices and other communications
required or permitted hereunder shall be in writing and shall be delivered
personally, mailed by first class mail, postage prepaid, or delivered by courier
or overnight delivery, addressed (a) if to the Purchaser, at the Purchaser's
address set forth on the signature page hereto, or at such other address as the
Purchaser shall have furnished to the Company in writing or (b) if to the
Company, at its address set forth at the beginning of this Agreement, or at such
other address as the Company shall have furnished to the Purchaser in writing.
Notices that are mailed shall be deemed received five (5) days after deposit in
the United States mail. Notices sent by courier or overnight delivery shall be
deemed received two (days) after they have been so sent.

                  7.7 SEVERABILITY. In case any provision of this Agreement
shall be found by a court of law to be invalid, illegal or unenforceable, the
validity, legality and enforceability of the remaining provisions of this
Agreement shall not in any way be affected or impaired thereby.

                  7.8 TITLES AND SUBTITLES.  The titles of the sections and
subsections of this Agreement are for convenience of reference only and are not
to be considered in construing this Agreement.

                  7.9 COUNTERPARTS.  This Agreement may be executed in any
number of counterparts, each of which shall be an original, but all of which
together shall constitute one instrument.

                  7.10 DELAYS OR OMISSIONS.  No delay or omission to exercise
any right, power or remedy accruing to the Company or to any holder of any
securities issued or to be issued

                                       17
<Page>

hereunder shall impair any such right, power or remedy of the Company or such
holder, nor shall it be construed to be a waiver of any breach or default under
this Agreement, or an acquiescence therein, or of or in any similar breach or
default thereafter occurring; nor shall any delay or omission to exercise any
right, power or remedy or any waiver of any single breach or default be deemed a
waiver of any other right, power or remedy or breach or default theretofore or
thereafter occurring. All remedies, either under this Agreement, or by law
otherwise afforded to the Company or any holder, shall be cumulative and not
alternative.

         IN WITNESS WHEREOF, the parties hereby have executed this Stock
Purchase Agreement on the date first above written.

"COMPANY"

MITOKOR

By:  /S/ Walter H. Moos
   --------------------------------------------------
     Walter H. Moos
-----------------------------------------------------
(print name)

Title: Chairman & CEO
      -----------------------------------------------

                                       18
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                        EGM MEDICAL TECHNOLOGY FUND, L.P.

                                        By:  /s/ Marc Pentopoulos
                                              -------------------------------
                                              Marc Pentopoulos
                                              -------------------------------
                                              (print name)

                                        Title: Portfolio Manager
                                              -------------------------------

                                        EGM MEDICAL TECHNOLOGY OFFSHORE FUND

                                        By:   /s/ Marc Pentopoulos
                                              -------------------------------
                                              Marc Pentopoulos
                                              -------------------------------
                                              (print name)

                                        Title: Portfolio Manager
                                              -------------------------------

                                        ASGARD VENTURES

                                        By:   /s/ Marc Pentopoulos
                                              -------------------------------
                                              Marc Pentopoulos
                                              -------------------------------
                                              (print name)

                                        Title: Portfolio Manager
                                              -------------------------------

                                        MARC PENTOPOULOS
                                              /s/ Mark Pentopoulos
                                              -------------------------------

                                        KELLIE SERINGER
                                              /s/ Kellie Seringer
                                              -------------------------------

                                       19
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                       FIRST BIO VENTURE CAPITAL

                                        By:   /s/ Cheng Ming Lee
                                              -------------------------------
                                              Cheng Ming Lee
                                              -------------------------------
                                              (print name)

                                        Title: President
                                              -------------------------------

                                       20
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                       THE KAUFMANN FUND, INC.

                                       By:    /s/ Lawrence Auriana
                                              --------------------------
                                              Lawrence Auriana

                                       Title: Chairman of the Board

                                       21
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                       ORBITEX HEALTH & BIOTECHNOLOGY FUND, 2V1I

                                       By:   /s/ Tim Bepler
                                             -------------------------------
                                             Tim Bepler
                                             -------------------------------
                                             (print name)

                                       Title: Portfolio Manager
                                             -------------------------------

                                       ORBITEX HEALTH & BIOTECHNOLOGY FUND, T31B

                                        By:   /s/ Tim Bepler
                                              -------------------------------
                                              Tim Bepler
                                              -------------------------------
                                              (print name)

                                        Title: Portfolio Manager
                                              -------------------------------

                                       22
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                       ALTA CALIFORNIA PARTNERS, L.P.
                                       By:  Alta California Management Partners,
                                               LLC Its General Partner

                                       By:    /s/ Jean Deleage
                                              -------------------------------
                                              Member

                                              Jean Deleage
                                              -------------------------------
                                              (print name)

                                       Title:  Member
                                              -------------------------------

                                       ALTA EMBARCADERO PARTNERS, LLC

                                       By:    /s/ Elaine Walker
                                              -------------------------------
                                              Under Power of Attorney

                                              Elaine Walker
                                              -------------------------------
                                             (print name)

                                       Title: Under Power of Attorney
                                              -------------------------------

                                       23
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                       BIOTECHVEST, LLP

                                       By:   /s/ Steve D. Seder
                                             -------------------------------
                                             Steve D. Seder
                                             -------------------------------
                                             (print name)

                                       Title: VP of Biotechvest II, GP of
                                              Biotechvest LLP
                                             -------------------------------

                                       LIAM BIOTECHVEST, LLC

                                       By:   /s/ Martin Pajor
                                             -------------------------------
                                             Martin Pajor
                                             -------------------------------
                                             (print name)

                                       Title: Capital Member, Member of
                                              Administrative Committee
                                             -------------------------------

                                       BIOTECHVEST, INC.

                                       By:   /s/ William Farley
                                             -------------------------------
                                             William Farley
                                             -------------------------------
                                             (print name)

                                       Title: CEO
                                             -------------------------------

                                       24
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                      DOMAIN PARTNERS III, L.P.
                                      By: One Palmer Square Associates III, L.P.

                                      By:   /s/ Kathleen K. Schoemaker
                                            -------------------------------
                                            Kathleen K. Schoemaker
                                            -------------------------------
                                            (print name)

                                      Title: General Partner
                                            -------------------------------

                                      3i BIOSCIENCE INVESTMENT TRUST PLC
                                      By:      Hare & Co

                                      By:   /s/ Kathleen K. Schoemaker
                                            -------------------------------
                                            Kathleen K. Schoemaker
                                            -------------------------------
                                            (print name)

                                      Title: Attorney-in-Fact
                                            -------------------------------

                                       25
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                       FORWARD VENTURES IV, L.P.
                                       by: Forward IV Associates, its General
                                           Partner

                                       By:   /s/ Standish M. Fleming
                                             -------------------------------
                                             Standish M. Fleming
                                             -------------------------------
                                             (print name)

                                       Title: Managing Member
                                             -------------------------------

                                       FORWARD VENTURES IV B, L.P.
                                       by: Forward IV Associates, its General
                                           Partner

                                       By:   /s/ Standish M. Fleming
                                             -------------------------------
                                             Standish M. Fleming
                                             -------------------------------
                                             (print name)

                                       Title: Managing Member
                                             -------------------------------

                                       26
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                       NEUROSCIENCE PARTNERS LIMITED PARTNERSHIP
                                       By its General Partner, MDS Associates -
                                       Neuroscience Inc.

                                       By:   /s/ M. Callaghan
                                             -------------------------------
                                             Michael Callaghan
                                             -------------------------------
                                             (print name)

                                       Title: Vice President
                                             -------------------------------

                                       By:   /s/ Keith Dorrington
                                             -------------------------------
                                             Keith Dorrington
                                             -------------------------------
                                             (print name)

                                       Title: Vice President
                                             -------------------------------

                                       27
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                       C.V. SOFINNOVA VENTURES PARTNERS III

                                       By:   /s/ Michael Powell
                                             -------------------------------
                                             Michael Powell
                                             -------------------------------
                                             (print name)

                                       Title: Managing Director
                                             -------------------------------

                                       28
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                       THORNER VENTURES

                                       By:   /s/ Tom Thorner
                                             -------------------------------
                                             Tom Thorner
                                             -------------------------------
                                             (print name)

                                       Title: Managing General Partner
                                             -------------------------------

                                       29
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                       CHINA DEVELOPMENT INDUSTRIAL BANK INC.

                                       By:    /s/ Benny T. Hu
                                              -------------------------------
                                              Benny T. Hu

                                       Title: President

                                       30
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                       SORRENTO GROWTH PARTNERS I, L.P.
                                       By: Sorrento Equity Growth Partners I,
                                       L.P., Its General Partner
                                       By: Sorrento Growth, Inc.
                                             Its General Partner

                                       By:   /s/ Robert M. Jaffe
                                             -------------------------------
                                             Robert M. Jaffe, President

                                       SORRENTO VENTURES III, L.P.
                                       By: Sorrento Equity Partners III, L.P.
                                            Its General Partner
                                       By: Sorrento Associates, Inc.
                                            Its General Partner

                                       By:   /s/ Robert M. Jaffe
                                             -------------------------------
                                             Robert M. Jaffe, President

                                       SORRENTO VENTURES CE, L.P.
                                       By: Sorrento Equity Partners III, L.P.
                                            Its General Partner
                                       By: Sorrento Associates, Inc.
                                            Its General Partner

                                       By:   /s/ Robert M. Jaffe
                                             -------------------------------
                                             Robert M. Jaffe, President

                                       31
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                       BIOINVEST INC.

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

                                             -------------------------------
                                             (print name)

                                       Title:
                                             -------------------------------

                                       32
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                       FREDERICK W. FIELD

                                       By:   /s/ Fredrick W. Field
                                             -------------------------------
                                             Frederick W. Field

                                       33
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                   SERIES F PREFERRED STOCK PURCHASE AGREEMENT

                                       SORRENTO MITOKOR, a General Partnership

                                       By:   /s/ Robert E. Petersen
                                             -------------------------------
                                             Robert E. Petersen
                                             -------------------------------
                                             (print name)

                                       Title: General Partner
                                             -------------------------------

                                       34<Page>

                                                                   EXHIBIT 10.7

                                     MITOKOR

                              AMENDED AND RESTATED

                           INVESTORS' RIGHTS AGREEMENT

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

                                NOVEMBER 9, 2001

<Page>

                               TABLE OF CONTENTS

<Table>
<Caption>

                                                                            PAGE
<S>                                                                         <C>
    Registration Rights....................................................... 1
    1.1.  Definitions......................................................... 1
    1.2.  Demand Registration................................................. 2
    1.3.  Company Registration................................................ 4
    1.5.  Form S-3............................................................ 6
    1.5.  Expenses of Registration............................................ 7
    1.6.  Registration Procedures............................................. 7
    1.7.  Indemnification.................................................... 10
    1.8.  Information by Holder.............................................. 11
    1.9.  Rule 144 Reporting................................................. 12
    1.10. Transfer of Registration Rights.................................... 12
    1.11. "Market Stand-Off" Agreement....................................... 12
    1.12. Termination of Rights.............................................. 13
    1.13. Certain Limitation in Connection With
          Future Grants of Registration Rights............................... 13
    1.14. Allocation  of Registration Opportunities.......................... 13

2. Right of First Refusal to Purchase Equity Securities...................... 14
    2.1.  Purchase Right..................................................... 14
    2.2.  Notice of Intent to Sell and Issue................................. 14
    2.3.  Investor Failure to Purchase....................................... 14
    2.4.  Investor Purchase.................................................. 15
    2.5.  Excluded Securities................................................ 15
    2.6.  Termination........................................................ 15
    2.7.  Equity Securities.................................................. 15
    2.8.  Assignment of Purchase Right....................................... 15

3.  General.................................................................. 15
    3.1.  Waivers and Amendments............................................. 15
    3.2.  Governing Law...................................................... 16
    3.3.  Successors and Assigns............................................. 16
    3.4.  Entire Agreement................................................... 16
    3.5.  Notices, etc....................................................... 16
    3.6.  Severability....................................................... 16
    3.7.  Titles and Subtitles............................................... 17
    3.8.  Counterparts....................................................... 17
    3.9.  No Inconsistent Agreements......................................... 17
    3.10. Adjustments Affecting Registration Securities...................... 17

</Table>

                                      i
<Page>

                                     MITOKOR

                              AMENDED AND RESTATED

                           INVESTORS' RIGHTS AGREEMENT

     THIS AMENDED AND RESTATED INVESTORS' RIGHTS AGREEMENT (this "Agreement") is
entered into as of November 9, 2001, by and among MITOKOR, a California
corporation (the "Company"), and the entities and individuals listed on the
EXHIBIT A attached hereto (the "Investors"). After the date of this Agreement,
additional purchasers of Series F-1 Preferred Stock of the Company under the
Purchase Agreement (as defined below) who execute a counterpart signature page
to this Agreement shall become additional Investors hereunder effective as of
the date of their respective purchase of shares of Series F-1 Preferred Stock
from the Company without formally amending this Agreement, and upon each such
purchase, EXHIBIT A hereto shall be revised to reflect the addition of such
Investors as parties to this Agreement.

                                    RECITALS:

     A.   Concurrently herewith, the Company and certain of the Investors are
entering into a Series F-1 Preferred Stock Purchase Agreement pursuant to which
such Investors are purchasing from the Company and the Company is selling to the
Investors shares of the Company's Series F-1 Preferred Stock (the "Series F-1
Shares").

     B.   Certain of the Investors have previously acquired from the Company
shares, or the right to acquire shares, of the Company's (i) Series A-1
Preferred Stock (the "Series A-1 Shares"), (ii) Series B Preferred Stock, Series
B-1 Preferred Stock, Series B-2 Preferred Stock, Series B-3 Preferred Stock and
Series B-4 Preferred Stock (collectively, the "Series B Shares"), (iii) Series C
Preferred Stock (the "Series C Shares"), (iv) Series D Preferred Stock (the
"Series D Shares"), (v) Series E Preferred Stock (the "Series E Shares"), (vi)
Series F Preferred Stock (the "Series F Shares"), and (vii) Series G Preferred
Stock (the "Series G Shares"), and are parties to the Investors' Rights
Agreement dated June 22, 2001 (the "Prior Rights Agreement").

     C.   Pursuant to Section 3.1 of the Prior Agreement, holders of at least
66-2/3% of the Registrable Securities (as defined in the Prior Agreement) and
the Company now desire to amend and restate the Prior Agreement in order to set
forth certain registration and other rights of the parties as set forth below.

                                   AGREEMENT:

     NOW, THEREFORE, in consideration of the foregoing and of the mutual
promises and covenants contained herein, the parties agree as follows:

     1.   REGISTRATION RIGHTS.

          1.1. DEFINITIONS. As used in this Agreement, the following terms shall
have the following respective meanings:

                                      1
<Page>

               (a)  The terms "register," "registered" and "registration" refer
to a registration effected by the preparation and filing of a registration
statement in compliance with the Securities Act of 1933, as amended (the
"Securities Act"), and the declaration or ordering of the effectiveness of such
registration statement.

               (b)  The term "Registrable Securities" means (i) any and all
shares of Common Stock of the Company issued or issuable upon conversion of: the
Series A-1 Shares, Series B Shares, Series C Shares, the 16,000 shares of Series
C Preferred Stock issuable upon exercise of warrants dated March 20, 1997,
Series D Shares, Series D-1 Shares, the 7,000 shares of Series D Preferred Stock
issuable upon exercise of warrants dated March 23, 1998, the Series E Shares,
the 11,333 shares of Series E Preferred Stock issuable upon exercise of warrants
dated June 15, 1999, the 8,500 shares of Series E Preferred Stock issuable upon
exercise of warrants dated December 15, 1999, the Series F Shares, the 8,000
shares of Series F Preferred Stock issuable upon exercise of warrants dated June
21, 2001, the Series F-1 Shares, the Series G Shares (including all Series G
Shares related to the Contingent Consideration as such term is defined in that
certain Agreement and Plan of Merger and Reorganization, dated as of May 8,
2001, by and among the Company, Apollo BioPharmaceutics, Inc. and Mito
Acquisition Corp.) and up to 279,397 shares of Series G Preferred Stock issuable
upon exercise of the warrants to purchase Series G Shares (collectively
"Preferred Shares"), (ii) any and all shares of Common Stock of the Company
issued in lieu or in respect of stock referred to in clause (i) in any
reorganization, or (iii) stock issued in respect of the stock referred to in (i)
and (ii) as a result of a stock split, stock dividend, recapitalization or the
like; provided, however, that Registrable Securities shall not include shares of
Common Stock which have previously been registered or which have been sold to
the public either pursuant to a registration statement or Rule 144, or which
have been sold in a private transaction in which the transferor's rights under
this Agreement are not assigned. The terms "Holder" or "Holders" means any
person or persons to whom Registrable Securities were originally issued or
qualifying transferees under Section 1.10 hereof who hold Registrable
Securities.

               (c)  The term "Initiating Holders" means any Holder or Holders of
50% or greater of the aggregate of the Registrable Securities then outstanding.

               (d)  The term "SEC" means the Securities and Exchange Commission.

               (e)  The term "Registration Expenses" shall mean all expenses
incurred by the Company in complying with Sections 1.2, 1.3 and 1.4 hereof,
including, without limitation, all registration, qualification and filing fees,
printing expenses, escrow fees, fees and disbursements of counsel for the
Company, reasonable fees and disbursements of one counsel for the Holders, blue
sky fees and expenses, and the expense of any special audits incident to or
required by any such registration (but excluding the compensation of regular
employees of the Company which shall be paid in any event by the Company.)

          1.2. DEMAND REGISTRATION.

               (a)  REQUEST FOR REGISTRATION. In case the Company shall receive
from Initiating Holders a written request that the Company effect any
registration with respect to at least 25% of the aggregate number of Registrable
Securities then outstanding, the Company will:

                                      2
<Page>

                    (i)  promptly give written notice of the proposed
registration to all other Holders; and

                    (ii) as soon as practicable, use its best efforts to effect
all such registrations (including, without limitation, the execution of an
undertaking to file post-effective amendments, appropriate qualifications under
the applicable blue sky or other state securities laws and appropriate
compliance with exemptive regulations issued under the Securities Act and any
other governmental requirements or regulations) as may be so requested and as
would permit or facilitate the sale and distribution of all or such portion of
such Initiating Holder's or Initiating Holders' Registrable Securities as are
specified in such request, together with all or such portion of the Registrable
Securities of any Holder or Holders joining in such request as are specified in
a written request given within twenty (20) days after receipt of such written
notice from the Company referred to in Section 1.2(a) of this Agreement;
provided that the Company shall not be obligated to take any action to effect
such registration pursuant to this Section 1.2:

                         (A)  at any time prior to the earlier of (i) six (6)
months following the effective date of the registration statement under the
Securities Act for the Company's initial registered underwritten public offering
resulting in gross proceeds to the Company of at least $10,000,000 (the "IPO")
of its securities to the general public (other than a registration statement
relating either to the sale of securities to employees of the Company pursuant
to a stock option, stock purchase or similar plan or an SEC Rule 145
transaction) or (ii) April 30, 2003;

                         (B)  in any particular jurisdiction in which the
Company would be required to execute a general consent to service of process in
effecting such registration, qualification or compliance unless the Company is
already subject to service in such jurisdiction and except as required by the
Securities Act;

                         (C)  after the Company has effected two (2) such
registrations pursuant to this Section 1.2(a) and such registrations have been
declared or ordered effective;

                         (D)  if the Company has effected one (1) registration
pursuant to this Section 1.2(a), and such registration statement has been
declared or ordered effective, within the twelve (12) month period prior to the
date of such request; or

                         (E)  unless the anticipated aggregate proceeds, net of
underwriting discounts and commissions, for such registration exceeds ten
million dollars ($10,000,000).

     Subject to the foregoing clauses (A) through (E), the Company shall file a
registration statement covering the Registrable Securities so requested to be
registered as soon as practical, but in any event within one hundred twenty
(120) days, after receipt of the request or requests of the Initiating Holders;
provided, however, that if the Company shall furnish to such holders a
certificate signed by the Chief Executive Officer of the Company stating that in
the good faith judgment of the Board of Directors it would be detrimental to the
Company and its shareholders for such registration statement to be filed at the
date such filing would be required and it is

                                       3
<Page>

therefore essential to defer the filing of such registration statement, the
Company shall have an additional period of not more than one hundred twenty
(120) days after the expiration of the initial 120-day period within which to
file such registration statement; provided, however, that the Company may not
utilize this right more than once in any twelve month period.

               (b)  UNDERWRITING. If the Initiating Holders intend to distribute
the Registrable Securities covered by their request by means of an underwriting,
they shall so advise the Company as part of their request made pursuant to this
Section 1.2 and the Company shall include such information in the written notice
referred to in Section 1.2(a)(i). In such event, the underwriter shall be
selected by the Company and shall be reasonably acceptable to a majority in
interest of the Initiating Holders. The right of any Holder to registration
pursuant to this Section 1.2 shall be conditioned upon such Holder's
participation in such underwriting and the inclusion of such Holder's
Registrable Securities in the underwriting (unless otherwise mutually agreed by
a majority in interest of the Initiating Holders and such Holder) to the extent
provided herein. The Company shall (together with all Holders proposing to
distribute their securities through such underwriting) enter into an
underwriting agreement in customary form with the underwriter or underwriters.
Notwithstanding any other provision of this Section 1.2, if the underwriter
advises the Initiating Holders in writing that marketing factors require a
limitation of the number of shares to be underwritten, the Initiating Holders
shall so advise all Holders, and the number of shares of Registrable Securities
that may be included in the registration and underwriting shall be allocated
among all Holders thereof (including the Initiating Holders) in proportion, as
nearly as practicable, to the respective amounts of Registrable Securities held
by such Holders. If any Holder of Registrable Securities disapproves of the
terms of the underwriting, such Holder may elect to withdraw therefrom by
written notice to the Company, the underwriter and the Initiating Holders. Any
Registrable Securities which are excluded from the underwriting by reason of the
underwriter's marketing limitation or withdrawn from such underwriting shall be
withdrawn from such registration.

     If shares are so withdrawn from the registration or if the number of shares
of Registrable Securities to be included in such registration was previously
reduced as a result marketing factors, the Company shall then offer to all
persons who have retained the right to include securities in the registration
the right to include additional securities in the registration in an aggregate
amount equal to the number of shares so withdrawn, with such shares to be
allocated among the persons requesting additional inclusion in accordance with
Section 1.14 hereof.

               (c)  COMPANY SHARES. If the managing underwriter has not limited
the number of Registrable Securities to be underwritten, the Company may include
securities for its own account or for the account of others in such registration
if the managing underwriter so agrees and if the number of Registrable
Securities which would otherwise have been included in such registration and
underwriting will not thereby be limited.

          1.3. COMPANY REGISTRATION.

               (a)  REGISTRATION. If at any time or from time to time, the
Company shall determine to register any of its securities, for its own account
or the account of any of its shareholders, other than a registration on Form S-1
or S-8 relating solely to employee stock option or purchase plans, or a
registration on Form S-4 relating solely to an SEC Rule 145

                                       4
<Page>

transaction, or a registration on any other form (other than Form S-1, S-2, S-3,
SB-1 or SB-2, or their successor forms) or any successor to such forms, which
does not include substantially the same information as would be required to be
included in a registration statement covering the sale of Registrable
Securities, the Company will:

                    (i)  promptly give to each Holder written notice thereof and

                    (ii) except as set forth in Section 1.3(b) below, include in
such registration (and compliance), and in any underwriting involved therein,
all of the Registrable Securities requested to be registered by any Holder or
Holders who collectively hold at least 500,000 Registrable Securities in the
aggregate, provided that request(s) by such Holder(s) are delivered to the
Company by the Holder(s) within 20 days after receipt by the Holder(s) of the
written notice from the Company described in Section 1.2(a)(i) above.

               (b)  UNDERWRITING. If the registration of which the Company gives
notice is for a registered public offering involving an underwriting, the
Company shall so advise the Holders as a part of the written notice given
pursuant to Section 1.3(a)(i). In such event the right of any Holder to
registration pursuant to this Section 1.3 shall be conditioned upon such
Holder's participation in such underwriting and the inclusion of such Holder's
Registrable Securities in the underwriting to the extent provided herein. All
Holders proposing to distribute their securities through such underwriting shall
(together with the Company and the other shareholders distributing their
securities through such underwriting) enter into an underwriting agreement in
customary form with the underwriter or underwriters selected for such
underwriting by the Company. Notwithstanding any other provision of this Section
1.3, if the underwriter determines that marketing factors require a limitation
of the number of shares to be underwritten, and (i) if such registration is the
first registered offering of the sale of the Company's securities to the general
public, the underwriter may limit the number of Registrable Securities to be
included in the registration and underwriting, or may exclude Registrable
Securities entirely from such registration and underwriting, or (ii) if such
registration is other than the first registered offering of the sale of the
Company's securities to the general public, the underwriter may limit the amount
of securities to be included in the registration and underwriting by the
Company's shareholders; provided however, the number of Registrable Securities
to be included in such registration and underwriting under this Section 1.3(b)
shall not be reduced to less than thirty percent (30%) of the aggregate
securities included in such registration without the prior consent of at least a
majority in interest of the Holders who have requested their shares to be
included in such registration and underwriting. The Company shall so advise all
Holders of Registrable Securities which would otherwise be registered and
underwritten pursuant hereto, and the number of shares of Registrable Securities
that may be included in the registration and underwriting shall be allocated
among Holders requesting registration in proportion, as nearly as practicable,
to the respective amounts of Registrable Securities held by each of such Holders
as of the date of the notice pursuant to Section 1.3(a)(i) above. If any Holder
disapproves of the terms of the any such underwriting, he may elect to withdraw
therefrom by written notice to the Company and the underwriter. Any Registrable
Securities excluded or withdrawn from such underwriting shall be withdrawn from
such registration.

     If shares are so withdrawn from the registration or if the number of shares
of Registrable Securities to be included in such registration was previously
reduced as a result marketing

                                       5
<Page>

factors, the Company shall then offer to all persons who have retained the right
to include securities in the registration the right to include additional
securities in the registration in an aggregate amount equal to the number of
shares so withdrawn, with such shares to be allocated among the persons
requesting additional inclusion in accordance with Section 1.14 hereof.

     For any selling Holder which is a partnership or corporation, the partners,
retired partners and shareholders of such Holder, or the estates and family
members of any such partners and retired partners and any trusts for the benefit
of any of the foregoing persons shall be deemed to be a single selling Holder
such that any pro rata reduction with respect to such selling Holder shall be
based upon the aggregate amount of Registrable Securities owned by all entities
and individuals included in such selling Holder.

          1.4. FORM S-3. In addition to the rights and obligations set forth in
Section 1.2 above, if the Company shall receive from any Holder or Holders of
the Registrable Securities (the "S-3 Initiating Holder(s)") a written request
that the Company file a registration statement on Form S-3 (or any successor to
Form S-3) for a public offering of shares of Registrable Securities and any
related qualification or compliance, the reasonably anticipated aggregate price
to the public of which (net of underwriting discounts and commissions) would
exceed $1,000,000 and the Company is then a registrant entitled to use Form S-3
(or any successor form to Form S-3) to register the shares for such a re-sale
offering by the Holders, the Company will give prompt written notice of the
proposed registration, qualification and compliance to all other Holders and
shall use its best efforts to cause such shares to be registered for the
offering as may be requested as soon as practicable on Form S-3 (or any
successor form to Form S-3); provided, however the Company shall not be required
to effect a registration pursuant to this Section 1.4:

               (a)  in any particular jurisdiction in which the Company would be
required to execute a general consent to service of process in effecting such
registration, qualification or compliance unless the Company is already subject
to service in such jurisdiction and except as may be required by the Securities
Act;

               (b)  if the Company, within ten (10) days of the receipt of the
request of the S-3 Initiating Holder(s), gives notice of its bona fide intention
to effect the filing of a registration statement with the SEC within sixty (60)
days of receipt of such request (other than with respect to a registration
statement relating to a Rule 145 transaction, an offering solely to employees or
any other registration which is not appropriate for the registration of
Registrable Securities);

               (c)  during the period starting with the date of filing of, and
ending on a date one hundred eighty (180) days following the effective date of,
a registration statement described in (b) above or pursuant to Section 1.2 ,
provided that the Company is actively employing in good faith all reasonable
efforts to cause such registration statement to become effective and further
provided that no other person or entity could require the Company to file a
registration statement in such period;

               (d)  if the Company has effected two (2) registrations pursuant
to this Section 1.4 within the 12-month period prior to the date of such
request; or

                                       6
<Page>

               (e)  if the Company shall furnish to such S-3 Initiating
Holder(s) a certificate signed by the President of the Company stating that in
the good faith judgment of the Board of Directors of the Company, it would be
detrimental to the Company and its shareholders for such registration statement
to be filed on or before the date such filing would be required and it is
therefore essential to defer the filing of such registration statement, in which
case the Company shall have the right to defer such filing for a period of not
more than ninety (90) days after the furnishing of such a certificate of
deferral, provided that the Company may not defer such filing pursuant to this
Section 1.4 more than once in any 12-month period.

     In the event such S-3 Initiating Holder(s) propose to offer the shares of
Registrable Securities pursuant to this Section 1.4 by means of an underwriting,
the proposed underwriters shall be selected by the Company and shall be
reasonably acceptable to a majority in interest of the Initiating Holders. The
Company shall give written notice to all Holders of the receipt of a request for
registration pursuant to this Section 1.4 and shall provide a reasonable
opportunity for other Holders to participate in the registration, provided that
if the registration is for an underwritten offering, the terms of Section 1.2
(b) shall apply to all participants in such offering.

          1.5. EXPENSES OF REGISTRATION. All Registration Expenses incurred in
connection with any registration, qualification or compliance pursuant to this
Section 1 shall be borne by the Company except as follows:

               (a)  The Company shall not be required to pay for expenses of any
registration proceeding begun pursuant to Section 1.2 , the request for which
has been subsequently withdrawn by the Initiating Holders, in which case such
expenses shall be borne by the Holders requesting such withdrawal unless, at the
time of such withdrawal, the Holders have learned of a material adverse change
in the condition, business or prospects of the Company from that known to the
Initiating Holders at the time of their request.

               (b)  The Company shall not be required to pay fees or
disbursements of legal counsel of a Holder unless all the Holders specify one
special counsel.

               (c)  The Company shall not be required to pay underwriters' fees,
discounts or commissions relating to Registrable Securities.

          1.6. REGISTRATION PROCEDURES. In the case of each registration,
qualification or compliance effected by the Company pursuant to this Agreement,
the Company will keep each Holder participating therein advised in writing as to
the initiation of each registration, qualification and compliance and as to the
completion thereof. Except as otherwise provided in Section 1.5, at its expense
the Company will:

               (a)  Prepare and file with the SEC a registration statement with
respect to such Registrable Securities and use its best efforts to cause such
registration statement to become effective and keep such registration statement
effective for up to one hundred eighty (180) days or until the Holder or Holders
have completed the distribution described in the registration statement relating
thereto, whichever first occurs.

               (b)  Prepare and file with the SEC such amendments and
supplements to such registration statement and the prospectus used in connection
with such registration

                                       7
<Page>

statement as may be necessary to comply with the provisions of the Securities
Act with respect to the disposition of all securities covered by such
registration statement; provided, however, that with respect to paragraphs (a)
and (b) that before filing a registration statement or prospectus or any
amendments or supplements thereto, the Company will furnish to the Holders of
the Registrable Securities requested to be included in such registration copies
of all such documents proposed to be filed, which documents will be subject to
the review and comment of counsel of the Holder's choosing.

               (c)  Furnish to the Holders such numbers of copies of a
prospectus, including a preliminary prospectus, in conformity with the
requirements of the Securities Act, and such other documents as they may
reasonably request in order to facilitate the disposition of Registrable
Securities owned by them.

               (d)  Use its best efforts to register and qualify the securities
covered by such registration statement under such other securities or Blue Sky
laws of such jurisdictions as shall be reasonably requested by the Holders,
provided that the Company shall not be required in connection therewith or as a
condition thereto to qualify to do business or, except as required under the
Securities Act, to file a general consent to service of process in any such
states or jurisdictions.

               (e)  Cause all such Registrable Securities registered hereunder
to be listed on each securities exchange or automated quotation system on which
similar securities issued by the Company are then listed, and if listed on the
NASD automated quotation system, use its best efforts to secure designation of
all such Registrable Securities covered by such registration statement as a
NASDAQ "national market system security" within the meaning of Rule 11Aa2-1 of
the SEC, or, failing that, to secure NASDAQ authorization for such Registrable
Securities and, without limiting the generality of the foregoing, to arrange for
at least two market makers to register as such with respect to such Registrable
Securities with the NASD.

               (f)  Notify each seller of such Registrable Securities, at any
time when a prospectus relating thereto is required to be delivered under the
Securities Act, of the happening of any event as a result of which the
prospectus included in such registration statement contains an untrue statement
of a material fact or omits any fact necessary to make the statements therein
not misleading, and, at the request of any such seller, the Company will prepare
a supplement or amendment to such prospectus so that, as thereafter delivered to
the purchasers of such Registrable Securities, such prospectus will not contain
an untrue statement of a material fact or omit to state any fact necessary to
make the statements therein not misleading.

               (g)  Provide a transfer agent and registrar for all such
Registrable Securities not later than the effective date of such registration
statement.

               (h)  Enter into such customary agreements (including underwriting
agreements in customary form) and take all such other actions as any of the
Holders of the Registrable Securities to be included in such registration and
being sold, or the underwriter(s) or other Person(s) administering the offering,
if any, reasonably request in order to expedite or facilitate the disposition of
such Registrable Securities.

                                       8

<Page>

               (i)  Make available for inspection by any seller of Registrable
Securities, any underwriter or other Person participating in any disposition
pursuant to such registration statement and any attorney, accountant or other
agent retained by any such seller or underwriter, all financial and other
records, pertinent corporate documents and properties of the Company, and cause
the Company's officers, directors, employees and independent accountants to
supply all information reasonably requested by any such seller, underwriter,
attorney, accountant or agent in connection with such registration statement.

               (j)  Otherwise use its best efforts to comply with all applicable
rules and regulations of the SEC, and make available to its security holders, as
soon as reasonably practicable, an earnings statement covering the period of at
least twelve months beginning with the first day of the Company's first full
calendar quarter after the effective date of the registration statement, which
earnings statement will satisfy the provisions of Section 11(a) of the
Securities Act and Rule 158 thereunder.

               (k)  If any such registration or comparable statement refers to
any Holder by name or otherwise as the holder of any securities of the Company
and if in its sole and exclusive judgment, such Holder is or might be deemed to
be an underwriter or a controlling person of the Company, such Holder will have
the right to require (i) the insertion therein of language, in form and
substance satisfactory to such Holder and presented to the Company in writing,
to the effect that the holding by such Holder of such securities is not to be
construed as a recommendation by such Holder of the investment quality of the
Company's securities covered thereby and that such holding does not imply that
such holder will assist in meeting any future financial requirements of the
Company, or (ii) in the event that such reference to such Holder by name or
otherwise is not required by the Securities Act or any similar Federal statute
then in force, the deletion of the reference to such Holder.

               (l)  In the event of the issuance of any stop order suspending
the effectiveness of a registration statement, or of any order suspending or
preventing the use of any related prospectus or suspending the qualification of
any common stock included in such registration statement for sale in any
jurisdiction, the Company will use its best efforts promptly to obtain the
withdrawal of such order.

               (m)  Use its best efforts to cause such Registrable Securities
covered by such registration statement to be registered with or approved by such
other governmental agencies or authorities as may be necessary to enable the
sellers thereof to consummate the disposition of such Registrable Securities;

               (n)  Provide a cold comfort letter from the Company's independent
public accountants in customary form and covering such matters of the type
customarily covered by cold comfort letters to the Holders of the Registrable
Securities requested to be included in such registration; and

               (o)  Provide opinions of counsel covering all such matters
customarily covered regarding the registration of the Company's securities to
the Holders of the Registrable Securities requested to be included in such
registration.

                                       9

<Page>

          1.7. INDEMNIFICATION.

               (a)  The Company will indemnify and hold harmless each Holder of
Registrable Securities and each of its officers, directors and partners, legal
counsel, accountants, employees and each person controlling such Holder, with
respect to which such registration, qualification or compliance has been
effected pursuant to Agreement, and each underwriter, if any, and each person
who controls any underwriter of the Registrable Securities held by or issuable
to such Holder, against all claims, losses, expenses, damages and liabilities
(or actions in respect thereto) arising out of or based on any untrue statement
(or alleged untrue statement) of a material fact contained in any prospectus,
offering circular or other document (including any related registration
statement, notification or the like) incident to any such registration,
qualification or compliance, or based on 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, or any violation or alleged violation by
the Company of the Securities Act, the Securities Exchange Act of 1934 (the
"Exchange Act") and any state securities law or any rule or regulation
promulgated under the Securities Act, the Exchange Act or any state securities
law and relating to action or inaction required of the Company in connection
with any such registration, qualification or compliance, and will reimburse each
such Holder, each of its officers, directors and partners, legal counsel,
accountants, employees and each person controlling such Holder, each such
underwriter and each person who controls any such underwriter, within a
reasonable amount of time after incurred for any reasonable legal and other
expenses incurred by them in connection with investigating, defending or
settling any such claim, loss, damage, liability or action; provided, however,
that the indemnity agreement contained in this Section 1.7(a) shall not apply to
amounts paid in settlement of any such claim, loss, damage, liability, or action
if such settlement is effected without the consent of the Company (which consent
shall not be unreasonably withheld); and provided further, that the Company will
not be liable in any such case to the extent that any such claim, loss, damage
or liability arises out of or is based on any untrue statement or omission based
upon written information furnished to the Company by an instrument duly executed
by such Holder, controlling person or underwriter specifically for use therein.

               (b)  Each Holder will, if Registrable Securities held by or
issuable to such Holder are included in the securities as to which such
registration, qualification or compliance is being effected, indemnify and hold
harmless the Company, each of its directors and officers, each underwriter, if
any, of the Company's securities covered by such a registration statement, each
person who controls the Company within the meaning of the Securities Act, and
each other such Holder, each of its officers, directors and partners and each
person controlling such Holder, against all claims, losses, expenses, damages
and liabilities (or actions in respect thereof) arising out of or based on any
untrue statement (or alleged untrue statement) of a material fact contained in
any such registration statement, prospectus, offering circular or other
document, or 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, and will reimburse the Company, such Holders, such directors,
officers, partners, legal counsel, accountants, employees, each person
controlling such Holder or underwriters for any reasonable legal or other
expenses incurred in connection with investigating, defending or settling any
such claim, loss, damage, liability or action, in each case to the extent, but
only to the extent, that such untrue statement (or alleged untrue statement) or
omission (or alleged omission) is made in such registration

                                       10
<Page>

statement, prospectus, offering circular or other document in reliance upon and
in conformity with written information furnished to the Company by the Holder in
an instrument duly executed by such Holder specifically for use therein;
provided, however, that the indemnity agreement contained in this Section 1.7(b)
shall not apply to amounts paid in settlement of any such claim, loss, damage,
liability or action if such settlement is effected without the consent of the
Holder (which consent shall not be unreasonably withheld); and provided further,
that the total amount for which any Holder shall be liable under this Section
1.7(b) shall not in any event exceed the aggregate proceeds received by such
Holder from the sale of Registrable Securities held by such Holder in such
registration. The obligation to indemnify will be individual, not joint and
several, for each Holder.

               (c)  Each party entitled to indemnification under this Section
1.7 (the "Indemnified Party") shall give notice to the party required to provide
indemnification (the "Indemnifying Party") promptly after such Indemnified Party
has actual knowledge of any claim as to which indemnity may be sought, and shall
permit the Indemnifying Party to assume the defense of any such claim or any
litigation resulting therefrom; provided that counsel for the Indemnifying
Party, who shall conduct the defense of such claim or litigation, shall be
approved by the Indemnified Party (whose approval shall not be unreasonably
withheld), and the Indemnified Party may participate in such defense at such
party's expense; and provided further, that the failure of any Indemnified Party
to give notice as provided herein shall not relieve the Indemnifying Party of
its obligations hereunder, unless such failure resulted in prejudice to the
Indemnifying Party; and provided further, that an Indemnified Party (together
with all other Indemnified Parties which may be represented without conflict by
one counsel) shall have the right to retain one separate counsel, with the fees
and expenses to be paid by the Indemnifying Party, if representation of such
Indemnified Party by the counsel retained by the Indemnifying Party would be
inappropriate due to actual or potential differing interests between such
Indemnified Party and any other party represented by such counsel in such
proceeding. No Indemnifying Party, in the defense of any such claim or
litigation, shall, except with the consent of each Indemnified Party, consent to
entry of any judgment or enter into any settlement which does not include as an
unconditional term thereof the giving by the claimant or plaintiff to such
Indemnified Party of a release from all liability in respect to such claim or
litigation.

               (d)  The obligations of the Company and Holders under this
Section 1.7 shall survive the completion of any offering of Registrable
Securities in a registration statement under this Section 1, and otherwise and
will survive the transfer of the securities.

          1.8. INFORMATION BY HOLDER. Any Holder or Holders of Registrable
Securities included in any registration shall promptly furnish to the Company
such information regarding such Holder or Holders and the distribution proposed
by such Holder or Holders as the Company may reasonably request in writing and
as shall be required in connection with any registration, qualification or
compliance referred to herein.

          1.9. RULE 144 REPORTING. With a view to making available to Holders
the benefits of certain rules and regulations of the SEC which may permit the
sale of the Registrable Securities to the public without registration, the
Company agrees at all times to:

                                       11
<Page>

               (a)  make and keep public information available, as those terms
are understood and defined in SEC Rule 144, after ninety (90) days after the
effective date of the first registration filed by the Company for an offering of
its securities to the general public;

               (b)  take such action, including the voluntary registration of
its Common Stock under Section 12 of the Exchange Act, as is necessary to enable
the Holders to utilize Form S-3 for the sale of their Registrable Securities,
such action to be taken as soon as practicable after the end of the fiscal year
in which the first registration statement filed by the Company for the offering
of its securities to the general public is declared effective;

               (c)  file with the SEC in a timely manner all reports and other
documents required of the Company under the Securities Act and the Exchange Act
(at any time after it has become subject to such reporting requirements); and

               (d)  so long as a Holder owns any Registrable Securities, to
furnish to such Holder forthwith upon request a written statement by the Company
as to its compliance with the reporting requirements of said Rule 144 (at any
time after ninety (90) days after the effective date of the first registration
statement filed by the Company for an offering of its securities to the general
public), and of the Securities Act and the Exchange Act (at any time after it
has become subject to such reporting requirements), a copy of the most recent
annual or quarterly report of the Company, and such other reports and documents
so filed by the Company as the Holder may reasonably request in complying with
any rule or regulation of the SEC allowing the Holder to sell any such
securities without registration.

          1.10. TRANSFER OF REGISTRATION RIGHTS. Holders' rights to cause the
Company to register their securities and keep information available, granted to
them by the Company under Sections 1.2, 1.3, 1.4 and 1.9, may be assigned to a
transferee or assignee of one hundred percent (100%) of a Holder's Registrable
Securities, provided that the Company is given written notice by such Holder at
the time of or within a reasonable time after said transfer, stating the name
and address of said transferee or assignee and identifying the securities with
respect to which such registration rights are being assigned. The foregoing one
hundred percent (100%) limitation shall not apply, however, to (i) transfers by
a Holder which is a limited partnership to its partners or retired partners, an
affiliated limited partnership or other affiliate of such Holder provided,
however, that all such transferees or assignees agree in writing to appoint a
single representative as their attorney-in-fact for the purpose of receiving any
notices and exercising their rights under this Section 1, (ii) transfers to
another holder of Registrable Securities who already possesses registration
rights pursuant to the terms of this Investors' Rights Agreement, (iii)
transfers to a transferee or assignee acquiring more than ten percent (10%) of
the Company's outstanding capital stock, or (iv) transfers by a Holder to
Holder's ancestors, descendants or spouse of an individual holder or to trusts
for the benefit of such person or persons, provided, however, in any such
transfer, the transferee shall agree in writing to be bound by the terms of this
Agreement as if an original signatory thereto.. The Company may prohibit the
transfer of any Holders' rights under this Section 1.10 to any proposed
transferee or assignee who the Company reasonably believes is a competitor of
the Company.

          1.11. "MARKET STAND-OFF" AGREEMENT. Each Holder hereby agrees that,
during the period of time (not to exceed 180 days) specified by the Company and
an underwriter of

                                       12
<Page>

common stock or other securities of the Company following the effective date of
a registration statement of the Company filed under the Securities Act, it shall
not, to the extent requested by the Company and such underwriter, directly or
indirectly sell, offer to sell, contract to sell (including, without limitation,
any short sale), grant any option to purchase, pledge or otherwise transfer or
dispose of (other than to donees who agree to be similarly bound) any securities
of the Company held by it at any time during such period except common stock
included in such registration; provided, however, that such agreement shall not
be required unless all officers, directors and key employees of the Company and
all shareholders holding an equivalent or greater number of shares (on a common
stock equivalent basis) of Company capital stock (collectively the "Company
Signatories") also agree to be bound by such restrictions, and such agreements
shall be no more restrictive on the Holders than the restrictions applicable to
the Company Signatories.

     In order to enforce the foregoing covenant, the Company may impose
stop-transfer instructions with respect to the Registrable Securities of each
Holder (and the shares of securities of every other person subject to the
foregoing restriction) until the end of such period.

          1.12. TERMINATION OF RIGHTS. The rights of (a) any particular Holder
to cause the Company to register securities under Sections 1.2, 1.3 and 1.4
shall terminate with respect to such Holder following a bona fide, firmly
underwritten public offering of shares of Common Stock registered under the
Securities Act at such time as such Holder is able to dispose of all of his or
its Registrable Securities in one three-month period pursuant to the provisions
of Rule 144, provided that such Holder holds Registrable Securities constituting
less than 1% of the outstanding voting stock of the Company, or is eligible to
sell such Registrable Securities pursuant to Rule 144(k) and (b) all Holders to
cause the Company to register securities under Sections 1.2, 1.3 and 1.4 shall
terminate as to all Holders upon the expiration of seven (7) years from the
closing of the IPO.

          1.13. CERTAIN LIMITATIONS IN CONNECTION WITH FUTURE GRANTS OF
REGISTRATION RIGHTS. From and after the date of this Agreement, the Company
shall not, without the prior written consent of the Holders of at least a
majority of the outstanding Registrable Securities, enter into any agreement
with any person or persons providing for the granting to such person of
registration rights superior to those granted to Holders pursuant to this
Section 1, or of registration rights which might cause a reduction in the number
of shares includable by the Holders in any offering pursuant to Section 1.2 or
any offering subject to Section 1.3.

          1.14. ALLOCATION OF REGISTRATION OPPORTUNITIES. In any circumstance in
which all of the Registrable Securities and other shares of Common Stock of the
Company (including shares of Common Stock issued or issuable upon conversion of
shares of any currently unissued series of Preferred Stock of the Company) with
registration rights (the "Other Shares") requested to be included in a
registration on behalf of the Holders or other selling stockholders cannot be so
included as a result of limitations of the aggregate number of shares of
Registrable Securities and Other Shares that may be so included, the number of
shares of Registrable Securities and Other Shares that may be so included shall
be allocated among the Holders and other selling stockholders requesting
inclusion of shares pro rata on the basis of the number of shares of Registrable
Securities and Other Shares that would be held by such Holders and other selling
stockholders, assuming conversion; provided, however, that such allocation shall
not operate to

                                       13
<Page>

reduce the aggregate number of Registrable Securities and Other Shares to be
included in such registration, if any Holder or other selling stockholder does
not request inclusion of the maximum number of shares of Registrable Securities
and Other Shares allocated to him pursuant to the above-described procedure, the
remaining portion of his allocation shall be reallocated among those requesting
Holders and other selling stockholders whose allocations did not satisfy their
requests pro rata on the basis of the number of shares of Registrable Securities
and Other Shares which would be held by such Holders and other selling
stockholders, assuming conversion, and this procedure shall be repeated until
all of the shares of Registrable Securities and Other Shares which may be
included in the registration on behalf of the Holders and other selling
stockholders have been so allocated.

     2.   RIGHT OF FIRST REFUSAL TO PURCHASE EQUITY SECURITIES.

          2.1. PURCHASE RIGHT. If at any time the Company should desire to issue
any Equity Securities (as hereinafter defined) in a transaction not registered
under the Securities Act in reliance upon a claimed exemption thereunder, it
shall give the Investors the first right to purchase the Investors' pro rata
share (or any part thereof) of all of such privately offered Equity Securities
on the same terms as the Company is willing to sell such Equity Securities to
any other person (a "Purchase Right"). The Investors' pro rata share of the
Equity Securities shall be equal to that percentage of the outstanding Common
Stock of the Company beneficially owned by the Investors on the date hereof, or,
in the case of the holders of Series G Warrants, on the date of exercise of such
Series G Warrants; provided, however, that no holder of a Series G Warrant shall
have a Purchase Right prior to the exercise of such warrant. For purposes of
this Section 2, the outstanding Common Stock of the Company shall include (i)
outstanding shares of Common Stock, and (ii) shares of Common Stock issued or
issuable upon conversion of any then outstanding Preferred Stock of the Company.

          2.2. NOTICE OF INTENT TO SELL AND ISSUE Prior to any sale or issuance
by the Company of any Equity Securities, the Company shall notify each Investor
in writing of its intention to sell and issue such securities, setting forth the
terms under which it proposes to make such sale. Within twenty (20) days after
receipt of such notice, each Investor shall notify the Company whether the
Investor desires to exercise the option to purchase the Investor's pro rata
share (or any part thereof) of the Equity Securities so offered. In no event
shall the Investor be obligated to purchase any Equity Securities pursuant to
this Section 2, nor does the Investor make any representation or warranty that
it plans to do so.

          2.3. INVESTOR FAILURE TO PURCHASE. After termination of the twenty
(20) day period specified in Section 2.2 above, the Company may, during a period
of sixty (60) days following the end of such twenty (20) day period, sell and
issue such Equity Securities as to which the Investors do not indicate a desire
to purchase to another person as well as those additional shares of Equity
Securities it originally intended to issue to other persons, upon terms and
conditions no less favorable to the Company than those set forth in the notice
to the Investors. In the event the Company has not sold the Equity Securities,
or has not entered into an agreement to sell the Equity Securities, within said
sixty (60) day period, the Company shall not thereafter issue or sell any Equity
Securities without first offering such securities to the Investors in the manner
provided above.

                                       14
<Page>

          2.4. INVESTOR PURCHASE. If an Investor gives the Company notice that
the Investor desires to purchase any of the Equity Securities offered by the
Company, payment for the Equity Securities shall be by check or wire transfer
against delivery of the Equity Securities at the executive offices of the
Company within twenty (20) days after giving the Company such notice, or, if
later, the closing date for the sale of such Equity Securities. The Company
shall take all such action as may be required by any regulatory authority in
connection with the exercise by the Investor of the Purchase Right.

          2.5. EXCLUDED SECURITIES. The Purchase Right contained in this Section
2 shall not apply to the issuance by the Company of Equity Securities (i) to
employees, officers, directors or consultants of the Company when approved by
the Company's Board of Directors, (ii) as part of an acquisition by the Company
of all or substantially all of the assets or shares of another company or entity
whether through a merger, exchange, reorganization or the like, (iii) issued
upon conversion of the Preferred Shares, (iv) issued upon the exercise or
conversion of any of the warrants described in Section 1.1(b), (v) issued in
connection with any stock split, stock dividend, recapitalization or similar
event, (vi) issued in connection with any commercial debt or lease financing
transaction approved by the Company's Board of Directors, (vii) issued in
connection with research and development partnerships, licensing or
collaborative arrangements or other similar transactions approved by the
Company's Board of Directors or (viii) issued in connection with the IPO.

          2.6. TERMINATION. The Purchase Right shall terminate (a) as to any
Investor, when such Investor declines to exercise in full the purchase option
referenced in Section 2.2 above unless the Company requests in writing that such
Investor not exercise such purchase option in full, and (b) as to all Investors,
upon the closing of the IPO.

          2.7. EQUITY SECURITIES. The term "Equity Securities" shall mean (i)
Common Stock and rights, options or warrants to purchase Common Stock, (ii) any
security other than Common Stock having voting rights in the election of the
Board of Directors, not contingent upon a failure to pay dividends, (iii) any
security convertible into or exchangeable for any of the foregoing, and (iv) any
agreement or commitment to issue any of the foregoing.

          2.8. ASSIGNMENT OF PURCHASE RIGHT. A Holder shall have the right to
assign the Purchase Right to an affiliate of the Investor or to any transferee
of at least thirty percent (30%) of such Holder's Registrable Securities (as
adjusted for stock splits, stock dividends, recapitalizations and like events);
provided, however, that such Holder shall retain its Purchase Right with respect
to the portion of Registrable Securities retained by such Holder in the event of
transfers of less than one hundred percent (100%) of such Holder's Registrable
Securities. For the purposes of this Section 2, an "affiliate" shall mean any
partner or shareholder of the Investor or any person or entity that directly or
indirectly through one or more intermediaries controls or is controlled by or is
under common control with the Investor.

     3.   GENERAL.

          3.1. WAIVERS AND AMENDMENTS. With the written consent of the record or
beneficial holders of at least sixty-six and two-thirds (66 2/3 %) of the
Registrable Securities, the obligations of the Company and the rights of the
other parties under this agreement may be

                                       15
<Page>

waived (either generally or in a particular instance, either retroactively or
prospectively, and either for a specified period of time or indefinitely), and
with the same consent the Company, when authorized by resolution of its Board of
Directors, may enter into a supplementary agreement for the purpose of adding
any provisions to or changing in any manner or eliminating any of the provisions
of this Agreement; provided, however, that no such modification, amendment or
waiver shall reduce the aforesaid percentage of Registrable Securities without
the consent of all of the Holders of the Registrable Securities; provided
further that in the event that such modification, amendment or waiver shall
adversely affect the rights and/or obligations of one particular series of the
Preferred Stock of the Company in a different manner than the other series of
the Preferred Stock of the Company, then such modification, amendment or waiver
shall also require the written consent or approval of the majority of the
Registrable Securities comprising such adversely affected series. Upon the
effectuation of each such waiver, consent, agreement of amendment or
modification, the Company shall promptly give written notice thereof to the
record holders of the Registrable Securities who have not previously consented
thereto in writing. This Agreement or any provision hereof may be changed,
waived, discharged or terminated only by a statement in writing signed by the
party against which enforcement of the change, waiver, discharge or termination
is sought, except to the extent provided in this Section 3.1.

          3.2. GOVERNING LAW. This Agreement shall be governed in all respects
by the laws of the State of California as such laws are applied to agreements
between California residents entered into and to be performed entirely within
California.

          3.3. SUCCESSORS AND ASSIGNS. Except as otherwise expressly provided
herein, the provisions hereof shall inure to the benefit of, and be binding
upon, the successors, assigns, heirs, executors and administrators of the
parties hereto.

          3.4. ENTIRE AGREEMENT. Except as set forth below, this Agreement and
the other documents delivered pursuant hereto and, with respect to the holders
of Series G Stock or Series G Warrants, the Merger Agreement and the documents
delivered pursuant thereto, constitute the full and entire understanding and
agreement between the parties with regard to the subjects hereof and thereof,
and this Agreement shall supersede and cancel all prior agreements between the
parties hereto with regard to the subject matter hereof.

          3.5. NOTICES, ETC. All notices and other communications required or
permitted hereunder shall be in writing and shall be delivered effective (i)
upon personal delivery, (ii) one business day after delivery to a reputable
overnight courier service, (iii) upon machine confirmed facsimile transmittal or
(iv) upon receipt if mailed by first class mail, postage prepaid, certified or
registered mail, return receipt requested (a) if to the Investors, at the
addresses as set forth in the Company's records, or at such other addresses as
any Investors shall have furnished to the Company in writing, or (b) if to the
Company, at 11494 Sorrento Valley Road, San Diego, CA 92121, Attn.: Chief
Executive Officer, or at such other address as the Company shall have furnished
to the Investors in writing.

          3.6. SEVERABILITY. If any provision of this Agreement, or the
application thereof, is for any reason and to any extent determined by a court
of competent jurisdiction to be invalid or unenforceable, the remainder of this
Agreement and the application of such provision

                                       16
<Page>

to other persons or circumstances will be interpreted so as best to reasonably
effect the intent of the parties hereto. The parties agree to use their best
efforts to replace such void or unenforceable provision of this Agreement with a
valid and enforceable provision which will achieve, to the extent greatest
possible, the economic, business and other purposes of the void or unenforceable
provision.

          3.7. TITLES AND SUBTITLES. The titles of the sections of this
Agreement are for convenience of reference only and are not to be considered in
construing this Agreement.

          3.8. COUNTERPARTS. This Agreement may be executed in any number of
counterparts, each of which shall be an original, but all of which together
shall constitute one instrument.

          3.9. NO INCONSISTENT AGREEMENTS. The Company will not enter into any
agreement with respect to it securities, which is inconsistent with or violates
the rights granted to the Holders of Registrable Securities in this Agreement.

          3.10. ADJUSTMENTS AFFECTING REGISTRABLE SECURITIES. The Company will
not take any action, or permit any change to occur, with respect to its
securities which would materially and adversely affect the ability of the
Holders of Registrable Securities to include such Registrable Securities in a
registration undertaken pursuant to this Agreement or which would materially and
adversely affect the marketability of such Registrable Securities in any such
registration.

            [THE REMAINDER OF THIS PAGE IS INTENTIONALLY LEFT BLANK]

                                       17

<Page>

     IN WITNESS WHEREOF, the parties hereby have executed this Agreement on the
date first above written.

                                       "COMPANY"
                                       MITOKOR

                                       By:    /s/ Walter H. Moos
                                              ----------------------------------
                                              Walter H. Moos
                                              ----------------------------------
                                              (print name)

                                       Title: Chairman & CEO
                                              ----------------------------------

                                       18
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       MITOKOR PREFERRED STOCKHOLDERS:

                                       3i BIOSCIENCE INVESTMENT TRUST PLC
                                       By:  Hare & Co

                                       By:    /s/ James C. Blair
                                              ----------------------------------
                                              James C. Blair
                                              ----------------------------------
                                              (print name)

                                       Title: Attorney-in-Fact
                                              ----------------------------------

                                       ALTA CALIFORNIA PARTNERS, L.P.
                                       By:   Alta California Management
                                             Partners, LLC
                                       Its:  General Partner

                                       By:    /s/ Jean Deleage
                                              ----------------------------------
                                              Jean Deleage
                                              ----------------------------------
                                              (print name)

                                       Title: General Partner
                                              ----------------------------------

                                       ALTA EMBARCADERO PARTNERS, LLC

                                       By:    /s/ Elanie Walker
                                              ----------------------------------
                                              Under Power of Attorney

                                              Elaine Walker
                                              ----------------------------------
                                              (print name)

                                       Title: Under Power of Attorney
                                              ----------------------------------

                                       19
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       ASGARD VENTURES

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       BIOINVEST INC.

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       BIOTECHNOLOGY INVESTMENTS LIMITED

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       BIOTECHVEST, INC.

                                       By:    /s/ Martin Pajor
                                              ----------------------------------
                                              Martin Pajor
                                              ----------------------------------
                                              (print name)

                                       Title: V.P.
                                              ----------------------------------

                                       20
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                        BIOTECHVEST, LLP

                        By:    /s/ Martin Pajor
                               ------------------------------------------------
                               Martin Pajor
                               ------------------------------------------------
                               (print name)

                        Title: V.P. of Biotechvest II, G.P. of Biotechvest L.P.
                               ------------------------------------------------

                        BIOTECHVEST, L.P.
                        By: Biotechvest II, Inc.

                        By:    /s/ Martin Pajor
                               ------------------------------------------------
                               Martin Pajor
                               ------------------------------------------------
                               (print name)

                        Title: V.P. of Biotechvest II, G.P. of Biotechvest L.P.
                               ------------------------------------------------

                        CHINA DEVELOPMENT INDUSTRIAL BANK, INC.

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

                               Benny T. Hu
                               ------------------------------------------------
                               (print name)

                        Title: President
                               ------------------------------------------------

                        CHIRON CORPORATION

                        By:    /s/ James R. Sulat
                               ------------------------------------------------
                               James R. Sulat
                               ------------------------------------------------
                               (print name)

                        Title: Chief Financial Officer
                               ------------------------------------------------

                                       21
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       DEAN P. CUPLIN AND CAMILLA KOCHENDERFER

                                       By:
                                              ----------------------------------
                                              Dean P. Cuplin

                                       By:
                                              ----------------------------------
                                              Camilla Kochenderfer

                                       ----------------------------------
                                       Kimberly Cuplin

                                       ----------------------------------
                                       Jason Cuplin

                                       DENYER FAMILY TRUST

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

                                              Paul Denyer
                                              ----------------------------------
                                              (print name)

                                       Title: Trustee
                                              ----------------------------------

                                       DOMAIN PARTNERS III, L.P.
                                       By:  One Palmer Square
                                            Associates III, L.P.

                                       By:    /s/ James C. Blair
                                              ----------------------------------
                                              James C. Blair
                                              ----------------------------------
                                              (print name)

                                       Title: General Partner
                                              ----------------------------------

                                       22
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       DP III ASSOCIATES, L.P.
                                       By:  One Palmer Square
                                            Associates III, L.P.

                                       By:    /s/ James C. Blair
                                              ----------------------------------
                                              James C. Blair
                                              ----------------------------------
                                              (print name)

                                       Title: General Partner
                                              ----------------------------------

                                       DONOVAN INVESTMENT COMPANY

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       EGM MEDICAL TECHNOLOGY FUND, L.P.

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       EGM MEDICAL TECHNOLOGY OFFSHORE FUND

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       23
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       EL DORADO C&L FUND, L.P.
                                       By:  El Dorado Venture Partners III
                                       Its:  General Partner

                                       By:    /s/ Gary Kalbach
                                              ----------------------------------
                                              Gary Kalbach
                                              ----------------------------------
                                              (print name)

                                       Title: General Partner
                                              ----------------------------------

                                       EL DORADO VENTURES, III, L. P.
                                       By:  El Dorado Venture Partners III
                                       Its:  General Partner

                                       By:    /s/ Gary Kalbach
                                              ----------------------------------
                                              Gary Kalbach
                                              ----------------------------------
                                              (print name)

                                       Title: General Partner
                                              ----------------------------------

                                       FIRST BIO VENTURE CAPITAL

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       FORWARD VENTURES II, L.P.
                                       By:  Forward II Associates, L.P.

                                       By:    /s/ Standish M. Fleming
                                              ----------------------------------

                                              Standish M. Fleming
                                              ----------------------------------
                                              (print name)

                                       Title: General Partner
                                              ----------------------------------

                                       24
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       FORWARD VENTURES III, L.P.
                                       By:  Forward III Associates, L.L.C.

                                       By:    /s/ Standish Fleming
                                              ----------------------------------
                                              Standish Fleming
                                              ----------------------------------
                                              (print name)

                                       Title: Managing Member
                                              ----------------------------------

                                       FORWARD VENTURES III
                                       INSTITUTIONAL PARTNERS, L.P.
                                       By:  Forward III Associates, L.L.C.

                                       By:    /s/ Standish Fleming
                                              ----------------------------------
                                              Standish Fleming
                                              ----------------------------------
                                              (print name)

                                       Title: Managing Member
                                              ----------------------------------

                                       FORWARD VENTURES IV, L.P.

                                       By:    /s/ Standish Fleming
                                              ----------------------------------
                                              Standish Fleming
                                              ----------------------------------
                                              (print name)

                                       Title: Managing Member
                                              ----------------------------------

                                       FORWARD VENTURES IV B, L.P.

                                       By:    /s/ Standish Fleming
                                              ----------------------------------
                                              Standish Fleming
                                              ----------------------------------
                                              (print name)

                                       Title:  Managing Member
                                              ----------------------------------

                                       25
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       -----------------------------------------
                                       Fredrick W. Field

                                       FRUIT OF THE LOOM, INC. SENIOR
                                       EXECUTIVE OFFICER DEFERRED
                                       COMPENSATION TRUST

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       FEDERATED KAUFMANN FUND

                                       By:   Federated Investment Management
                                             Company
                                       Its:  Attorney in Fact

                                              By: /s/ J. Christopher Donahue
                                                  ------------------------------
                                                  J. Christopher Donahue
                                                  CEO, CIO/COO

                                       LIAM BIOTECHVEST, LLC

                                       By:    /s/ Walter J. Sluzas
                                              ----------------------------------
                                              Walter J. Sluzas
                                              ----------------------------------
                                              (print name)

                                       Title: Member of the Administrative
                                              Committee of the Retirement
                                              Program of Farley Inc. Capital
                                              Member of Liam Biotechvest, LLC
                                              ----------------------------------

                                       26
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                              MDS HEALTH VENTURES (PC) INC.

                              By:    /s/ M. Calaghan   By: /s/ Graysanne Bedell
                                     ----------------      --------------------
                                     Michael Callaghan  /  Graysanne Bedell
                                     ------------------------------------------
                                     (print name)

                              Title: Vice-President    /   Assistant Secretary
                                     ------------------------------------------

                              MDS HEALTH VENTURES (TC) INC.

                              By:    /s/ Peter Winkley  By: /s/ Graysanne Bedell
                                     -----------------      --------------------
                                     Peter Winkley      /   Graysanne Bedell
                                     -------------------------------------------
                                     (print name)

                              Title: Vice-Pres & Contr. /   Assistant Secretary
                                     -------------------------------------------

                              NEUROSCIENCE PARTNERS LIMITED PARTNERSHIP
                              By:  MDS Associates - Neuroscience Inc.
                              Its:  General Partner

                              By:    /s/ M. Callaghan  / By: /s/ Graysanne Bedel
                                     ----------------        -------------------
                                     Michael Callaghan /     Graysanne Bedel
                                     -------------------------------------------
                                     (print name)

                              Title: Vice-President    /     Assistant Secretary
                                     -------------------------------------------

                              ORBITEX HEALTH & BIOTECHNOLOGY FUND, 2V1I

                              By:    /s/ Robert Youree
                                     ----------------------------------
                                     Robert Youree
                                     ----------------------------------
                                     (print name)

                              Title: Chief Operating Officer
                                     ----------------------------------

                                       27
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       POPOVER & CO.

                                       By:    /s/ Robert Youree
                                              ----------------------------------
                                              Robert Youree
                                              ----------------------------------
                                              (print name)

                                       Title: Chief Operating Officer
                                              ----------------------------------

                                       -----------------------------------------
                                       Mark Pentopoulos

                                       PFIZER, INC.

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       -----------------------------------------
                                       Peter Preuss

                                       -----------------------------------------
                                       Kellie Seringer

                                       28
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                  SENTRON MEDICAL, INC.

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

                                         ----------------------------------
                                         (print name)

                                  Title:
                                         ----------------------------------

                                  C.V. SOFINNOVA VENTURES PARTNERS III

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

                                         ----------------------------------
                                         (print name)

                                  Title:
                                         ----------------------------------

                                  SORRENTO GROWTH PARTNERS I, L.P.
                                  By:   Sorrento Equity Growth Partners I, L.P.,
                                  Its:  General Partner
                                  By:   Sorrento Growth, Inc.
                                  Its:  General Partner

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

                                         Robert M. Jaffe
                                         ----------------------------------
                                         (print name)

                                  Title: President
                                         ----------------------------------

                                  SORRENTO MITOKOR, a General Partnership

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

                                         ----------------------------------
                                         (print name)

                                  Title:
                                         ----------------------------------

                                       29
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       SORRENTO VENTURES III, L.P.
                                       By:   Sorrento Equity Partners III, L.P.
                                       Its:  General Partner
                                       By:   Sorrento Associates, Inc.
                                       Its:  General Partner

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

                                              Robert M. Jaffe
                                              ----------------------------------
                                              (print name)

                                       Title: President
                                              ----------------------------------

                                       SORRENTO VENTURES CE, L.P.
                                       By:   Sorrento Equity Partners III, L.P.
                                       Its:  General Partner
                                       By:   Sorrento Associates, Inc.
                                       Its:  General Partner

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

                                              Robert M. Jaffe
                                              ----------------------------------
                                              (print name)

                                       Title: President
                                              ----------------------------------

                                       S.R. ONE, LIMITED

                                       By:    /s/ R.J. Whitaker
                                              ----------------------------------
                                              R.J. Whitaker
                                              ----------------------------------
                                              (print name)

                                       Title: Vice President
                                              ----------------------------------

                                       30
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       THORNER VENTURES

                                       By:    /s/ Tom Thorner
                                              ----------------------------------
                                              Tom Thorner
                                              ----------------------------------
                                              (print name)

                                      Title:  Managing General Partner
                                              ----------------------------------

                                       MMC/GATX PARTNERSHIP NO. 1
                                       By: GATX CAPITAL CORP.
                                       Its:  General Partner

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       SILICON VALLEY BANC SHARES

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       31
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       THE ALDEN FOUNDATION

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       MARK BLACKMAN AND LINDA BLACKMAN

                                       By:
                                              ----------------------------------
                                              Mark Blackman, M.D.

                                       By:
                                              ----------------------------------
                                              Linda Blackman

                                       BLISS, GOUVERNEUR & ASSOCIATES, INC.

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       BOHEMOND CORPORATION

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       32
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       BRADLEY RESOURCES COMPANY

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       FANNY NIVES GRANTOR UNITRUST

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       FIRST TYME INVESTMENTS, INC.

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       WILLIAM K. FRASER & BONNIE JUNE
                                       GAUTREAU, JTWROS

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       33
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       ALAN GELBAND DEFINED TRUST

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       PAUL F. GLENN REVOCABLE TRUST

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       GUARANTEE & TRUST CO. TTEE
                                       F/B/O KENNETH LEVI

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       DELAWARE CHARTER GUARANTEE &
                                       TRUST COMPANY TTEE FBO:
                                       GEORGE A. ZAZANIS IRA ROLLOVER

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       34
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       JASON FAMILY TRUST DATED 12/22/82

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       JOSEPH BERLAND REVOCABLE LIVING TRUST

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       KAMCO SUPPLY CORP.

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       LAWRENCE KAPLAN AND HELAINE KAPLAN

                                       By:
                                              ----------------------------------
                                              Lawrence Kaplan

                                       By:
                                              ----------------------------------
                                              Helaine Kaplan

                                       35
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       JOHN D. LANE REVOCABLE LIVING
                                       TRUST DATED 9/14/89

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       MDS NEUROSCIENCE

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       MOONSHINE INVESTMENTS, INC.

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       PACIFIC HOLDINGS LTD.

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       36
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       RICHARD J. ROSENSTOCK REV. LIVING
                                       TRUST, R.J. ROSENSTOCK TRUSTEE,
                                       DTD 3/5/96

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       MICHAEL & LESLIE SILVERSTEIN, JTWROS

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       SECOND TYME INVESTMENTS, INC.

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       TRANSTIME, INC.

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

                                              ----------------------------------
                                              (print name)

                                       Title:
                                              ----------------------------------

                                       37
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       -----------------------------------------
                                       Janet Tweed Arkush

                                       -----------------------------------------
                                       John H. Baillie

                                       -----------------------------------------
                                       Victoria Bellport

                                       -----------------------------------------
                                       Richard Berger

                                       -----------------------------------------
                                       Craig Bloom

                                       -----------------------------------------
                                       Robert B. Brand

                                       -----------------------------------------
                                       George Hugh Brandon

                                       -----------------------------------------
                                       Anthony P. Brenner

                                       -----------------------------------------
                                       James Cane

                                       -----------------------------------------
                                       Nick Cane

                                       -----------------------------------------
                                       David Clemmons, Ph.D.

                                       38
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       -----------------------------------------
                                       Bruce Cohen

                                       -----------------------------------------
                                       Donna B. Cohen

                                       -----------------------------------------
                                       Douglas Covey, Ph.D.

                                       -----------------------------------------
                                       Ron Crosthwaite

                                       -----------------------------------------
                                       John Curry

                                       -----------------------------------------
                                       Alfred E. D'Ancona

                                       -----------------------------------------
                                       Frank D. DeMasi

                                       -----------------------------------------
                                       Frank Dunlop

                                       -----------------------------------------
                                       Gary Frashier

                                       -----------------------------------------
                                       Jeff Freed, M.D.

                                       -----------------------------------------
                                       Alan Gaines

                                       39
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       -----------------------------------------
                                       Alan Gelband

                                       -----------------------------------------
                                       Lawrence Goldstein

                                       -----------------------------------------
                                       R. Oscar Goldstein

                                       -----------------------------------------
                                       Ann Gordon

                                       -----------------------------------------
                                       Katherine Gordon

                                       -----------------------------------------
                                       Theodore J. Gordon

                                       -----------------------------------------
                                       Theresa Greunberg

                                       -----------------------------------------
                                       Levy Guar

                                       -----------------------------------------
                                       Zazanis Guar

                                       -----------------------------------------
                                       Shlomo Hadari

                                       -----------------------------------------
                                       S. Mitchell Harman, M.D.

                                       40
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       -----------------------------------------
                                       F. Donald Hudson

                                       -----------------------------------------
                                       Patricia B. Jackson

                                       -----------------------------------------
                                       Mark Jason

                                       -----------------------------------------
                                       Muncy Jason

                                       -----------------------------------------
                                       Robert B. Jason

                                       -----------------------------------------
                                       Roselyn H. Jason

                                       -----------------------------------------
                                       Barry Klein

                                       -----------------------------------------
                                       Anne Klibanski, M.D.

                                       -----------------------------------------
                                       Bruce Kurchack

                                       -----------------------------------------
                                       Philip Landfield, Ph.D.

                                       -----------------------------------------
                                       Robert Leonard

                                       41
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       -----------------------------------------
                                       John Lutri

                                       -----------------------------------------
                                       Thomas Lutri

                                       -----------------------------------------
                                       George Masters

                                       -----------------------------------------
                                       John M. McMahon

                                       -----------------------------------------
                                       Pat Moran

                                       -----------------------------------------
                                       Carolyn Mugar

                                       -----------------------------------------
                                       Alecia Nelson

                                       -----------------------------------------
                                       James Nelson, Ph.D.

                                       -----------------------------------------
                                       Edmund O'Donnell

                                       -----------------------------------------
                                       Jeff Perkell

                                       -----------------------------------------
                                       Norman Perlmutter

                                       42
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       -----------------------------------------
                                       Anthony L. Poger

                                       -----------------------------------------
                                       Anne Rose, Ph.D.

                                       -----------------------------------------
                                       Martine Rothblatt

                                       -----------------------------------------
                                       Christopher Saldivar

                                       -----------------------------------------
                                       Judith M. Segall, Ph.D.

                                       -----------------------------------------
                                       Paul E. Segall, Ph.D.

                                       -----------------------------------------
                                       Jacqueline Shafiroff

                                       -----------------------------------------
                                       Patricia Silver

                                       -----------------------------------------
                                       James Simpkins, Ph.D.

                                       -----------------------------------------
                                       William Sonntag, Ph.D.

                                       -----------------------------------------
                                       Hal Sternberg, Ph.D.

                                       43
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       -----------------------------------------
                                       Chaim Topol

                                       -----------------------------------------
                                       Barry Unger

                                       -----------------------------------------
                                       Harold D. Waitz

                                       -----------------------------------------
                                       Donald Weise

                                       -----------------------------------------
                                       Phyllis Wise, Ph.D.

                                       44
<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       Sofinnova Ventures, Inc.
                                       -----------------------------------------
                                       (Name of Investor)

                                       /s/ Michael Powell
                                       -----------------------------------------
                                       (Signature)

                                       By: Michael Powell
                                           -----------------------------------
                                           (Printed Name of Signatory)

                                       Title: Managing Director
                                             -----------------------------------

                                       45

<Page>
                           COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                   GCWF INVESTMENT PARTNERS II

                                   By:  GCWF INVESTMENTS LLC
                                   Its: Managing Partner

                                   /s/ Robert Ayling
                                   -----------------------------------------
                                   (Signature)

                                   By:    Robert Ayling
                                          ----------------------------------

                                   Title: Vice President
                                          ----------------------------------

                                       46

<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                       Palladian Opportunity Fund LLC
                                       -----------------------------------------
                                       (Name of Investor)

                                       /s/ Robert L. Chender
                                       -----------------------------------------
                                       (Signature)

                                       By: Robert L. Chender
                                           -----------------------------------
                                           (Printed Name of Signatory)

                                       Title: Managing Director
                                             -----------------------------------

                                       47

<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                  DRW Venture Partners LP
                                  ---------------------------------------------
                                  (Name of Investor)

                                  /s/ Mary Zimmer
                                  ---------------------------------------------
                                  (Signature)

                                  By: Mary Zimmer
                                      -----------------------------------------
                                      (Printed Name of Signatory)

                                  Title: Director of Finance and Administration,
                                         Dain Rauscher Wessels, a division of
                                         Dain Rauscher, Inc.
                                        ----------------------------------------

                                       48

<Page>

                          COUNTERPART SIGNATURE PAGE TO
                           INVESTORS' RIGHTS AGREEMENT

                                  RBC Dain Rauscher, Inc.
                                  ---------------------------------------------
                                  (Name of Investor)

                                  /s/ Mary Zimmer
                                  ---------------------------------------------
                                  (Signature)

                                  By: Mary Zimmer
                                      -----------------------------------------
                                      (Printed Name of Signatory)

                                  Title: Director of Finance and Administration,
                                         RBC Capital Markets, a division of
                                         Royal Bank of Canada and an affiliate
                                         of RBC Dain Rauscher, Inc.
                                        ----------------------------------------

                                       49

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