<PAGE>   1

                                                                   EXHIBIT 10.16


        THESE SECURITIES HAVE NOT BEEN REGISTERED UNDER THE SECURITIES
        ACT OF 1933 AS AMENDED, OR ANY STATE SECURITIES LAWS. THEY MAY
        NOT BE SOLD, OFFERED FOR SALE, PLEDGED, OR HYPOTHECATED IN THE
        ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT RELATED THERETO
        OR AN  OPINION  OF  COUNSEL  (WHICH  MAY BE  COMPANY  COUNSEL)
        REASONABLY  SATISFACTORY TO THE COMPANY THAT SUCH REGISTRATION
        IS NOT REQUIRED  UNDER THE SECURITIES ACT OF 1933, AS AMENDED,
        OR ANY APPLICABLE STATE SECURITIES LAWS.

                                WARRANT AGREEMENT

              To Purchase Shares of the Series A Preferred Stock of

                                      IRORI

               Dated as of February 9, 1996 (the "Effective Date")


        WHEREAS, IRORI, Inc., a California corporation (the "Company") has
entered into a Master Lease Agreement dated as of February 9, 1996, Equipment
Schedule No. VL-1 dated as of February 9, 1996, and related Summary Equipment
Schedules (collectively, the "Leases") with Comdisco, Inc., a Delaware
corporation (the "Warrantholder"); and

        WHEREAS, the Company desires to grant to Warrantholder, in consideration
for such Leases, the right to purchase shares of its Series A Preferred Stock;

        NOW, THEREFORE, in consideration of the Warrantholder executing and
delivering such Leases and in consideration of mutual covenants and agreements
contained herein, the Company and Warrantholder agree as follows:

1. GRANT OF THE RIGHT TO PURCHASE PREFERRED STOCK.

The Company hereby grants to the Warrantholder, and the Warrantholder is
entitled, upon the terms and subject to the conditions hereinafter set forth, to
subscribe to and purchase, from the Company, 9,700 fully paid and non-assessable
shares of the Company's Series A Preferred Stock ("Preferred Stock") at a
purchase price of $2.00 per share (the "Exercise Price"). The number and
purchase price of such shares are subject to adjustment as provided in Section 8
hereof.

If all of the Preferred Stock is converted into shares of Common Stock in
connection with a registration of the Company's Common Stock under the
Securities Act of 1933, as amended, then this Warrant shall automatically become
exercisable for that number of shares of Common Stock equal to the number of
shares of Common Stock that would have been received if this Warrant had been
exercised in full and the shares of Preferred Stock received thereupon had been
simultaneously converted into shares of Common Stock immediately prior to such
event, and the Exercise Price shall automatically be adjusted to equal the
amount obtained by dividing (i) the aggregate Exercise Price of the shares of
Preferred Stock for which this Warrant was exercisable immediately prior to such
conversion, by (ii) the number of shares of Common Stock for which this Warrant
is exercisable immediately after such conversion.

2. TERM OF THE WARRANT AGREEMENT.

Except as otherwise provided for herein, the term of this Warrant Agreement and
the right to purchase Preferred Stock as granted herein shall commence on the
Effective Date and shall be exercisable for a period of (i) ten (10) years or
(ii) five (5) years from the effective date of the Company's initial public
offering, whichever is longer.



                                      -1-
<PAGE>   2

3. EXERCISE OF THE PURCHASE RIGHTS.

The purchase rights set forth in this Warrant Agreement are exercisable by the
Warrantholder, in whole or in part, at any time, or from time to time, prior to
the expiration of the term set forth in Section 2 above, by tendering to the
Company at its principal office a notice of exercise in the form attached hereto
as Exhibit I (the "Notice of Exercise"), duly completed and executed. Promptly
upon receipt of the Notice of Exercise and the payment of the purchase price in
accordance with the terms set forth below, and in no event later than twenty-one
(21) days thereafter, the Company shall issue to the Warrantholder a certificate
for the number of shares of Preferred Stock purchased and shall execute the
acknowledgment of exercise in the form attached hereto as Exhibit II (the
"Acknowledgment of Exercise") indicating the number of shares which remain
subject to future purchases, if any.

The Exercise Price may be paid at the Warrantholder's election either (i) by
cash or check, or (ii) by surrender of Warrants ("Net Issuance") as determined
below. If the Warrantholder elects the Net Issuance method, the Company will
issue Preferred Stock in accordance with the following formula:

                X = Y(A-B)
                    -----
                      A

Where:          X =  the number of shares of Preferred Stock to be issued
                     to the Warrantholder.

                Y =  the number of shares of Preferred Stock requested to be
                     exercised under this Warrant Agreement.

                A =  the fair market value of one (1) share of Preferred Stock.

                B =  the Exercise Price.

For purposes of the above calculation, current fair market value of Preferred
Stock shall mean with respect to each share of Preferred Stock:

        (a) if the exercise is in connection with an initial public offering of
the Company's Common Stock, and if the Company's Registration Statement relating
to such public offering has been declared effective by the SEC, then the fair
market value per share shall be the product of (x) the initial "Price to Public"
specified in the final prospectus with respect to the offering and (y) the
number of shares of Common Stock into which each share of Preferred Stock is
convertible at the time of such exercise;

        (b) if this Warrant is exercised after, and not in connection with the
Company's initial public offering, and:

                (i) if traded on a securities exchange, the fair market value
        shall be deemed to be the product of (x) the average of the closing
        prices over a twenty-one (21) day period ending three days before the
        day the current fair market value of the securities is being determined
        and (y) the number of shares of Common Stock into which each share of
        Preferred Stock is convertible at the time of such exercise; or

                (ii) if actively traded over-the-counter, the fair market value
        shall be deemed to be the product of (x) the average of the closing bid
        and asked prices quoted on the NASDAQ system (or similar system) over
        the twenty-one (21) day period ending three days before the day the
        current fair market value of the securities is being determined and (y)
        the number of shares of Common Stock into which each share of Preferred
        Stock is convertible at the time of such exercise;

        (c) if at any time the Common Stock is not listed on any securities
exchange or quoted in the NASDAQ System or the over-the-counter market the
current fair market value of Preferred Stock shall be the product of (x) the
highest price per share which the Company could obtain from a willing buyer (not
a current employee or director) for shares of Common Stock sold by the Company,
from authorized but unissued shares, as determined in good faith by its Board of
Directors and (y) the number of shares of Common Stock into which each share of
Preferred Stock is convertible at the time of such exercise, unless the Company
shall become subject to a merger, acquisition or other



                                      -2-
<PAGE>   3

consolidation pursuant to which the Company is not the surviving party, in which
case the fair market value of Preferred Stock shall be deemed to be the value
received by the holders of the Company's Preferred Stock on a common equivalent
basis pursuant to such merger or acquisition.

Upon partial exercise by either cash or Net Issuance, the Company shall promptly
issue an amended Warrant Agreement representing the remaining number of shares
purchasable hereunder. All other terms and conditions of such amended Warrant
Agreement shall be identical to those contained herein, including, but not
limited to the Effective Date hereof.

4. RESERVATION OF SHARES.

        (a) Authorization and Reservation of Shares. During the term of this
Warrant Agreement, the Company will at all times have authorized and reserved a
sufficient number of shares of its Preferred Stock to provide for the exercise
of the rights to purchase Preferred Stock as provided for herein.

        (b) Registration or Listing. If any shares of Preferred Stock required
to be reserved hereunder require registration with or approval of any
governmental authority under any Federal or State law (other than any
registration under the 1933 Act, as then in effect, or any similar Federal
statute then enforced, or any state securities law, required by reason of any
transfer involved in such conversion), or listing on any domestic securities
exchange, before such shares may be issued upon conversion, the Company will, at
its expense and as expeditiously as possible, use its best efforts to cause such
shares to be duly registered, listed or approved for listing on such domestic
securities exchange, as the case may be.

5. NO FRACTIONAL SHARES OR SCRIP.

No fractional shares or scrip representing fractional shares shall be issued
upon the exercise of the Warrant, but in lieu of such fractional shares the
Company shall make a cash payment therefor upon the basis of the Exercise Price
then in effect.

6. NO RIGHTS AS SHAREHOLDER.

This Warrant Agreement does not entitle the Warrantholder to any voting rights
or other rights as a shareholder of the Company prior to the exercise of the
Warrant.

7. WARRANTHOLDER REGISTRY.

The Company shall maintain a registry showing the name and address of the
registered holder of this Warrant Agreement.

8. ADJUSTMENT RIGHTS.

The purchase price per share and the number of shares of Preferred Stock
purchasable hereunder are subject to adjustment, as follows:

        (a) Merger and Sale of Assets. If at any time there shall be a capital
reorganization of the shares of the Company's stock (other than a combination,
reclassification, exchange or subdivision of shares otherwise provided for
herein), or a merger or consolidation of the Company with or into another
corporation when the Company is not the surviving corporation, or the sale of
all or substantially all of the Company's properties and assets to any other
person (hereinafter referred to as a "Merger Event"), then, as a part of such
Merger Event, lawful provision shall be made so that the Warrantholder shall
thereafter be entitled to receive, upon exercise of the Warrant, the number of
shares of preferred stock or other securities of the successor corporation
resulting from such Merger Event, equivalent in value to that which would have
been issuable if Warrantholder had exercised this Warrant immediately prior to
the Merger Event. In any such case, appropriate adjustment (as determined in
good faith by the Company's Board of Directors) shall be made in the application
of the provisions of this Warrant Agreement with respect to the rights and
interest of the Warrantholder after the Merger Event to the end that the
provisions of this Warrant



                                      -3-
<PAGE>   4

Agreement (including adjustments of the Exercise Price and number of shares of
Preferred Stock purchasable) shall be applicable to the greatest extent
possible.

        (b) Reclassification of Shares. If the Company at any time shall, by
combination, reclassification, exchange or subdivision of securities or
otherwise, change any of the securities as to which purchase rights under this
Warrant Agreement exist into the same or a different number of securities of any
other class or classes, this Warrant Agreement shall thereafter represent the
right to acquire such number and kind of securities as would have been issuable
as the result of such change with respect to the securities which were subject
to the purchase rights under this Warrant Agreement immediately prior to such
combination, reclassification, exchange, subdivision or other change.

        (c) Subdivision or Combination of Shares. If the Company at any time
shall combine or subdivide its Preferred Stock, the Exercise Price shall be
proportionately decreased in the case of a subdivision, or proportionately
increased in the case of a combination.

        (d) Stock Dividends. If the Company at any time shall pay a dividend
payable in, or make any other distribution (except any distribution specifically
provided for in the foregoing subsections (a) or (b)) of the Company's stock,
then the Exercise Price shall be adjusted, from and after the record date of
such dividend or distribution, to that price determined by multiplying the
Exercise Price in effect immediately prior to such record date by a fraction (i)
the numerator of which shall be the total number of all shares of the Company's
stock outstanding immediately prior to such dividend or distribution, and (ii)
the denominator of which shall be the total number of all shares of the
Company's stock outstanding immediately after such dividend or distribution. The
Warrantholder shall thereafter be entitled to purchase, at the Exercise Price
resulting from such adjustment the number of shares of Preferred Stock
(calculated to the nearest whole share) obtained by multiplying the Exercise
Price in effect immediately prior to such adjustment by the number of shares of
Preferred Stock issuable upon the exercise hereof immediately prior to such
adjustment and dividing the product thereof by the Exercise Price resulting from
such adjustment.

        (e) Antidilution Rights. Additional antidilution rights applicable to
the Preferred Stock purchasable hereunder are as set forth in the Company's
Amended and Restated Articles of Incorporation, as amended through the Effective
Date, a true and complete copy of which is attached hereto as Exhibit IV (the
"Charter"). The Company shall promptly provide the Warrantholder with any
restatement amendment, modification or waiver of the Charter. (f) Notice of
Adjustments. If: (i) the Company shall declare any dividend or distribution upon
its stock, whether in cash, property, stock or other securities; (ii) the
Company shall offer for subscription prorata to the holders of any class of its
Preferred or other convertible stock any additional shares of stock of any class
or other rights; (iii) there shall be any Merger Event; (iv) there shall be an
initial public offering, or (v) there shall be any voluntary dissolution,
liquidation or winding up of the Company; then, in connection with each such
event, the Company shall send to the Warrantholder: (A) at least twenty (20)
days' prior written notice of the date on which the books of the Company shall
close or a record shall be taken for such dividend, distribution, subscription
rights (specifying the date on which the holders of Preferred Stock shall be
entitled thereto) or for determining rights to vote in respect of such Merger
Event, dissolution, liquidation or winding up; (B) in the case of any such
Merger Event, dissolution, liquidation or winding up, at least twenty (20) days'
prior written notice of the date when the same shall take place (and specifying
the date on which the holders of Preferred Stock shall be entitled to exchange
their Preferred Stock for securities or other property deliverable upon such
Merger Event, dissolution, liquidation or winding up); and (C) in the case of a
public offering, the Company shall give the Warrantholder at least twenty (20)
days written notice prior to the effective date hereof.

        Each such written notice shall set forth, in reasonable detail, (i) the
event requiring the adjustment, (ii) the amount of the adjustment, (iii) the
method by which such adjustment was calculated, (iv) the Exercise Price, and (V)
the number of shares subject to purchase hereunder after giving effect to such
adjustment and shall be given by first class mail, postage prepaid, addressed to
the Warrantholder, at the address as shown on the books of the Company.

        (g) Timely Notice. Failure to timely provide such notice required by
subsection (f) above shall entitle Warrantholder to retain the benefit of the
applicable notice period notwithstanding anything to the contrary contained in
any insufficient notice received by Warrantholder. The notice period shall begin
on the date Warrantholder actually receives a written notice containing all the
information specified above.



                                      -4-
<PAGE>   5

9. REPRESENTATIONS, WARRANTIES AND COVENANTS OF THE COMPANY.

        (a) Reservation of Preferred Stock. The Preferred Stock issuable upon
exercise of the Warrantholder's rights has been duly and validly reserved and,
when issued in accordance with the provisions of this Warrant Agreement, will be
validly issued, fully paid and non-assessable, and will be free of any taxes,
liens, charges or encumbrances of any nature whatsoever; provided, however, that
the Preferred Stock issuable pursuant to this Warrant Agreement may be subject
to restrictions on transfer under state and/or Federal securities laws. The
Company has made available to the Warrantholder true, correct and complete
copies of its Charter and Bylaws, as amended. The issuance of certificates for
shares of Preferred Stock upon exercise of the Warrant Agreement shall be made
without charge to the Warrantholder for any issuance tax in respect thereof, or
other cost incurred by the Company in connection with such exercise and the
related issuance of shares of Preferred Stock. The Company shall not be required
to pay any tax which may be payable in respect of any transfer involved and the
issuance and delivery of any certificate in a name other than that of the
Warrantholder.

        (b) Due Authority. The execution and delivery by the Company of this
Warrant Agreement and the performance of all obligations of the Company
hereunder, including the issuance to Warrantholder of the right to acquire the
shares of Preferred Stock, have been duly authorized by all necessary corporate
action on the part of the Company, and the Leases and this Warrant Agreement are
not inconsistent with the Company's Charter or Bylaws, do not contravene any law
or governmental rule, regulation or order applicable to it, do not and will not
contravene any provision of, or constitute a default under, any indenture,
mortgage, contract or other instrument to which it is a party or by which it is
bound, and the Leases and this Warrant Agreement constitute legal, valid and
binding agreements of the Company, enforceable in accordance with their
respective terms.

        (c) Consents and Approvals. No consent or approval of, giving of notice
to, registration with, or taking of any other action in respect of any state,
Federal or other governmental authority or agency is required with respect to
the execution, delivery and performance by the Company of its obligations under
this Warrant Agreement, except for the filing of notices pursuant to Regulation
D under the 1933 Act and any filing required by applicable state securities law,
which filings will be effective by the time required thereby.

        (d) Issued Securities. All issued and outstanding shares of Common
Stock, Preferred Stock or any other securities of the Company have been duly
authorized and validly issued and are fully paid and nonassessable. All
outstanding shares of Common Stock, Preferred Stock and any other securities
were issued in full compliance with all Federal and state securities laws. In
addition:

                (i) The authorized capital of the Company consists of (A)
        10,000,000 shares of Common Stock, of which 730,000 shares are issued
        and outstanding, and (B) 1,750,000 shares of preferred stock, of which
        750,000 shares are issued and outstanding and are convertible into
        750,000 shares of Common Stock at $2.00 per share.

                (ii) The Company has reserved (A) 287,000 of Common Stock for
        issuance under its Stock Option Plans. The Company currently has no
        options outstanding under it Nonqualified Stock Option Plan, and options
        for 73,100 shares outstanding at an average price of $0.20 per share
        under its Incentive Stock Option Plan. In addition the Company has a
        warrant to Enterprise Partners III, LP for the issuance of 150,000
        shares of Common Stock at an exercise price of $0.01 per share. There
        are no other options, warrants, conversion privileges or other rights
        presently outstanding to purchase or otherwise acquire any authorized
        but unissued shares of the Company's capital stock or other securities
        of the Company.

                (iii) Except as set forth in the Investors' Rights Agreement
        dated as of October 19, 1995 ("Investors' Rights Agreement"), no
        shareholder of the Company has preemptive rights to purchase new
        issuances of the Company's capital stock.

        (e) Insurance. The Company has in full force and effect insurance
policies, with extended coverage, insuring the Company and its property and
business against such losses and risks, and in such amounts, as are customary
for corporations engaged in a similar business and similarly situated and as
otherwise may be required pursuant to the terms of any other contract or
agreement.



                                      -5-
<PAGE>   6

        (f) Other Commitments to Register Securities. Except as set forth in the
Investors' Rights Agreement, the Company is not, pursuant to the terms of any
other agreement currently in existence, under any obligation to register under
the 1933 Act any of its presently outstanding securities or any of its
securities which may hereafter be issued.

        (g) Exempt Transaction. Subject to the accuracy of the Warrantholder's
representations in Section 10 hereof, the issuance of the Preferred Stock upon
exercise of this Warrant will constitute a transaction exempt from (i) the
registration requirements of Section 5 of the 1933 Act in reliance upon Section
4(2) thereof, and (ii) the qualification requirements of the applicable state
securities laws.

        (h) Compliance with Rule 144. At the written request of the
Warrantholder, who proposes to sell Preferred Stock issuable upon the exercise
of the Warrant in compliance with Rule 144 promulgated by the Securities and
Exchange Commission, the Company shall furnish to the Warrantholder, within ten
days after receipt of such request, a written statement confirming the Company's
compliance with the filing requirements of the Securities and Exchange
Commission as set forth in such Rule, as such Rule may be amended from time to
time.

10. REPRESENTATIONS AND COVENANTS OF THE WARRANTHOLDER.

This Warrant Agreement has been entered into by the Company in reliance upon the
following representations and covenants of the Warrantholder:

        (a) Investment Purpose. The right to acquire Preferred Stock or the
Preferred Stock issuable upon exercise of the Warrantholder's rights contained
herein will be acquired for investment and not with a view to the sale or
distribution of any part thereof, and the Warrantholder has no present intention
of selling or engaging in any public distribution of the same except pursuant to
a registration or exemption.

        (b) Private Issue. The Warrantholder understands (i) that the Preferred
Stock issuable upon exercise of this Warrant is not registered under the 1933
Act or qualified under applicable state securities laws on the ground that the
issuance contemplated by this Warrant Agreement will be exempt from the
registration and qualifications requirements thereof, and (ii) that the
Company's reliance on such exemption is predicated on the representations set
forth in this Section 10.

        (c) Disposition of Warrantholder's Rights. In no event will the
Warrantholder make a disposition of any of its rights to acquire Preferred Stock
or Preferred Stock issuable upon exercise of such rights unless and until (i) it
shall have notified the Company of the proposed disposition, and (ii) if
requested by the Company, it shall have furnished the Company with an opinion of
counsel (which counsel may either be inside or outside counsel to the
Warrantholder) satisfactory to the Company and its counsel to the effect that
(A) appropriate action necessary for compliance with the 1933 Act has been
taken, or (B) an exemption from the registration requirements of the 1933 Act is
available. Notwithstanding the foregoing, the restrictions imposed upon the
transferability of any of its rights to acquire Preferred Stock or Preferred
Stock issuable on the exercise of such rights do not apply to transfers from the
beneficial owner of any of the aforementioned securities to its nominee or from
such nominee to its beneficial owner, and shall terminate as to any particular
share of Preferred Stock when (1) such security shall have been effectively
registered under the 1933 Act and sold by the holder thereof in accordance with
such registration or (2) such security shall have been sold without registration
in compliance with Rule 144 under the 1933 Act, or (3) a letter shall have been
issued to the Warrantholder at its request by the staff of the Securities and
Exchange Commission or a ruling shall have been issued to the Warrantholder at
its request by such Commission stating that no action shall be recommended by
such staff or taken by such Commission, as the case may be, if such security is
transferred without registration under the 1933 Act in accordance with the
conditions set forth in such letter or ruling and such letter or ruling
specifies that no subsequent restrictions on transfer are required. Whenever the
restrictions imposed hereunder shall terminate, as hereinabove provided, the
Warrantholder or holder of a share of Preferred Stock then outstanding as to
which such restrictions have terminated shall be entitled to receive from the
Company, without expense to such holder, one or more new certificates for the
Warrant or for such shares of Preferred Stock not bearing any restrictive
legend.

        (d) Financial Risk. The Warrantholder has such knowledge and experience
in financial and business matters as to be capable of evaluating the merits and
risks of its investment, and has the ability to bear the economic risks of its
investment.



                                      -6-
<PAGE>   7

        (e) Risk of No Registration. The Warrantholder understands that if the
Company does not register with the Securities and Exchange Commission pursuant
to Section 12 of the 1933 Act, or file reports pursuant to Section 15(d), of the
Securities Exchange Act of 1934 (the "1934 Act"), or if a registration statement
covering the securities under the 1933 Act is not in effect when it desires to
sell (i) the rights to purchase Preferred Stock pursuant to this Wan-ant
Agreement, or (ii) the Preferred Stock issuable upon exercise of the right to
purchase, it may be required to hold such securities for an indefinite period.
The Warrantholder also understands that any sale of its rights of the
Warrantholder to purchase Preferred Stock or Preferred Stock which might be made
by it in reliance upon Rule 144 under the 1933 Act may be made only in
accordance with the terms and conditions of that Rule.

        (f) Accredited Investor. Warrantholder is an "accredited investor"
within the meaning of the Securities and Exchange Rule 501 of Regulation D, as
presently in effect.

11. TRANSFERS. Subject to the terms and conditions contained in Section 10
hereof, this Wan-ant Agreement and all rights hereunder are transferable in
whole or in part by the Warrantholder and any successor transferee, provided,
however, in no event shall the number of transfers of the rights and interests
in all of the Warrants exceed three (3) transfers. The transfer shall be
recorded on the books of the Company upon receipt by the Company of a notice of
transfer in the form attached hereto as Exhibit III (the "Transfer Notice"), at
its principal offices and the payment to the Company of all transfer taxes and
other governmental charges imposed on such transfer.

12. MISCELLANEOUS.

        (a) Effective Date. The provisions of this Warrant Agreement shall be
construed and shall be given effect in all respects as if it had been executed
and delivered by the Company on the date hereof This Warrant Agreement shall be
binding upon any successors or assigns of the Company.

        (b) Attorney's Fees. In any litigation, arbitration or court proceeding
between the Company and the Warrantholder relating hereto, the prevailing party
shall be entitled to attorneys' fees and expenses and all costs of proceedings
incurred in enforcing this Warrant Agreement.

        (c) Governing Law. This Warrant Agreement shall be governed by and
construed for all purposes under and in accordance with the laws of the State of
Illinois.

        (d) Counterparts. This Warrant Agreement may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

        (e) Notices. Any notice required or permitted hereunder shall be given
in writing and shall be deemed effectively given upon personal delivery,
facsimile transmission (provided that the original is sent by personal delivery
or mail as hereinafter set forth) or seven (7) days after deposit in the United
States mail, by registered or certified mail, addressed (i) to the Warrantholder
at 6111 North River Road, Rosemont, Illinois 60018, attention: James Labe,
Venture Group, cc: Legal Department, attn: General Counsel, (and/or, if by
facsimile, (708) 518-5466 and (708)518-5088) and (ii) to the Company at 11025 N.
Torrey Pines Road Suite 100, La Jolla, California 92037, (and/or if by
facsimile, (619)546-3083) or at such other address as any such party may
subsequently designate by written notice to the other party.

        (f) Remedies. In the event of any default hereunder, the non-defaulting
party may proceed to protect and enforce its rights either by suit in equity
and/or by action at law, including but not limited to an action for damages as a
result of any such default, and/or an action for specific performance for any
default where Warrantholder will not have an adequate remedy at law and where
damages will not be readily ascertainable. The Company expressly agrees that it
shall not oppose an application by the Warrantholder or any other person
entitled to the benefit of this Agreement requiring specific performance of any
or all provisions hereof or enjoining the Company from continuing to commit any
such breach of this Agreement.

        (g) No Impairment of Rights. The Company will not, by amendment of its
Charter or through any other means, avoid or seek to avoid the observance or
performance of any of the terms of this Warrant, but will at all



                                      -7-
<PAGE>   8

times in good faith assist in the carrying out of all such terms and in the
taking of all such actions as may be necessary or appropriate in order to
protect the rights of the Warrantholder against impairment.

        (h) Survival. The representations, warranties, covenants and conditions
of the respective parties contained herein or made pursuant to this Warrant
Agreement shall survive the execution and delivery of this Warrant Agreement.

        (i) Severability. In the event any one or more of the provisions of this
Warrant Agreement shall for any reason be held invalid, illegal or
unenforceable, the remaining provisions of this Warrant Agreement shall be
unimpaired, and the invalid, illegal or unenforceable provision shall be
replaced by a mutually acceptable valid, legal and enforceable provision, which
comes closest to the intention of the parties underlying the invalid, illegal or
unenforceable provision.

        (j) Amendments. Any provision of this Warrant Agreement may be amended
by a written instrument signed by the Company and by the Warrantholder.

        (k) Additional Documents. The Company, upon execution of this Warrant
Agreement shall provide the Warrantholder with certified resolutions with
respect to the representations, warranties and covenants set forth in
subparagraphs (a) through (d), (f) and (g) of Section 9 above. If the purchase
price for the Leases referenced in the preamble of this Warrant Agreement
exceeds $1,000,000, the Company will also provide Warrantholder with an opinion
from the Company's counsel with respect to those same representations,
warranties and covenants. The Company shall also supply such other documents as
the Warrantholder may from time to time reasonably request.

IN WITNESS WHEREOF, the parties hereto have caused this Warrant Agreement to be
executed by its officers thereunto duly authorized as of the Effective Date.



                                     Company:  IRORI

                                     By: /s/  illegible
                                         ------------------------------

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

                                     Warrantholder: COMDISCO, INC.

                                     By: /s/  James P. Labe
                                         ------------------------------
                                         James P. Labe

                                     Title:  James P. Labe, President
                                           ----------------------------
                                             Venture Lease Division




                                      -8-
<PAGE>   9

                                    EXHIBIT I

                               NOTICE OF EXERCISE


To:___________________


(1)     The undersigned Warrantholder hereby elects to purchase _______ shares
        of the Series A Preferred Stock of Irori, pursuant to the terms of the
        Warrant Agreement dated the _______ day of _______________, 19__ (the
        "Warrant Agreement") between Irori and the Warrantholder, and tenders
        herewith payment of the purchase price for such shares in full, together
        with all applicable transfer taxes, if any.

(2)     In exercising its rights to purchase the Series A Preferred Stock of
        Irori _______________________________________, the undersigned hereby
        confirms and acknowledges the investment representations and warranties
        made in Section 10 of the Warrant Agreement.

(3)     Please issue a certificate or certificates representing said shares of
        Series A Preferred Stock in the name of the undersigned or in such other
        name as is specified below.




____________________________________
(Name)


____________________________________
(Address)

Warrantholder:  COMDISCO, INC.


By:_________________________________

Title:______________________________

Date:_______________________________





                                      -9-
<PAGE>   10

                                   EXHIBIT II

                           ACKNOWLEDGEMENT OF EXERCISE


        The undersigned ______________________________, hereby acknowledge
receipt of the "Notice of Exercise" from Comdisco, Inc., to purchase _____
shares of the Series A Preferred Stock of ____________________________________,
pursuant to the terms of the Warrant Agreement, and further acknowledges that
_______ shares remain subject to purchase under the terms of the Warrant
Agreement.



                                           Company:


                                           By:_________________________________

                                           Title:______________________________

                                           Date:_______________________________





                                      -10-
<PAGE>   11

                                   EXHIBIT III


                                 TRANSFER NOTICE


        (To transfer or assign the foregoing Warrant Agreement execute this form
and supply required information. Do not use this form to purchase shares.)

        FOR VALUE RECEIVED, the foregoing Warrant Agreement and all rights
evidenced thereby are hereby transferred and assigned to



____________________________________________________________
(Please Print)


whose address is____________________________________________

____________________________________________________________



                       Dated________________________________

                       Holder's Signature___________________

                       Holder's Address_____________________




Signature Guaranteed:_______________________________________


NOTE:   The signature to this Transfer Notice must correspond with the name as
        it appears on the face of the Warrant Agreement, without alteration or
        enlargement or any change whatever. Officers of corporations and those
        acting in a fiduciary or other representative capacity should file
        proper evidence of authority to assign the foregoing Warrant Agreement.







                                      -11-