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                                                                   EXHIBIT 10.21

                                                                  EXECUTION COPY



THESE SECURITIES HAVE NOT BEEN REGISTERED WITH THE UNITED STATES SECURITIES AND
EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE PURSUANT TO AN
EXEMPTION FROM REGISTRATION UNDER REGULATION D PROMULGATED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED (THE "ACT") OR OTHERWISE. THIS WARRANT SHALL NOT
CONSTITUTE AN OFFER TO SELL NOR A SOLICITATION OF AN OFFER TO BUY THE SECURITIES
IN ANY JURISDICTION IN WHICH SUCH OFFER OR SOLICITATION WOULD BE UNLAWFUL. THE
SECURITIES ARE "RESTRICTED" AND MAY NOT BE RESOLD OR TRANSFERRED EXCEPT AS
PERMITTED UNDER THE ACT PURSUANT TO REGISTRATION OR EXEMPTION THEREFROM.



                          COMMON STOCK PURCHASE WARRANT

No. PW1

              To Purchase Shares of $.001 Par Value Common Stock of

                                  ZYMETX, INC.

         THIS CERTIFIES that, for value received, Palladin Opportunity Fund, LLC
(the "INVESTOR") is entitled, upon the terms and subject to the conditions
hereinafter set forth, at any time on or after the date hereof and on or prior
to 5:00 p.m. New York City Time on October 12, 2005 (the "TERMINATION DATE"),
but not thereafter, to subscribe for and purchase from ZYMETX, INC., a Delaware
corporation (the "COMPANY"), 90,000 shares of Common Stock of the Company (the
"WARRANT SHARES"). The "EXERCISE PRICE" is $3.16875. The Exercise Price and the
number of shares for which the Warrant is exercisable shall be subject to
adjustment as provided herein. This Warrant is being issued in connection with
the Purchase Agreement dated October 13, 2000 (the "AGREEMENT") entered into
between the Company and the Investor.

1.       Title of Warrant. Prior to the expiration hereof and subject to
         compliance with applicable laws, this Warrant and all rights hereunder
         are transferable, in whole or in respect of the right to purchase any
         part of the Warrant Shares, at the office or agency of the Company by
         the holder hereof in person or by duly authorized attorney, upon
         surrender of this Warrant together with (a) the Assignment Form annexed
         hereto properly endorsed, and (b) any other documentation reasonably
         necessary to satisfy the Company that such transfer is in compliance
         with all applicable securities laws.

2.       Authorization of Shares. The Company covenants that all shares of
         Common Stock which may be issued upon the exercise of rights
         represented by this Warrant will, upon exercise of the rights
         represented by this Warrant and payment of the Exercise Price as set
         forth herein will be duly authorized, validly issued, fully paid and
         nonassessable and free from all taxes, liens and charges in respect of
         the issue thereof (other than taxes in respect of any transfer
         occurring contemporaneously with such issue or otherwise specified
         herein).



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3.       Exercise of Warrant.

(a)      Exercise of the purchase rights represented by this Warrant may be made
         at any time or times, in whole or in part before the close of business
         on the Termination Date, or such earlier date on which this Warrant may
         terminate as provided in paragraph 11 below, by the surrender on any
         business day of this Warrant and the Notice of Exercise annexed hereto
         duly completed and executed, at the principal office of the Company (or
         such other office or agency of the Company as it may designate by
         notice in writing to the registered holder hereof at the address of
         such holder appearing on the books of the Company), together with
         delivery to the Company by such holder of all certifications or
         documentation reasonably necessary to establish, to the satisfaction of
         the Company, that any such exercise has been undertaken in compliance
         with all applicable federal and state securities laws, and upon payment
         of the full Exercise Price of the shares thereby purchased; whereupon
         the holder of this Warrant shall be entitled to receive a certificate
         for the number of shares of Common Stock so purchased. Certificates for
         shares purchased hereunder shall be delivered to the holder hereof
         within three (3) Trading Days after the date on which this Warrant
         shall have been exercised as aforesaid. Payment of the Exercise Price
         of the shares shall be by certified check or cashier's check or by wire
         transfer (of same day funds) to an account designated by the Company in
         an amount equal to the Exercise Price multiplied by the number of
         shares being purchased.

(b)      Alternatively, the Warrant holder may exercise this Warrant, in whole
         or in part in a "cashless" or "net-issue" exercise by delivering to the
         offices of the Company or any transfer agent for the Common Stock this
         Warrant, together with a Notice of Exercise specifying the number of
         Warrant Shares to be delivered to such Warrant holder ("DELIVERABLE
         SHARES") and the number of Warrant Shares with respect to which this
         Warrant is being exercised ("EXERCISED SHARES").

         The number of Deliverable Shares shall be calculated as follows:

         # of Deliverable Shares = # of Exercised Shares
                      x Fair Market Value of Common Stock less Exercise Price
                      -------------------------------------------------------
                                Fair Market Value of Common Stock

         "FAIR MARKET VALUE" shall have the meaning specified in Section 13(c)

         In the event that the Warrant is not exercised in full, the number of
         Warrant Shares shall be reduced by the number of such Warrant Shares
         for which this Warrant is exercised and/or surrendered, and the
         Company, at its expense, shall within three (3) Trading Days issue and
         deliver to or upon the order of the Warrant holder a new Warrant of
         like tenor in the name of Warrant holder or such other name as Warrant
         holder (upon payment by Warrant holder of any applicable transfer
         taxes) may request, reflecting such adjusted Warrant Shares.

         All exercises will be deemed to occur as of the date of the Notice of
         Exercise, and certificates for shares of Common Stock purchased
         hereunder shall be delivered to the holder hereof within three (3)
         Trading Days after the date on which this Warrant shall



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         have been exercised as aforesaid. The Warrant holder may withdraw its
         Notice of Exercise under Section 3(a) or 3(b) at any time thereafter if
         the Company fails to timely deliver the applicable certificates to the
         Warrant holder as provided in this Agreement.

(c)      In lieu of delivering physical certificates representing the Common
         Stock issuable upon exercise, provided the Company's transfer agent is
         participating in the Depository Trust Company ("DTC") Fast Automated
         Securities Transfer ("FAST") program, upon request of the Warrant
         holder, the Company shall use its best efforts to cause its transfer
         agent to electronically transmit the Common Stock issuable upon
         exercise to the Warrant holder by crediting the account of Warrant
         holder's prime broker with DTC through its Deposit Withdrawal Agent
         Commission ("DWAC") system. The time periods for delivery described in
         the immediately preceding paragraph shall apply to the electronic
         transmittals described herein.

         The term "TRADING DAY" means (x) if the Common Stock is listed on the
         New York Stock Exchange or the American Stock Exchange, a day on which
         there is trading on such stock exchange, or (y) if the Common Stock is
         not listed on either of such stock exchanges but sale prices of the
         Common Stock are reported on an automated quotation system, a day on
         which trading is reported on the principal automated quotation system
         on which sales of the Common Stock are reported, or (z) if the
         foregoing provisions are inapplicable, a day on which quotations are
         reported by National Quotation Bureau Incorporated.

4.       No Fractional Shares or Scrip. No fractional shares or scrip
         representing fractional shares shall be issued upon the exercise of
         this Warrant.

5.       Charges, Taxes and Expenses. Issuance of certificates for shares of
         Common Stock upon the exercise of this Warrant shall be made without
         charge to the holder hereof for any issue or transfer tax or other
         incidental expense in respect of the issuance of such certificate, all
         of which taxes and expenses shall be paid by the Company, and such
         certificates shall be issued in the name of the holder of this Warrant
         or in such name or names as may be directed by the holder of this
         Warrant; provided, however, that in the event certificates for shares
         of Common Stock are to be issued in a name other than the name of the
         holder of this Warrant, this Warrant when surrendered for exercise
         shall be accompanied by the Assignment Form attached hereto duly
         executed by the holder hereof; and provided further, that the Company
         shall not be required to pay any tax or taxes which may be payable in
         respect of any transfer involved in the issuance of any Warrant
         certificates or any certificates for the Warrant Shares other than the
         issuance of a Warrant Certificate to the Investor in connection with
         the Investor's surrender of a Warrant Certificate upon the exercise of
         less than all of the Warrants evidenced thereby, and the Company shall
         not be required to issue or deliver such certificates unless or until
         the person or persons requesting the issuance thereof shall have paid
         to the Company the amount of such tax or shall have established to the
         satisfaction of the Company that such tax has been paid.



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6.       Closing of Books. The Company will at no time close its stockholder
         books or records in any manner which interferes with the timely
         exercise of this Warrant.

7.       No Rights as Stockholder until Exercise. Subject to Section 12 of this
         Warrant and the provisions of any other written agreement between the
         Company and the Investor, the Investor shall not be entitled to vote or
         receive dividends or be deemed the holder of Warrant Shares or any
         other securities of the Company that may at any time be issuable on the
         exercise hereof for any purpose, nor shall anything contained herein be
         construed to confer upon the Investor, as such, any of the rights of a
         stockholder of the Company or any right to vote for the election of
         directors or upon any matter submitted to stockholders at any meeting
         thereof, or to give or withhold consent to any corporate action
         (whether upon any recapitalization, issuance of stock, reclassification
         of stock, change of par value, or change of stock to no par value,
         consolidation, merger, conveyance or otherwise) or to receive notice of
         meetings, or to receive dividends or subscription rights or otherwise
         until the Warrant shall have been exercised as provided herein.
         However, at the time of the exercise of this Warrant pursuant to
         Section 3 hereof, the Warrant Shares so purchased hereunder shall be
         deemed to be issued to such holder as the record owner of such shares
         as of the close of business on the date on which this Warrant shall
         have been exercised.

8.       Assignment and Transfer of Warrant. This Warrant may be assigned in
         whole or in part by the surrender of this Warrant and the Assignment
         Form annexed hereto duly executed at the office of the Company (or such
         other office or agency of the Company as it may designate by notice in
         writing to the registered holder hereof at the address of such holder
         appearing on the books of the Company); provided, however, that this
         Warrant may not be resold or otherwise transferred except (i) in a
         transaction registered under the Securities Act of 1933, as amended
         (the "ACT"), or (ii) in a transaction pursuant to an exemption, if
         available, from registration under the Act and whereby, if requested by
         the Company, an opinion of counsel reasonably satisfactory to the
         Company is obtained by the holder of this Warrant to the effect that
         the transaction is so exempt.

9.       Loss, Theft, Destruction or Mutilation of Warrant. Upon receipt by the
         Company of evidence reasonably satisfactory to it of the loss, theft,
         destruction or mutilation of any Warrant or stock certificate
         representing the Warrant Shares, and in case of loss, theft or
         destruction, of indemnity reasonably satisfactory to it, and upon
         reimbursement to the Company of all reasonable expenses incidental
         thereto (and upon surrender and cancellation of such Warrant or stock
         certificate, if mutilated), the Company will make and deliver a new
         Warrant or stock certificate of like tenor and dated as of such receipt
         or cancellation, in lieu of this Warrant or such stock certificate.

10.      Saturdays, Sundays, Holidays, etc. If the last or appointed day for the
         taking of any action or the expiration of any right required or granted
         herein shall be a Saturday, Sunday or a legal holiday, then such action
         may be taken or such right may be exercised on the next succeeding day
         not a legal holiday.



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11.      Change in Control Transaction.

(a)      If at any time there occurs any Change in Control Transaction, the
         holder of this Warrant shall be entitled, at its sole option, to have
         the Company redeem this Warrant in whole or in part at the applicable
         Premium Redemption Price (as defined in the Registration Rights
         Agreement). Such holder shall be entitled to make such election at any
         time upon a Public Announcement of a pending, and up to ten (10) days
         after the effective date of a, Change in Control Transaction.

                  "CHANGE IN CONTROL TRANSACTION" shall mean the occurrence of
         (i) any consolidation or merger of the Company with or into any other
         corporation or other entity or person (whether or not the Company is
         the surviving corporation), or any other corporate reorganization or
         transaction or series of related transactions in which in excess of 50%
         of the Company's voting power is transferred through a merger,
         consolidation, tender offer or similar transaction; or (ii) any person
         (as defined in Section 13(d) of the Securities Exchange Act of 1934, as
         amended (the "EXCHANGE ACT")), together with its affiliates and
         associates (as such terms are defined in Rule 405 under the Act),
         beneficially owns or is deemed to beneficially own (as described in
         Rule 13d-3 under the Exchange Act without regard to the 60-day exercise
         period) in excess of 50% of the Company's voting power; (iii) there is
         a replacement of more than one-half of the members of the Company's
         Board of Directors which is not approved by those individuals who are
         members of the Company's Board of Directors on the date thereof; or
         (iv) in one or a series of related transactions there is a sale or
         transfer of all or substantially all of the assets of the Company,
         determined on a consolidated basis.

                  "PUBLIC ANNOUNCEMENT" shall mean any public filing with the
         Securities and Exchange Commission, any press release by either the
         Company or a third party or any other public statement, that announces
         a proposed transaction which, if consummated, would constitute a Change
         in Control Transaction.

(b)      If at any time there occurs a Public Announcement of a pending Change
         in Control Transaction in which the public stockholders of the Company
         are to receive consideration, a portion of which is capital stock or
         any security convertible into capital stock of another entity in
         exchange for shares of Common Stock ("CHANGE IN CONTROL
         CONSIDERATION"), then prompt provision shall be made in a manner
         reasonably acceptable to the holders so that each holder shall have the
         right (in addition to its other rights under this Warrant and the other
         Transaction Documents) following such Public Announcement to:

         (i) convert its Warrants into the Change in Control Consideration that
such holder would have been or would be entitled to receive had it exercised all
of its Warrants into Common Stock (notwithstanding any restrictions imposed upon
the holder pursuant to this Warrant, the Debenture or the Purchase Agreement in
its ability to do so) immediately prior to the Change in Control Transaction at
the Change in Control Exercise Price (as defined below), and acquired the Change
in Control Consideration as a stockholder of the Company; or



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         (ii) exercise its Warrants into Common Stock at the Change in Control
Exercise Price (as defined below).

                  The "CHANGE IN CONTROL EXERCISE PRICE" shall mean a price,
         subject to adjustments in the same manner as adjustments to the
         Exercise Price, equal to the lesser of: (i) the then existing Exercise
         Price; (ii) 100% of the lowest Market Price for Shares of Common Stock
         for any of the four (4) Trading Days immediately preceding the Public
         Announcement of the Change in Control Transaction; and (iii) 85% of the
         lowest Market Price for Shares of Common Stock on (A) the Trading Day
         on which there was a Public Announcement of the Change in Control
         Transaction and the two (2) Trading Days thereafter or (B) in the event
         that the Public Announcement did not occur on a Trading Day, the three
         (3) Trading Days immediately following the Public Announcement. The
         Market Price for Shares of Common Stock shall be appropriately adjusted
         for stock splits, reverse splits, stock dividends and other dilutive
         events, including those events occurring in connection with the Change
         in Control Transaction, that occur during the Trading Days referred to
         above.

12.      Effect of Certain Events. If at any time while this Warrant or any
         portion thereof is outstanding and unexpired there shall be (i) a sale
         or conveyance of all or substantially all of the Company's assets or
         (ii) a transaction (by merger or otherwise) in which more than 50% of
         the voting power of the Company is disposed of (collectively, a "SALE
         OR MERGER TRANSACTION"), in which the consideration to be received by
         the Company or its stockholders consists solely of cash, and in case
         the Company shall at any time effect a Sale or Merger Transaction in
         which the consideration to be received by the Company or its
         stockholders consists in part of consideration other than cash, the
         holder of this Warrant shall have the right thereafter to purchase, by
         exercise of this Warrant and payment of the aggregate Exercise Price in
         effect immediately prior to such action, the kind and amount of shares
         and other securities and property which it would have owned or have
         been entitled to receive after the happening of such transaction had
         this Warrant been exercised immediately prior thereto, subject to
         further adjustment as provided in Section 13. Notwithstanding the
         above, a Sale or Merger Transaction shall not be deemed to occur in the
         event the Company is the acquiring entity in connection with an
         acquisition by the Company.

13.      Adjustments of Exercise Price and Number of Warrant Shares.

         The number of and kind of securities purchasable upon exercise of this
         Warrant and the Exercise Price shall be subject to adjustment from time
         to time as follows:

(a)      Subdivisions, Combinations and other Issuances. If the Company shall at
         any time after the date hereof but prior to the expiration of this
         Warrant subdivide its outstanding securities as to which purchase
         rights under this Warrant exist, by split-up, spin-off, or otherwise,
         or combine its outstanding securities as to which purchase rights under
         this Warrant exist, the number of Warrant Shares as to which this
         Warrant is exercisable as of the date of such subdivision, split-up,
         spin-off or combination shall forthwith be



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         proportionately increased in the case of a subdivision, or
         proportionately decreased in the case of a combination. Appropriate
         proportional adjustments (decrease in the case of subdivision, increase
         in the case of combination) shall also be made to the Exercise Price
         payable per share, so that the aggregate Exercise Price payable for the
         total number of Warrant Shares purchasable under this Warrant as of
         such date shall remain the same as it would have been before such
         subdivision or combination.

(b)      Stock Dividend. If at any time after the date hereof the Company
         declares a dividend or other distribution on Common Stock payable in
         Common Stock or other securities or rights convertible into Common
         Stock ("COMMON STOCK EQUIVALENTS") without payment of any consideration
         by holders of Common Stock for the additional shares of Common Stock or
         the Common Stock Equivalents (including the additional shares of Common
         Stock issuable upon exercise or conversion thereof), then the number of
         shares of Common Stock for which this Warrant may be exercised shall be
         increased as of the record date (or the date of such dividend
         distribution if no record date is set) for determining which holders of
         Common Stock shall be entitled to receive such dividends, in proportion
         to the increase in the number of outstanding shares (and shares of
         Common Stock issuable upon conversion of all such securities
         convertible into Common Stock) of Common Stock as a result of such
         dividend, and the Exercise Price shall be proportionately reduced so
         that the aggregate Exercise Price for all the Warrant Shares issuable
         hereunder immediately after the record date (or on the date of such
         distribution, if applicable), for such dividend shall equal the
         aggregate Exercise Price so payable immediately before such record date
         (or on the date of such distribution, if applicable).

(c)      Other Distributions. If at any time after the date hereof the Company
         distributes to holders of its Common Stock, other than as part of its
         dissolution, liquidation or the winding up of its affairs, any shares
         of its capital stock, any evidence of indebtedness or any of its assets
         (other than Common Stock), then the number of Warrant Shares for which
         this Warrant is exercisable shall be increased to equal: (i) the number
         of Warrant Shares for which this Warrant is exercisable immediately
         prior to such event, (ii) multiplied by a fraction, (A) the numerator
         of which shall be the Fair Market Value (as defined below) per share of
         Common Stock on the record date for the dividend or distribution, and
         (B) the denominator of which shall be the Fair Market Value price per
         share of Common Stock on the record date for the dividend or
         distribution minus the amount allocable to one share of Common Stock of
         the value (as jointly determined in good faith by the Board of
         Directors of the Company and the Warrant holder) of any and all such
         evidences of indebtedness, shares of capital stock, other securities or
         property, so distributed. For purposes of this Warrant, "FAIR MARKET
         VALUE" shall equal the ten (10) Trading Day average closing trading
         price of the Common Stock on the Principal Market for the ten (10)
         Trading Days preceding the date of determination or, if the Common
         Stock is not listed or admitted to trading on any Principal Market, the
         average of the closing bid and asked prices on the over-the-counter
         market as furnished by any New York Stock Exchange member firm
         reasonably selected from time to time by the Company for that purpose
         and reasonably acceptable to the Holder, or, if the Common Stock is not
         listed or admitted to trading on the Principal Market or traded
         over-the-



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         counter and the average price cannot be determined as contemplated
         above, the Fair Market Value of the Common Stock shall be as reasonably
         determined in good faith by the Company's Board of Directors with the
         concurrence of the Holder. The Exercise Price shall be reduced to
         equal: (i) the Exercise Price in effect immediately before the
         occurrence of any event (ii) multiplied by a fraction, (A) the
         numerator of which is the number of Warrant Shares for which this
         Warrant is exercisable immediately before the adjustment, and (B) the
         denominator of which is the number of Warrant Shares for which this
         Warrant is exercisable immediately after the adjustment.

(d)      Merger, etc. If at any time after the date hereof there shall be a
         merger or consolidation of the Company with or into or a transfer of
         all or substantially all of the assets of the Company to another
         entity, then the Warrant holder shall be entitled to receive upon or
         after such transfer, merger or consolidation becoming effective, and
         upon payment of the Exercise Price then in effect, the number of shares
         or other securities or property of the Company or of the successor
         corporation resulting from such merger or consolidation, which would
         have been received by Warrant holder for the shares of stock subject to
         this Warrant had this Warrant been exercised just prior to such
         transfer, merger or consolidation becoming effective or to the
         applicable record date thereof, as the case may be. The Company will
         not merge or consolidate with or into any other corporation, or sell or
         otherwise transfer its property, assets and business substantially as
         an entirety to another corporation, unless the corporation resulting
         from such merger or consolidation (if not the Company), or such
         transferee corporation, as the case may be, shall expressly assume in
         writing the due and punctual performance and observance of each and
         every covenant and condition of this Warrant to be performed and
         observed by the Company.

(e)      Reclassification, etc. If at any time after the date hereof there shall
         be a reorganization or reclassification of the securities as to which
         purchase rights under this Warrant exist into the same or a different
         number of securities of any other class or classes, then the Warrant
         holder shall thereafter be entitled to receive upon exercise of this
         Warrant, during the period specified herein and upon payment of the
         Exercise Price then in effect, the number of shares or other securities
         or property resulting from such reorganization or reclassification,
         which would have been received by the Warrant holder for the shares of
         stock subject to this Warrant had this Warrant at such time been
         exercised.

(f)      Exercise Price Adjustment. In the event that the Company issues or
         sells any Common Stock or securities which are convertible into or
         exchangeable for its Common Stock or any convertible securities, or any
         warrants or other rights to subscribe for or to purchase or any options
         for the purchase of its Common Stock or any such convertible securities
         (other than shares or options issued or which may be issued pursuant to
         (i) the Company's current or future employee, director or bona fide
         consultant option plans or (ii) arrangements with the Investor) (an
         "INDICATED ISSUANCE"), at an effective issuance or exercise price per
         share which is less than the Fair Market Value, then the Exercise Price
         in effect immediately prior to such issue or sale shall be reduced
         effective concurrently with such issue or sale to an amount determined
         by multiplying the Exercise Price then in effect by a fraction, (x) the
         numerator of which shall be the sum of (1) the number of shares of
         Common Stock



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         outstanding immediately prior to such issue or sale, plus (2) the
         number of shares of Common Stock which the aggregate consideration
         received by the Company for such additional shares would purchase at
         such Exercise Price then in effect; and (y) the denominator of which
         shall be the number of shares of Common Stock of the Company
         outstanding immediately after such issue or sale. In the event the
         Company makes an Indicated Issuance at an effective issuance or
         exercise price which is less than the Exercise Price then in effect,
         then the Exercise Price shall be adjusted downward to equal such lower
         issuance or exercise price concurrently with such Indicated Issuance.

         For the purposes of the foregoing adjustment, in the case of the
         issuance of any convertible securities, warrants, options or other
         rights to subscribe for or to purchase or exchange for, shares of
         Common Stock ("CONVERTIBLE SECURITIES"), the maximum number of shares
         of Common Stock issuable upon exercise, exchange or conversion of such
         Convertible Securities shall be deemed to be outstanding, provided that
         no further adjustment shall be made upon the actual issuance of Common
         Stock upon exercise, exchange or conversion of such Convertible
         Securities.

         The number of shares which may be purchased hereunder shall be
         increased proportionately to any reduction in Exercise Price pursuant
         to this paragraph 13(f), so that after such adjustments the aggregate
         Exercise Price payable hereunder for the increased number of shares
         shall be the same as the aggregate Exercise Price in effect just prior
         to such adjustments.

14.      Voluntary Adjustment by the Company. The Company may at its option, at
         any time during the term of this Warrant, reduce but not increase the
         then current Exercise Price to any amount and for any period of time
         deemed appropriate by the Board of Directors of the Company.

15.      Notice of Adjustment. Whenever the number of Warrant Shares or number
         or kind of securities or other property purchasable upon the exercise
         of this Warrant or the Exercise Price is adjusted, the Company shall
         promptly mail to the holder of this Warrant a notice setting forth the
         number of Warrant Shares (and other securities or property) purchasable
         upon the exercise of this Warrant and the Exercise Price of such
         Warrant Shares after such adjustment and setting forth a brief
         statement of the facts requiring such adjustment.

16.      Authorized Shares. The Company covenants that during the period the
         Warrant is outstanding and exercisable, it will reserve from its
         authorized and unissued Common Stock a sufficient number of shares to
         provide for the issuance of the Warrant Shares upon the exercise of any
         purchase rights under this Warrant. The Company further covenants that
         its issuance of this Warrant shall constitute full authority to its
         officers who are charged with the duty of executing stock certificates
         to execute and issue the necessary certificates for the Warrant Shares
         upon the exercise of the purchase rights under this Warrant. The
         Company will take all such reasonable action as may be necessary to
         assure that such Warrant Shares may be issued as provided herein
         without violation of any applicable law or regulation, or of any
         requirements of the American



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         Stock Exchange or any domestic securities exchange upon which the
         Common Stock may be listed.

17.      9.9% Limitation.

(a)      Notwithstanding anything to the contrary contained herein, the number
         of shares of Common Stock that may be acquired by the Investor upon
         exercise pursuant to the terms hereof shall not exceed a number that,
         when added to the total number of shares of Common Stock deemed
         beneficially owned by such holder (other than by virtue of the
         ownership of securities or rights to acquire securities (including the
         Warrant) that have limitations on the Investor's right to convert,
         exercise or purchase similar to the limitation set forth herein),
         together with all shares of Common Stock deemed beneficially owned
         (other than by virtue of the ownership of securities or rights to
         acquire securities (including the Warrant) that have limitations on the
         right to convert, exercise or purchase similar to the limitation set
         forth herein) by the holder's "affiliates" (as defined Rule 144 of the
         Act) ("AGGREGATION PARTIES") that would be aggregated for purposes of
         determining whether a group under Section 13(d) of the Securities
         Exchange Act of 1934, as amended, exists, would exceed 9.99% of the
         total issued and outstanding shares of the Company's Common Stock (the
         "RESTRICTED OWNERSHIP PERCENTAGE"). Each Holder shall have the right
         (w) at any time and from time to time to reduce its Restricted
         Ownership Percentage immediately upon notice to the Company and (x) at
         any time and from time to time, to increase its Restricted Ownership
         Percentage immediately in the event of the announcement as pending or
         planned of an event of:

         (i)      any consolidation or merger of the Company with or into any
                  other corporation or other entity or person (whether or not
                  the Company is the surviving corporation), or any other
                  corporate reorganization or transaction or series of related
                  transactions in which in excess of 50% of the Company's voting
                  power is transferred through a merger, consolidation, tender
                  offer or similar transaction,

         (ii)     any person (as defined in Section 13(d) of the Exchange Act),
                  together with its affiliates and associates (as such terms are
                  defined in Rule 405 under the 1933 Act), beneficially owns or
                  is deemed to beneficially own (as described in Rule 13d-3
                  under the Exchange Act without regard to the 60-day exercise
                  period) in excess of 50% of the Company's voting power,

         (iii)    there is a replacement of more than one-half of the members of
                  the Company's Board of Directors which is not approved by
                  those individuals who are members of the Company's Board of
                  Directors on the date thereof, in one or a series of related
                  transactions, or

         (iv)     a sale or transfer of all or substantially all of the assets
                  of the Company, determined on a consolidated basis.

(b)      The Investor covenants at all times on each day (each such day being
         referred to as a "COVENANT DAY") as follows: During the balance of such
         Covenant Day and the



                                       10
<PAGE>   11


         succeeding sixty-one (61) days (the balance of such Covenant Day and
         the succeeding sixty-one (61) days being referred to as the "COVENANT
         PERIOD") such Investor will not acquire shares of Common Stock pursuant
         to any right (including the exercise of the Warrant) existing at the
         commencement of the Covenant Period to the extent the number of shares
         so acquired by such holder and its Aggregation Parties (ignoring all
         dispositions) would exceed:

         (x)      the Restricted Ownership Percentage of the total number of
                  shares of Common Stock outstanding at the commencement of the
                  Covenant Period,

         minus

         (y)      the number of shares of Common Stock owned by such holder and
                  its Aggregation Parties at the commencement of the Covenant
                  Period.

                  A new and independent covenant will be deemed to be given by
         the holder as of each moment of each Covenant Day. No covenant will
         terminate, diminish or modify any other covenant. The holder agrees to
         comply with each such covenant. This Section 17 controls in the case of
         any conflict with any other provision of the Transaction Documents.

                  The Company's obligation to issue shares of Common Stock which
         would exceed such limits referred to in this Section 17 shall be
         suspended to the extent necessary until such time, if any, as shares of
         Common Stock may be issued in compliance with such restrictions.

18.      Compliance with Securities Laws.

(a)      The holder hereof acknowledges that the Warrant Shares acquired upon
         the exercise of this Warrant, if not registered (or if no exemption
         from registration exists), will have restrictions upon resale imposed
         by state and federal securities laws. Each certificate representing the
         Warrant Shares issued to the Holder upon exercise (if not registered or
         if no exemption from registration exists) will bear the following
         legend:

         THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
         WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES
         COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION
         UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"),
         AND, ACCORDINGLY, MAY NOT BE OFFERED, TRANSFERRED, SOLD OR OTHERWISE
         DISPOSED OF EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT
         UNDER THE SECURITIES ACT OR PURSUANT TO AN AVAILABLE EXEMPTION FROM, OR
         IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION REQUIREMENTS OF THE
         SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE SECURITIES LAWS,
         BASED ON AN OPINION LETTER OF COUNSEL



                                       11
<PAGE>   12


         SATISFACTORY TO THE COMPANY OR A NO-ACTION LETTER FROM THE SECURITIES
         AND EXCHANGE COMMISSION.

(b)      Without limiting the Investor's right to transfer, assign or otherwise
         convey the Warrant or Warrant Shares in compliance with all applicable
         securities laws, the Investor of this Warrant, by acceptance hereof,
         acknowledges that this Warrant and the Warrant Shares to be issued upon
         exercise hereof are being acquired solely for the Investor's own
         account and not as a nominee for any other party, and that the Investor
         will not offer, sell or otherwise dispose of this Warrant or any
         Warrant Shares to be issued upon exercise hereof except under
         circumstances that will not result in a violation of applicable federal
         and state securities laws. Upon exercise of this Warrant, the Investor
         shall, if requested by the Company, confirm in writing, in a form
         satisfactory to the Company, that the Warrant Shares of Common Stock so
         purchased are being acquired solely for the Investor's own account and
         not as a nominee for any other party, for investment, and not with a
         view toward distribution or resale.

(c)      Neither this Warrant nor any share of Common Stock issued upon exercise
         of this Warrant may be offered for sale or sold, or otherwise
         transferred or sold in any transaction which would constitute a sale
         thereof within the meaning of the Act, unless (i) such security has
         been registered for sale under the Act and registered or qualified
         under applicable state securities laws relating to the offer an sale of
         securities, or (ii) exemptions from the registration requirements of
         the Act and the registration or qualification requirements of all such
         state securities laws are available and the Company shall have received
         an opinion of counsel that the proposed sale or other disposition of
         such securities may be effected without registration under the Act,
         such counsel and such opinion to be satisfactory to the Company.

(d)      Investor recognizes that investing in the Warrant and the Warrant
         Shares involves a high degree of risk, and Investor is in a financial
         position to hold the Warrant and the Warrant Shares indefinitely and is
         able to bear the economic risk and withstand a complete loss of its
         investment in the Warrant and the Warrant Shares. The Investor is a
         sophisticated investor and is capable of evaluating the merits and
         risks of investing in the Company. The Investor has had an opportunity
         to discuss the Company's business, management and financial affairs
         with the Company's management, has been given full and complete access
         to information concerning the Company, and has utilized such access to
         its satisfaction for the purpose of obtaining information or verifying
         information and has had the opportunity to inspect the Company's
         operation. Investor has had the opportunity to ask questions of, and
         receive answers from, the management of the Company (and any person
         acting on its behalf) concerning the Warrant and the Warrant Shares and
         the agreements and transactions contemplated hereby, and to obtain any
         additional information as Investor may have requested in making its
         investment decision. The initial Investor in this Warrant is an
         "accredited investor", as defined by Regulation D promulgated under the
         Act.



                                       12
<PAGE>   13


19.      Miscellaneous.

(a)      Issue Date; Choice Of Law; Venue; Jurisdiction. The provisions of this
         Warrant shall be construed and shall be given effect in all respects as
         if it had been issued and delivered by the Company on the date hereof.
         This Warrant shall be binding upon any successors or assigns of the
         Company. This Warrant will be construed and enforced in accordance with
         and governed by the laws of the State of New York, except for matters
         arising under the Act, without reference to principles of conflicts of
         law. Each of the parties consents to the exclusive jurisdiction of the
         U.S. District Court sitting in the State of City of New York in the
         State of New York in connection with any dispute arising under this
         Warrant and hereby waives, to the maximum extent permitted by law, any
         objection, including any objection based on forum non conveniens, to
         the bringing of any such proceeding in such jurisdiction. Each party
         hereby agrees that if the other party to this Warrant obtains a
         judgment against it in such a proceeding, the party which obtained such
         judgment may enforce same by summary judgment in the courts of any
         country having jurisdiction over the party against whom such judgment
         was obtained, and each party hereby waives any defenses available to it
         under local law and agrees to the enforcement of such a judgment. Each
         party to this Warrant irrevocably consents to the service of process in
         any such proceeding by the mailing of copies thereof by registered or
         certified mail, postage prepaid, to such party at its address in
         accordance with Section 18(c). Nothing herein shall affect the right of
         any party to serve process in any other manner permitted by law. Each
         party waives its right to a trial by jury.

(b)      Modification and Waiver. This Warrant and any provisions hereof may be
         changed, waived, discharged or terminated only by an instrument in
         writing signed by the party against which enforcement of the same is
         sought. Any amendment effected in accordance with this paragraph shall
         be binding upon the Investor, each future holder of this Warrant and
         the Company. No waivers of, or exceptions to, any term, condition or
         provision of this Warrant, in any one or more instances, shall be
         deemed to be, or construed as, a further or continuing waiver of any
         such term, condition or provision.

(c)      Notices. Any notice, request or other document required or permitted to
         be given or delivered to the Investor or future holders hereof or the
         Company shall be personally delivered or shall be sent by certified or
         registered mail, postage prepaid, to the Investor or each such holder
         at its address as shown on the books of the Company or to the



                                       13
<PAGE>   14

         Company at the address set forth in the Agreement. All notices under
         this Warrant shall be deemed to have been given when received.

         A party may from time to time change the address to which notices to it
         are to be delivered or mailed hereunder by notice in accordance with
         the provisions of this Section 19(c).

(d)      Severability. Whenever possible, each provision of this Warrant shall
         be interpreted in such manner as to be effective and valid under
         applicable law, but if any provision of this Warrant is held to be
         invalid, illegal or unenforceable in any respect under any applicable
         law or rule in any jurisdiction, such invalidity, illegality or
         unenforceability shall not affect the validity, legality or
         enforceability of any other provision of this Warrant in such
         jurisdiction or affect the validity, legality or enforceability of any
         provision in any other jurisdiction, but this Warrant shall be
         reformed, construed and enforced in such jurisdiction as if such
         invalid, illegal or unenforceable provision had never been contained
         herein.

(e)      No Impairment. The Company will not, by amendment of its Certificate of
         Incorporation or through any reorganization, transfer of assets,
         consolidation, merger, dissolution, issue or sale of securities or any
         other voluntary action, avoid or seek to avoid the observance or
         performance of any of the terms of this Warrant, but will at all times
         in good faith assist in the carrying out of all such terms and in the
         taking of all such action as may be necessary or appropriate in order
         to protect the rights of the Warrant holder against impairment. Without
         limiting the generality of the foregoing, the Company (a) will not
         increase the par value of any Warrant Shares above the amount payable
         therefor on such exercise, and (b) will take all such action as may be
         reasonably necessary or appropriate in order that the Company may
         validly and legally issue fully paid and nonassessable Warrant Shares
         on the exercise of this Warrant.



                                       14
<PAGE>   15


         IN WITNESS WHEREOF, the Company has caused this Warrant to be executed
by its officers thereunto duly authorized.

Dated:  October 13, 2000

                                         ZYMETX, INC.



                                         By:
                                            --------------------------
                                            Norman R. Proulx
                                            Chief Executive Officer






                                       15
<PAGE>   16


                               NOTICE OF EXERCISE



To:      ZYMETX, INC.

(1)      The undersigned hereby elects:

         (A) to purchase ________ shares of Common Stock of ZymeTx, Inc.
pursuant to the terms of the attached Warrant, and tenders herewith payment of
the Exercise Price in full, together with all applicable transfer taxes, if any.

         (B) in a "cashless" or "net-issue exercise" for, and to purchase
thereunder, ______ shares of Common Stock, and herewith makes payment therefor
with _______ Exercised Shares.

(2) Please issue a certificate or certificates representing said shares of
Common Stock in the name of the undersigned or in such other name as is
specified below:

                           -------------------------------
                           (Name)

                           -------------------------------
                           (Address)

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

(3) Please issue a new Warrant for the unexercised portion of the attached
Warrant in the name of the undersigned or in such other name as is specified
below:

                           Other Name:
                                      ---------------------



                                     -----------------------------------
                                     (Name)

--------------------                 -----------------------------------
(Date)                               (Signature)

                                     -----------------------------------
                                     (Address)




                                       16
<PAGE>   17


                                 ASSIGNMENT FORM

                    (To assign the foregoing warrant, execute
                   this form and supply required information.
                 Do not use this form to exercise the warrant.)



         FOR VALUE RECEIVED, the foregoing Warrant of ZymeTx, Inc. and all
rights evidenced thereby are hereby assigned to

                                             whose address is
--------------------------------------------

---------------------------------------------------------------.



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

                                          Dated:                   ,
                                                 ------------------

                           Holder's Signature:
                                               ---------------------------

                           Holder's Address:
                                               ---------------------------

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



Signature Guaranteed:
                     -------------------------------------------------




NOTE: The signature to this Assignment Form must correspond with the name as it
appears on the face of the Warrant, without alteration or enlargement or any
change whatsoever, and must be guaranteed by a bank or trust company. Officers
of corporations and those acting in an fiduciary or other representative
capacity should file proper evidence of authority to assign the foregoing
Warrant.