Document:

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                                                                EXHIBIT 4.3

THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933, AND HAVE BEEN ACQUIRED FOR INVESTMENT AND NOT
WITH A VIEW TO, OR IN CONNECTION WITH, THE SALE OR DISTRIBUTION THEREOF. NO
SUCH SALE OR DISPOSITION MAY BE EFFECTED WITHOUT AN EFFECTIVE REGISTRATION
STATEMENT RELATED THERETO OR AN OPINION OF COUNSEL FOR THE COMPANY THAT SUCH
REGISTRATION IS NOT REQUIRED UNDER THE SECURITIES ACT OF 1933.
-------------------------------------------------------------------------------

Warrant No. WA-1                                       Number of Shares: 58,500
Date of Issuance: December 9, 1997                     (subject to adjustment)

                                  VERSICOR INC.

                    SERIES C PREFERRED STOCK PURCHASE WARRANT

         Versicor Inc. (the "COMPANY"), for value received, hereby certifies
that Healthcare Ventures V or its registered assigns (the "REGISTERED
HOLDER"), is entitled, subject to the terms set forth below, to purchase from
the Company, at any time after the date hereof and on or before December 9,
2002, up to 58,500 shares of Series C Preferred Stock of the Company
("PREFERRED STOCK"), at a purchase price of $5.00 per share. The number of
shares purchasable upon exercise of this Warrant, and the purchase price per
share, each as adjusted from time to time pursuant to the provisions of this
Warrant, are hereinafter referred to as the "WARRANT STOCK" and the "PURCHASE
PRICE," respectively.

         1.       EXERCISE.

                  (a)   This Warrant may be exercised by the Registered
Holder, in whole or in part, by surrendering this Warrant, with the purchase
form appended hereto as EXHIBIT A duly executed by such Registered Holder or
by such Registered Holder's duly authorized attorney, at the principal office
of the Company, or at such other office or agency as the Company may
designate, accompanied by payment in full by cash, check or wire transfer of
the Purchase Price payable in respect of the number of shares of Warrant
Stock purchased upon such exercise.

                  (b)   Each exercise of this Warrant shall be deemed to have
been effected immediately prior to the close of business on the day on which
this Warrant shall have been surrendered to the Company as provided in
Section 1(a) above. At such time, the person or persons in whose name or
names any certificates for Warrant Stock shall be issuable upon such exercise
as provided in Section 1(d) below shall be deemed to have become the holder
or holders of record of the Warrant Stock represented by such certificates.

                  (c)   NET ISSUE EXERCISE.

                        (i)  In lieu of exercising this Warrant in the manner
provided above in Section 1(a), the Registered Holder may elect to receive
shares equal to the value of this Warrant (or the portion thereof being
canceled) by surrender of this Warrant at the principal office of the

<PAGE>

(or the portion thereof being canceled) by surrender of this Warrant at the
principal office of the Company together with notice of such election in
which event the Company shall issue to holder a number of shares of Preferred
Stock computed using the following formula:

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

Where             X = The number of shares of Preferred Stock to be issued to
                        the Registered Holder.

                  Y = The number of shares of Preferred Stock purchasable
                        under this Warrant (at the date of such calculation).

                  A = The fair market value of one share of Preferred Stock
                        (at the date of such calculation).

                  B = The Purchase Price (as adjusted to the date of such
                        calculation).

                           (ii)   For purposes of this Section 1(c), the fair
market value of Preferred Stock shall be the price per share which the
Company could obtain from a willing buyer for the shares sold by the Company
from authorized but unissued shares, as such price shall be agreed by the
Company and the Registered Holder.

                  (d)   As soon as practicable after the exercise of this
Warrant in full or in part, and in any event within 10 days thereafter, the
Company at its expense will cause to be issued in the name of, and delivered
to, the Registered Holder, or as such Holder (upon payment by such Holder of
any applicable transfer taxes) may direct:

                           (i)    a certificate or certificates for the
number of shares of Warrant Stock to which such Registered Holder shall be
entitled, and

                           (ii)   in case such exercise is in part only, a
new warrant or warrants (dated the date hereof) of like tenor, calling in the
aggregate on the face or faces thereof for the number of shares of Warrant
Stock equal (without giving effect to any adjustment therein) to the number
of such shares called for on the face of this Warrant minus the number of
such shares purchased by the Registered Holder upon such exercise as provided
in Section 1(a) above.

         2.       ADJUSTMENTS

                  (a)   If outstanding shares of the Company's Preferred
Stock shall be subdivided into a greater number of shares or a dividend in
Preferred Stock shall be paid in respect of Preferred Stock, the Purchase
Price in effect immediately prior to such subdivision or at the record date
of such dividend shall simultaneously with the effectiveness of such
subdivision or immediately after the record date of such dividend be
proportionately reduced. If outstanding shares of Preferred Stock shall be
combined into a smaller number of shares, the Purchase Price in effect
immediately prior to such combination shall, simultaneously with the

<PAGE>

required to be made in the Purchase Price, the number of shares of Warrant
Stock purchasable upon the exercise of this Warrant shall be changed to the
number determined by dividing (i) an amount equal to the number of shares
issuable upon the exercise of this Warrant immediately prior to such
adjustment, multiplied by the Purchase Price in effect immediately prior to
such adjustment, by (ii) the Purchase Price in effect immediately after such
adjustment.

                  (b)   In case of any reclassification or change of the
outstanding securities of the Company or of any reorganization of the Company
(or any other corporation the stock or securities of which are at the time
receivable upon the exercise of this Warrant) or any similar corporate
reorganization on or after the date hereof, then and in each such case the
holder of this Warrant, upon the exercise hereof at any time after the
consummation of such reclassification, change, reorganization, merger or
conveyance, shall be entitled to receive, in lieu of the stock or other
securities and property receivable upon the exercise hereof prior to such
consummation, the stock or other securities or property to which such holder
would have been entitled upon such consummation if such holder had exercised
this Warrant immediately prior thereto, all subject to further adjustment as
provided in paragraph (a); and in each such case, the terms of this Section 2
shall be applicable to the shares of stock or other securities properly
receivable upon the exercise of this Warrant after such consummation.

                  (c)   When any adjustment is required to be made in the
Purchase Price, the Company shall promptly mail to the Registered Holder a
certificate setting forth the Purchase Price after such adjustment and
setting forth a brief statement of the facts requiring such adjustment. Such
certificate shall also set forth the kind and amount of stock or other
securities or property into which this Warrant shall be exercisable following
the occurrence of any of the events specified in Section 2(a) or (b) above.

                  (d)   In order to avoid doubt, it is acknowledged that the
holder of this Warrant shall be entitled to the benefit of all adjustments in
the number of shares of Common Stock of the Company issuable upon conversion
of the Preferred Stock of the Company which occur prior to the exercise of
this Warrant, including without limitation, any increase in the number of
shares of Common Stock issuable upon conversion as a result of a dilutive
issuance of capital stock.

         3.       TRANSFERS.

                  (a)   Each holder of this Warrant acknowledges that this
Warrant, the Warrant Stock and the Common Stock of the Company have not been
registered under the Securities Act of 1933, as amended (the "Securities
Act"), and agrees not to sell, pledge, distribute, offer for sale, transfer
or otherwise dispose of this Warrant, any Warrant Stock issued upon its
exercise or any Common Stock issued upon conversion of the Warrant Stock in
the absence of (i) an effective registration statement under the Act as to
this Warrant, such Warrant Stock or such Common Stock and registration or
qualification of this Warrant, such Warrant Stock or such Common Stock under
any applicable Blue Sky or state securities law then in effect, or (ii) an
opinion of counsel, satisfactory to the Company, that such registration and
qualification are not required. Each certificate or other instrument for
Warrant Stock issued upon the exercise of this Warrant shall bear a legend
substantially to the foregoing effect.

<PAGE>

                  (b)   Subject to the provisions of Section 3(a) hereof,
this Warrant and all rights hereunder are transferable, in whole or in part,
upon surrender of the Warrant with a properly executed assignment (in the
form of EXHIBIT B hereto) at the principal office of the Company.

                  (c)   Until any transfer of this Warrant is made in the
warrant register, the Company may treat the Registered Holder of this Warrant
as the absolute owner hereof for all purposes; PROVIDED, HOWEVER, that if and
when this warrant is properly assigned in blank, the Company may (but shall
not be required to) treat the bearer hereof as the absolute owner hereof for
all purposes, notwithstanding any notice to the contrary.

                  (d)   The Company will maintain a register containing the
names and addresses of the Registered Holders of this Warrant. Any Registered
Holder may change such Registered Holder's address as shown on the warrant
register by written notice to the Company requesting such change.

         4.       NO IMPAIRMENT. The Company will not, by amendment of its
charter or through reorganization, consolidation, merger, dissolution, sale
of assets 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 holder of this Warrant against impairment.

         5.       LIQUIDATING DIVIDENDS. If the Company pays a dividend or
makes a distribution on the Preferred Stock payable otherwise than in cash
out of earnings or earned surplus (determined in accordance with generally
accepted accounting principles) except for a stock dividend payable in shares
of Preferred Stock (a "LIQUIDATING DIVIDEND"), then the Company will pay or
distribute to the Registered Holder of this Warrant, upon the exercise
hereof, in addition to the Warrant Stock purchased upon such exercise, the
Liquidating Dividend which would have been paid to such Registered Holder if
he had been the owner of record of such shares of Warrant Stock immediately
prior to the date on which a record was taken for such Liquidating Dividend
or, if no record was taken, the date as of which the record holders of
Preferred Stock entitled to such dividends or distribution were determined.

         6.       TERMINATION. This Warrant (and the right to purchase
securities upon exercise hereof) shall terminate on December 9, 2002.

         7.       NOTICES OF CERTAIN TRANSACTIONS. In case:

                  (a)   the Company shall take a record of the holders of its
Preferred Stock (or other stock or securities at the time deliverable upon
the exercise of this Warrant) for the purpose of entitling or enabling them
to receive any dividend or other distribution, or to receive any right to
subscribe for or purchase any shares of stock of any class or any other
securities, or to receive any other right, to subscribe for or purchase any
shares of stock of any class or any other securities, or to receive any other
right, or

                  (b)   of any capital reorganization of the Company, any
reclassification of the capital stock of the Company, any consolidation or
merger of the Company, any consolidation or

<PAGE>

                  (b)   of any capital reorganization of the Company, any
reclassification of the capital stock of the Company, any consolidation or
merger of the Company any consolidation or merger of the Company with or
into another corporation (other than a consolidation or merger in which the
Company is the surviving entity), or any transfer of all or substantially all
of the assets of the Company, or

                  (c)   of the voluntary or involuntary dissolution,
liquidation or winding-up of the Company, or

                  (d)   of any redemption of the Preferred Stock or mandatory
conversion of the Preferred Stock into Common Stock of the Company,

then, and in each such case, the Company will mail or cause to be mailed to
the Registered Holder of this Warrant a notice specifying, as the case may
be, (i) the date on which a record is to be taken for the purpose of such
dividend, distribution or right, and stating the amount and character of such
dividend, distribution or right, or (ii) the effective date on which such
reorganization, reclassification, consolidation, merger, transfer,
dissolution, liquidation, winding-up, redemption or conversion is to take
place, and the time, if any is to be fixed, as of which the holders of record
of Preferred Stock (or such other stock or securities at the time deliverable
upon such reorganization, reclassification, consolidation, merger, transfer,
dissolution, liquidation, winding-up, redemption or conversion) are to be
determined. Such notice shall be mailed at least ten (10) days prior to the
record date or effective date for the event specified in such notice.

         8.       RESERVATION OF STOCK. The Company will at all times reserve
and keep available, solely for the issuance and delivery upon the exercise of
this Warrant, such shares of Warrant Stock and other stock, securities and
property, as from time to time shall be issuable upon the exercise of this
Warrant.

         9.       EXCHANGE OF WARRANTS. Upon the surrender by the Registered
Holder of any Warrant or Warrants, properly endorsed, to the Company at the
principal office of the Company, the Company will, subject to the provisions
of Section 3 hereof, issue and deliver to or upon the order of such Holder,
at the Company's expense, a new Warrant or Warrants of like tenor, in the
name of such Registered Holder or as such Registered Holder (upon payment by
such Registered Holder of any applicable transfer taxes) may direct, calling
in the aggregate on the face or faces thereof for the number of shares of
Preferred Stock called for on the face or faces of the Warrant or Warrants so
surrendered.

         10.      REPLACEMENT OF WARRANTS. Upon receipt of evidence
reasonably satisfactory to the Company of the loss, theft, destruction or
mutilation of this Warrant and (in the case of loss, theft or destruction)
upon delivery of an indemnity agreement (with surety if reasonably required)
in an amount reasonably satisfactory to the Company, or (in the case of
mutilation) upon surrender and cancellation of this Warrant, the Company will
issue, in lieu thereof, a new Warrant of like tenor.

         11.      MAILING OF NOTICES. Any notice required or permitted
pursuant to this Warrant shall be in writing and shall be deemed sufficient
when delivered personally or sent by telegram

<PAGE>

or fax or forty-eight (48) hours after being deposited in the U.S. mail, as
certified or registered mail, with postage prepaid, addressed (a)if to the
Registered Holder, to the address of the Registered Holder most recently
furnished in writing to the Company and (b) if to the Company, to the address
set forth below or subsequently modified by written notice to the Registered
Holder.

         12.      NO RIGHTS AS STOCKHOLDER. Until the exercise of this
Warrant, the Registered Holder of this Warrant shall not have or exercise any
rights by virtue hereof as a stockholder of the Company.

         13.      NO FRACTIONAL SHARES. No fractional shares of Preferred
Stock will be issued in connection with any exercise hereunder. In lieu of
any fractional shares which would otherwise be issuable, the Company shall
pay cash equal to the product of such fraction multiplied by the fair market
value of one share of Preferred Stock on the date of exercise, as determined
in good faith by the Company's Board of Directors.

         14.      AMENDMENT OR WAIVER. Any term of this Warrant may be
amended or waived only by an instrument in writing signed by the party
against which enforcement of the amendment or waiver is sought.

         15.      HEADINGS. The headings in this Warrant are for purposes of
reference only and shall not limit or otherwise affect the meaning of any
provision of this Warrant.

         16.      GOVERNING LAW. This Warrant shall be governed, construed
and interpreted in accordance with the laws of the State of Delaware, without
giving effect to principles of conflicts of law.

                                       VERSICOR INC.

                                       By    /s/ G. F. HORNER III
                                         -------------------------------------

                                       Address:
                                               -------------------------------

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

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

<PAGE>

                                    EXHIBIT A

                                  PURCHASE FORM

To:      VERSICOR INC.                                              Dated:

         The undersigned, pursuant to the provisions set forth in the
attached Warrant, hereby irrevocably elects to purchase _____ shares of the
Preferred Stock covered by such Warrant and herewith makes payment of $_____,
representing the full purchase price for such shares at the price per share
provided for in such Warrant.

                                        Signature:
                                                  ----------------------------

                                        Address:
                                                ------------------------------

<PAGE>

                                    EXHIBIT B

                                 ASSIGNMENT FORM

         FOR VALUE RECEIVED, __________________________________ hereby sells,
assigns and transfers all of the rights of the undersigned under the attached
Warrant with respect to the number of shares of Series C Preferred Stock
covered thereby set forth below, unto:

   NAME OF ASSIGNEE                 ADDRESS                    NO. OF SHARES

Dated:                                           Signature:
      ---------------------------                          -------------------

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

                                                 Witness:
                                                         ---------------------<PAGE>

                                                                    Exhibit 4.4

                                                                       NO. PW-1

THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE BEEN ACQUIRED FOR INVESTMENT
AND HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED OR ANY
STATE SECURITIES LAWS. SUCH SECURITIES MAY NOT BE SOLD OR TRANSFERRED IN THE
ABSENCE OF SUCH REGISTRATION OR AN EXEMPTION THEREFROM UNDER SAID ACT AND ANY
APPLICABLE STATE SECURITIES LAWS.

                           WARRANT TO PURCHASE SHARES
                              OF PREFERRED STOCK OF
                                  VERSICOR INC.

         This certifies that HEALTHCARE VENTURES V or its assigns (the
"HOLDER"), for value received, is entitled to purchase from VERSICOR INC., a
Delaware corporation (the "COMPANY"), having a place of business at 34790
Ardentech Court, Fremont, California, the number and type of fully paid and
nonassessable shares of the Company's Preferred Stock, and at a per share
exercise price, to be determined as follows:

         (i) This Warrant shall entitle the Holder to purchase the number of
shares of the Company's applicable Preferred Stock (as determined in (ii) below)
equal to $343,345 divided by the applicable per share exercise price (the "STOCK
PURCHASE PRICE") of the relevant Preferred Stock (as determined in (ii) below).

         (ii) The type of Preferred Stock issuable upon exercise of this Warrant
and the Stock Purchase Price of this Warrant shall be determined as follows:

                  (A) If the Company sells and issues shares of its Series F
         Preferred Stock (the "SERIES F STOCK") to investors with total gross
         proceeds to the Company of not less than $15,000,000 (excluding the
         conversion of the Notes, as such term is defined in the Note and
         Warrant Purchase Agreement of even date herewith among the Company and,
         INTER ALIA, the Holder) (the "EQUITY FINANCING") on or prior to the
         exercise of the Warrant, then the Warrant shall be exerciseable for
         shares of Series F Stock at a Stock Purchase Price equal to the price
         per share paid by the investors purchasing the Series F Stock in the
         Equity Financing.

                  (B) If the Company does not complete an Equity Financing on or
         prior to the exercise of the Warrant, then the Warrant shall be
         exerciseable for shares of Series C Preferred Stock at a Stock Purchase
         Price equal to $5.00.

<PAGE>

         Holder may purchase such shares of Preferred Stock for cash at any time
or from time to time after the Company has authorized and reserved adequate
shares of capital stock for issuance upon conversion of this Warrant and up to
and including 5:00 p.m. (Pacific time) on the earlier of (i) five (5) years from
the closing of the initial public offering of the Company's Common Stock
pursuant to a registration statement under the Securities Act of 1933, as
amended (the "INITIAL PUBLIC OFFERING") or (ii) ten (10) years from the date of
this Warrant, such earlier day being referred to herein as the "EXPIRATION
DATE", upon surrender to the Company at its principal office (or at such other
location as the Company may advise the Holder in writing) of this Warrant
properly endorsed with the Form of Subscription attached hereto duly filled in
and signed and, if applicable, upon payment in cash or by check of the aggregate
Stock Purchase Price for the number of shares for which this Warrant is being
exercised determined in accordance with the provisions hereof; provided,
however, that the Company shall have authorized and reserved adequate shares of
capital stock for which this Warrant is exerciseable. The Stock Purchase Price
and the number of shares purchasable hereunder are subject to adjustment as
provided in Section 3 of this Warrant.

         This Warrant is subject to the following terms and conditions:

         1.       EXERCISE; ISSUANCE OF CERTIFICATES; PAYMENT FOR SHARES.

                  1.1 GENERAL. This Warrant is exercisable at the option of the
holder of record hereof, at any time or from time to time after the Company has
authorized and reserved adequate shares of capital stock for issuance upon
conversion of this Warrant and up to the Expiration Date for all or any part of
the shares of Preferred Stock (but not for a fraction of a share) which may be
purchased hereunder. The Company agrees that the shares of Preferred Stock
purchased under this Warrant shall be and are deemed to be issued to the Holder
hereof as the record owner of such shares as of the close of business on the
date on which this Warrant shall have been surrendered, properly endorsed, the
completed, executed Form of Subscription delivered and payment made for such
shares. Certificates for the shares of Preferred Stock so purchased, together
with any other securities or property to which the Holder hereof is entitled
upon such exercise, shall be delivered to the Holder hereof by the Company at
the Company's expense within a reasonable time after the rights represented by
this Warrant have been so exercised. In case of a purchase of less than all the
shares which may be purchased under this Warrant, the Company shall cancel this
Warrant and execute and deliver a new Warrant or Warrants of like tenor for the
balance of the shares purchasable under the Warrant surrendered upon such
purchase to the Holder hereof within a reasonable time. Each stock certificate
so delivered shall be in such denominations of Preferred Stock as may be
requested by the Holder hereof and shall be registered in the name of such
Holder.

                  1.2 NET ISSUE EXERCISE. Notwithstanding any provisions herein
to the contrary, if the fair market value of one share of the Company's
Preferred Stock issuable upon exercise of this Warrant is greater than the Stock
Purchase Price (at the date of calculation as set forth below), in lieu of
exercising this Warrant for cash, the Holder may elect to receive shares equal
to the value (as determined below) of this Warrant (or the portion thereof being
canceled) by surrender of this Warrant at the principal office of the Company
together with the properly

                                       2.
<PAGE>

endorsed Form of Subscription and notice of such election in which event the
Company shall issue to the Holder a number of shares of Preferred Stock computed
using the following formula:

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

     Where X = the number of shares of Preferred Stock to be issued to the
     Holder

                    Y = the number of shares of Preferred Stock purchasable
                    under the Warrant or, if only a portion of the Warrant is
                    being exercised, the portion of the Warrant being canceled
                    (at the date of such calculation)

                    A = the fair market value of one share of the Company's
                    Preferred Stock (at the date of such calculation)

                    B = Stock Purchase Price (as adjusted to the date of such
                    calculation)

For purposes of the above calculation, fair market value of one share of
Preferred Stock shall be determined as follows:

         (i) If this Warrant is exercised in connection with the Initial Public
Offering, then the fair market value shall be (A) the initial "Price to Public"
specified in the final prospectus with respect to such offering multiplied by
(B) the number of shares of Common Stock into which each share of Preferred
Stock is convertible in connection with the Initial Public Offering.

         (ii) If this Warrant is exercised when the Common Stock is traded on a
securities exchange or the Nasdaq market, then the fair market value per share
shall equal (A) the average of the closing or last reported sale prices on such
exchange or market over the 30-day period ending fifteen (15) business days
prior to the date of exercise of this Warrant multiplied by (B) the number of
shares of Common Stock into which each share of Preferred Stock is convertible
at the time of such exercise,.

         (iii) Otherwise, the fair market value shall be determined in good
faith by the Board of Directors of the Company.

         2.   SHARES TO BE FULLY PAID; RESERVATION OF SHARES. The Company
agrees to ensure, as soon as reasonably practicable after the date of this
Warrant and as requested by the Purchasers (as such term is defined in the
Note and Warrant Purchase Agreement of even date herewith, among the Company
and, INTER ALIA, the Holder), that all shares of Preferred Stock which may be
issued upon the exercise of the rights represented by this Warrant will, upon
issuance, be duly authorized, validly issued, fully paid and nonassessable
and free from all preemptive rights of any stockholder and free of all taxes,
liens and charges with respect to the issue thereof. The Company further
agrees, as soon as reasonably practicable after the date of this Warrant and
as requested by the Purchasers (as such term is defined in the Note and
Warrant

                                       3.
<PAGE>

Purchase Agreement of even date herewith, among the Company and, INTER ALIA, the
Holder), to have authorized and reserved, for the purpose of issue or transfer
upon exercise of the subscription rights evidenced by this Warrant, a sufficient
number of shares of authorized but unissued Preferred Stock, or other securities
and property, when and as required to provide for the exercise of the rights
represented by this Warrant. The Company will take all such action as may be
necessary to assure that such shares of Preferred Stock may be issued as
provided herein without violation of any applicable law or regulation, or of any
requirements of any domestic securities exchange upon which the Preferred Stock
may be listed; provided, however, that the Company shall not be required to
effect a registration under Federal or State securities laws with respect to
such exercise.

         3.   ADJUSTMENT OF STOCK PURCHASE PRICE AND NUMBER OF SHARES. The
Stock Purchase Price and the number of shares purchasable upon the exercise
of this Warrant shall be subject to adjustment from time to time upon the
occurrence of certain events described in this Section 3. Upon each
adjustment of the Stock Purchase Price, the Holder of this Warrant shall
thereafter be entitled to purchase, at the Stock Purchase Price resulting
from such adjustment, the number of shares obtained by multiplying the Stock
Purchase Price in effect immediately prior to such adjustment by the number
of shares purchasable pursuant hereto immediately prior to such adjustment,
and dividing the product thereof by the Stock Purchase Price resulting from
such adjustment. In addition, in the event the outstanding Preferred Stock of
the Company converts into Common Stock in connection with the Initial Public
Offering (the "PREFERRED STOCK CONVERSION") and this Warrant remains
outstanding after such Initial Public Offering, then this Warrant shall be
exerciseable for the number of shares of the Company's Common Stock issuable
upon conversion of the Preferred Stock underlying this Warrant immediately
prior to the Preferred Stock Conversion, and the number of such shares of
Common Stock and the Stock Purchase Price shall be subject to adjustment in
the same manner as provided forth herein.

                  3.1 SUBDIVISION OR COMBINATION OF STOCK. In case the Company
shall at any time subdivide its outstanding shares of Preferred Stock which may
be issued upon the exercise of the rights represented by this Warrant into a
greater number of shares, the Stock Purchase Price in effect immediately prior
to such subdivision shall be proportionately reduced, and conversely, in case
the outstanding shares of Preferred Stock of the Company which may be issued
upon the exercise of the rights represented by this Warrant shall be combined
into a smaller number of shares, the Stock Purchase Price in effect immediately
prior to such combination shall be proportionately increased.

                  3.2 DIVIDENDS IN PREFERRED STOCK, OTHER STOCK, PROPERTY,
RECLASSIFICATION. If at any time or from time to time the Holders of Preferred
Stock which may be issued upon the exercise of the rights represented by this
Warrant (or any shares of stock or other securities at the time receivable upon
the exercise of this Warrant) shall have received or become entitled to receive,
without payment therefor,

                           (a) Preferred Stock or any shares of stock or
other securities which are at any time directly or indirectly convertible
into or exchangeable for Preferred Stock, or any

                                       4.
<PAGE>

rights or options to subscribe for, purchase or otherwise acquire any of the
foregoing by way of dividend or other distribution.

                           (b) any cash paid or payable otherwise than as a cash
dividend, or

                           (c) Preferred Stock or additional stock or other
securities or property (including cash) by way of spinoff, split-up,
reclassification, combination of shares or similar corporate rearrangement,
(other than shares of Preferred Stock issued as a stock split or adjustments in
respect of which shall be covered by the terms of Section 3.1 above), then and
in each such case, the Holder hereof shall, upon the exercise of this Warrant,
be entitled to receive, in addition to the number of shares of Preferred Stock
receivable thereupon, and without payment of any additional consideration
therefor, the amount of stock and other securities and property (including cash
in the cases referred to in clause (b) above and this clause (c)) which such
Holder would hold on the date of such exercise had he been the holder of record
of such Preferred Stock as of the date on which holders of Preferred Stock
received or became entitled to receive such shares or all other additional stock
and other securities and property.

                  3.3 REORGANIZATION, RECLASSIFICATION, CONSOLIDATION, MERGER OR
SALE. If any recapitalization, reclassification or reorganization of the capital
stock of the Company, or any consolidation or merger of the Company with another
corporation, or the sale of all or substantially all of its assets or other
transaction shall be effected in such a way that holders of Preferred Stock
shall be entitled to receive stock, securities, or other assets or property (an
"ORGANIC CHANGE"), then, as a condition of such Organic Change, lawful and
adequate provisions shall be made by the Company whereby the Holder hereof shall
thereafter have the right to purchase and receive (in lieu of the shares of the
Preferred Stock of the Company immediately theretofore purchasable and
receivable upon the exercise of the rights represented hereby) such shares of
stock, securities or other assets or property as may be issued or payable with
respect to or in exchange for a number of outstanding shares of such Preferred
Stock equal to the number of shares of such stock immediately theretofore
purchasable and receivable upon the exercise of the rights represented hereby;
provided, however, that in the event the value of the stock, securities or other
assets or property (determined in good faith by the Board of Directors of the
Company) issuable or payable with respect to one share of the Preferred Stock of
the Company immediately theretofore purchasable and receivable upon the exercise
of the rights represented hereby is in excess of the Stock Purchase Price hereof
effective at the time of a merger and securities received in such
reorganization, if any, are publicly traded, then this Warrant shall expire
unless exercised prior to such Organic Change. In the event of any Organic
Change, appropriate provision shall be made by the Company with respect to the
rights and interests of the Holder of this Warrant to the end that the
provisions hereof (including, without limitation, provisions for adjustments of
the Stock Purchase Price and of the number of shares purchasable and receivable
upon the exercise of this Warrant) shall thereafter be applicable, in relation
to any shares of stock, securities or assets thereafter deliverable upon the
exercise hereof.

                  3.4 CERTAIN EVENTS. If any change in the outstanding Preferred
Stock of the Company or any other event occurs as to which the other provisions
of this Section 3 are not strictly applicable or if strictly applicable would
not fairly protect the purchase rights of the

                                       5.
<PAGE>

Holder of the Warrant in accordance with such provisions, then the Board of
Directors of the Company shall make an adjustment in the number and class of
shares available under the Warrant, the Stock Purchase Price or the application
of such provisions, so as to protect such purchase rights as aforesaid. The
adjustment shall be such as will give the Holder of the Warrant upon exercise
for the same aggregate Stock Purchase Price the total number, class and kind of
shares as he would have owned had the Warrant been exercised prior to the event
and had he continued to hold such shares until after the event requiring
adjustment.

                  3.5      NOTICES OF CHANGE.

                           (a) Immediately upon any adjustment in the number or
class of shares subject to this Warrant and of the Stock Purchase Price, the
Company shall give written notice thereof to the Holder, setting forth in
reasonable detail and certifying the calculation of such adjustment.

                           (b) The Company shall give written notice to the
Holder at least 5 business days prior to the date on which the Company closes
its books or takes a record for determining rights to receive any dividends or
distributions.

                           (c) The Company shall also give written notice to the
Holder at least 15 business days prior to the date on which an Organic Change
shall take place.

         4. ISSUE TAX. The issuance of certificates for shares of Preferred
Stock upon the exercise of the Warrant shall be made without charge to the
Holder of the Warrant for any issue tax (other than any applicable income taxes)
in respect thereof; provided, however, that the Company shall not be required to
pay any tax which may be payable in respect of any transfer involved in the
issuance and delivery of any certificate in a name other than that of the then
Holder of the Warrant being exercised.

         5. CLOSING OF BOOKS. The Company will at no time close its transfer
books against the transfer of any warrant or of any shares of Preferred Stock
issued or issuable upon the exercise of any warrant in any manner which
interferes with the timely exercise of this Warrant.

         6. NO VOTING OR DIVIDEND RIGHTS; LIMITATION OF LIABILITY. Nothing
contained in this Warrant shall be construed as conferring upon the Holder
hereof the right to vote or to consent or to receive notice as a stockholder of
the Company or any other matters or any rights whatsoever as a stockholder of
the Company. No dividends or interest shall be payable or accrued in respect of
this Warrant or the interest represented hereby or the shares purchasable
hereunder until, and only to the extent that, this Warrant shall have been
exercised. No provisions hereof, in the absence of affirmative action by the
holder to purchase shares of Preferred Stock, and no mere enumeration herein of
the rights or privileges of the holder hereof, shall give rise to any liability
of such Holder for the Stock Purchase Price or as a stockholder of the Company,
whether such liability is asserted by the Company or by its creditors.

                                       6.
<PAGE>

         7. WARRANTS TRANSFERABLE. Subject to compliance with applicable federal
and state securities laws, this Warrant and all rights hereunder are
transferable, in whole or in part, without charge to the holder hereof (except
for transfer taxes), upon surrender of this Warrant properly endorsed. Each
taker and holder of this Warrant, by taking or holding the same, consents and
agrees that this Warrant, when endorsed in blank, shall be deemed negotiable,
and that the holder hereof, when this Warrant shall have been so endorsed, may
be treated by the Company, at the Company's option, and all other persons
dealing with this Warrant as the absolute owner hereof for any purpose and as
the person entitled to exercise the rights represented by this Warrant, or to
the transfer hereof on the books of the Company any notice to the contrary
notwithstanding; but until such transfer on such books, the Company may treat
the registered owner hereof as the owner for all purposes.

         8. RIGHTS AND OBLIGATIONS SURVIVE EXERCISE OF WARRANT. The rights and
obligations of the Company, of the holder of this Warrant and of the holder of
shares of Preferred Stock issued upon exercise of this Warrant, shall survive
the exercise of this Warrant.

         9. MODIFICATION AND WAIVER. This Warrant and any provision hereof may
be changed, waived, discharged or terminated with the written consent of the
Company and holders of at least 66 2/3% in interest of the outstanding Loan
Amounts (as such term is defined in the Note and Warrant Purchase Agreement of
even date herewith, to which the Company and Holder are parties, INTER ALIA).
Holder acknowledges that because this Warrant may be amended with the consent of
such 66 2/3% in interest, Holder's rights hereunder may be amended or waived
without Holder's consent.

         10. NOTICES. Any notice, request or other document required or
permitted to be given or delivered to the holder hereof or the Company shall be
delivered or shall be sent by certified mail, postage prepaid, to each such
holder at its address as shown on the books of the Company or to the Company at
the address indicated therefor in the first paragraph of this Warrant or such
other address as either may from time to time provide to the other.

         11. BINDING EFFECT ON SUCCESSORS. This Warrant shall be binding upon
any corporation succeeding the Company by merger, consolidation or acquisition
of all or substantially all of the Company's assets. All of the obligations of
the Company relating to the Preferred Stock issuable upon the exercise of this
Warrant shall survive the exercise and termination of this Warrant. All of the
covenants and agreements of the Company shall inure to the benefit of the
successors and assigns of the holder hereof.

         12. DESCRIPTIVE HEADINGS AND GOVERNING LAW. The description headings of
the several sections and paragraphs of this Warrant are inserted for convenience
only and do not constitute a part of this Warrant. This Warrant shall be
construed and enforced in accordance with, and the rights of the parties shall
be governed by, the laws of the State of California.

         13. LOST WARRANTS. The Company represents and warrants to the Holder
hereof that upon receipt of evidence reasonably satisfactory to the Company of
the loss, theft, destruction, or mutilation of this Warrant and, in the case of
any such loss, theft or destruction, upon receipt of

                                       7.
<PAGE>

an indemnity reasonably satisfactory to the Company, or in the case of any such
mutilation upon surrender and cancellation of such Warrant, the Company, at its
expense, will make and deliver a new Warrant, of like tenor, in lieu of the
lost, stolen, destroyed or mutilated Warrant.

         14. FRACTIONAL SHARES. No fractional shares shall be issued upon
exercise of this Warrant. The Company shall, in lieu of issuing any fractional
share, pay the holder entitled to such fraction a sum in cash equal to such
fraction multiplied by the then effective Stock Purchase Price.

                                       8.
<PAGE>

         IN WITNESS WHEREOF, the Company has caused this Warrant to be duly
executed by its officers, thereunto duly authorized this 25th day of June, 1999.

                                              VERSICOR INC.,
                                              a Delaware corporation

                                              By:  /s/ GEORGE F. HORNER
                                                   -------------------------
                                                   George F. Horner
                                                   Chief Executive Officer

<PAGE>

                                    EXHIBIT A

                                SUBSCRIPTION FORM

                                                       Date:____________,19____

Versicor Inc.
34790 Ardentech Court
Fremont, California 94555
Attn: Chief Executive Officer

Ladies and Gentlemen:

/ /  The undersigned hereby elects to exercise the warrant issued to it by
     Versicor Inc. (the "Company") and dated June 25, 1999 Warrant No. PW-_____
     (the "Warrant") and to purchase thereunder ______________________ shares of
     the Series ____ Preferred Stock of the Company (the "Shares") at a purchase
     price of _________________________ Dollars ($____________) per Share or an
     aggregate purchase price of ___________________________ Dollars
     ($__________) (the "Purchase Price").

/ /  The undersigned hereby elects to convert _____________________________
     percent (________%) of the value of the Warrant pursuant to the provisions
     of Section 1.2 of the Warrant.

         Pursuant to the terms of the Warrant the undersigned has delivered the
Purchase Price herewith in full in cash or by certified check or wire transfer.

                                            Very truly yours,

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

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