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                                                                   EXHIBIT 10.45


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                                 RIBOGENE, INC.



                           LOAN AND SECURITY AGREEMENT

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      This LOAN AND SECURITY AGREEMENT (this "Agreement") is entered into as of
December 24, 1998, by and between VENTURE BANKING GROUP, a division of Cupertino
National Bank ("Bank") and RIBOGENE, INC. ("Borrower").


                                    RECITALS

      Borrower wishes to obtain credit from Bank, and Bank desires to continue
to extend credit to Borrower. This Agreement sets forth the terms on which Bank
will advance credit to Borrower, and Borrower will repay the amounts owing to
Bank.


                                    AGREEMENT

         The parties agree as follows:

      1.    DEFINITIONS AND CONSTRUCTION

            1.1   Definitions.

                  As used in this Agreement, the following terms shall have the
following definitions:

                  "Advance" or "Advances" means a cash advance under Section
2.1.

                  "Affiliate" means, with respect to any Person, any Person that
owns or controls directly or indirectly such Person, any Person that controls or
is controlled by or is under common control with such Person, and each of such
Person's senior executive officers, directors, partners and, for any Person that
is a limited liability company, such Persons, managers and members, provided
that for purposes of this Agreement, with respect to Borrower, Affiliate shall
mean only Borrower, Borrower's Subsidiaries and each of Borrower's and its
Subsidiaries senior executive officers, directors, partners and for any
subsidiary that is a limited liability company, such Subsidiary's managers and
members.

                  "Bank Expenses" means all reasonable costs or expenses
(including reasonable attorneys' fees and expenses) incurred in connection with
the preparation and negotiation of the Loan Documents; and Bank's reasonable
attorneys' fees and expenses incurred in amending, enforcing or defending the
Loan Documents (including fees and expenses of appeal or review, or those
incurred in any Insolvency Proceeding), whether or not suit is brought.

                  "Borrower's Books" means all of Borrower's books and records
including without limitation: ledgers; records concerning Borrower's assets or
liabilities, the Collateral, business operations or financial condition; and all
computer programs, or tape files, and the equipment, containing such
information.

                  "Business Day" means any day that is not a Saturday, Sunday,
or other day on which banks in the State of California are authorized or
required to close.

                  "Closing Date" means the date of this Agreement.

                  "Code" means the California Uniform Commercial Code.

                  "Collateral" means the property described on Exhibit A
attached hereto.


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                  "Credit Extension" means each Advance or any other extension
of credit by Bank for the benefit of Borrower hereunder.

                  "Default Rate" has the meaning assigned in Section 2.3((b)).

                  "GAAP" means generally accepted accounting principles as in
effect in the United States from time to time.

                  "Insolvency Proceeding" means any proceeding commenced by or
against any person or entity under any provision of the United States Bankruptcy
Code, as amended, or under any other bankruptcy or insolvency law, including
assignments for the benefit of creditors, formal or informal moratoria,
compositions, extension generally with its creditors, or proceedings seeking
reorganization, arrangement, or other relief.

                  "IRC" means the Internal Revenue Code of 1986, as amended, and
the regulations thereunder.

                  "Lien" means any mortgage, lien, deed of trust, charge,
pledge, security interest or other encumbrance.

                  "Loan Documents" means, collectively, this Agreement, any note
or notes executed by Borrower, and any other present or future agreement entered
into between Borrower and/or for the benefit of Bank in connection with this
Agreement, all as amended, extended or restated from time to time.

                  "Material Adverse Effect" means a material adverse effect on
(i) the business operations or condition (financial or otherwise) of Borrower
and its Subsidiaries taken as a whole or (ii) the ability of Borrower to repay
the Obligations or otherwise perform its obligations under the Loan Documents.

                  "Maturity Date" means the third anniversary of the Closing
Date.

                  "Obligations" means all debt, principal, interest, Bank
Expenses and other amounts owed to Bank by Borrower pursuant to this Agreement
or any other agreement, whether absolute or contingent, due or to become due,
now existing or hereafter arising, including any interest that accrues after the
commencement of an Insolvency Proceeding and including any debt, liability, or
obligation owing from Borrower to others that Bank may have obtained by
assignment or otherwise.

                  "Payment Date" means the last calendar day of each month,
commencing on the first such date after the Closing Date and ending on the
Maturity Date.

                  "Permitted Indebtedness" means:

                  (a)   Indebtedness of Borrower in favor of Bank arising under
this Agreement or any other Loan Document;

                  (b)   Indebtedness existing on the Closing Date and disclosed
in the Schedule;

                  (c)   Indebtedness to trade creditors and with respect to
surety bonds and similar obligations incurred in the ordinary course of
business;

                  (d)   Subordinated Debt;

                  (e)   Indebtedness of Borrower to any Subsidiary and
Contingent Obligations of any Subsidiary with respect to obligations of Borrower
(provided that the primary obligations are not prohibited 


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hereby), and Indebtedness of any Subsidiary to any other Subsidiary and
Contingent Obligations of any Subsidiary with respect to obligations of any
other Subsidiary (provided that the primary obligations are not prohibited
hereby);

                  (f)   Indebtedness secured by Permitted Liens;

                  (g)   Capital leases or indebtedness incurred solely to
purchase equipment which is secured in accordance with clause (c) of "Permitted
Liens" below and is not in excess of the lesser of the purchase price of such
equipment or the fair market value of such equipment on the date of acquisition;
and

                  (h)   Extensions, refinancings, modifications, amendments and
restatements of any of items of Permitted Indebtedness (a) through (g) above,
provided that the principal amount thereof is not increased or the terms thereof
are not modified to impose more burdensome terms upon Borrower or its
Subsidiary, as the case may be.

                  "Permitted Liens" means the following:

                  (a)   Any Liens existing on the Closing Date and disclosed in
the Schedule or arising under this Agreement or the other Loan Documents;

                  (b)   Liens for taxes, fees, assessments or other governmental
charges or levies, either not delinquent or being contested in good faith by
appropriate proceedings and as to which adequate reserves are maintained on
Borrower's Books in accordance with GAAP, provided the same have no priority
over any of Bank's security interests;

                  (c)   Liens (i) upon or in any Equipment acquired or held by
Borrower or any of its Subsidiaries to secure the purchase price of such
Equipment or indebtedness incurred solely for the purpose of financing the
acquisition of such Equipment, or (ii) existing on such equipment at the time of
its acquisition, provided that the Lien is confined solely to the property so
acquired and improvements thereon, and the proceeds of such Equipment;

                  (d)   Liens on Equipment leased by Borrower or any Subsidiary
pursuant to an operating or capital lease in the ordinary course of business
(including proceeds thereof and accessions thereto) incurred solely for the
purpose of financing the lease of such Equipment;

                  (e)   Leases or subleases and licenses or sublicenses granted
to others in the ordinary course of Borrower's business not interfering in any
material respect with the business of Borrower and its Subsidiaries taken as a
whole, and any interest or title of a lessor, licensor or under any lease or
license, provided that such leases, subleases, licenses and sublicenses do not
prohibit the grant of the security interest granted hereunder;

                  (f)   Liens incurred in connection with the extension, renewal
or refinancing of the indebtedness secured by Liens of the type described in
clauses (a) through (d) above, provided that any extension, renewal or
replacement Lien shall be limited to the property encumbered by the existing
Lien and the principal amount of the indebtedness being extended, renewed or
refinanced does not increase.

                  "Person" means any individual, sole proprietorship,
partnership, limited liability company, joint venture, trust, unincorporated
organization, association, corporation, institution, public benefit corporation,
firm, joint stock company, estate, entity or governmental agency.

                  "Prime Rate" means the variable rate of interest, per annum,
most recently published in the Western Edition of The Wall Street Journal, as
the "prime rate," whether or not such rate is the lowest rate available from
Bank.


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                  "Responsible Officer" means each of the Chief Executive
Officer, President, Chief Financial Officer and Controller of Finance of
Borrower.

                  "Schedule" means the schedule of exceptions attached hereto,
if any.

                  "Subordinated Debt" means any debt incurred by Borrower that
is subordinated to the debt owing by Borrower to Bank on terms acceptable to
Bank (and identified as being such by Borrower and Bank).

                  "Subsidiary" means with respect to any Person, corporation,
partnership, company association, joint venture, or any other business entity of
which more than fifty percent (50%) of the voting stock or other equity
interests is owned or controlled, directly or indirectly, by such Person or one
or more Affiliates of such Person.

                  "Tangible Net Worth" means, as of any applicable date, the
consolidated total assets of Borrower and its Subsidiaries minus, without
duplication, (i) the sum of any amounts attributable to (a) goodwill, (b)
intangible items such as unamortized debt discount and expense, patents, trade
and service marks and names, copyrights and research and development expenses
except prepaid expenses, and (c) all reserves not already deducted from assets,
and (ii) Total Liabilities.

                  "Term Loan Amount" means Five Million Dollars ($5,000,000).

                  "Total Liabilities" means, as of any applicable date, all
obligations that should, in accordance with GAAP, be classified as liabilities
on the consolidated balance sheet of Borrower, including in any event all
Indebtedness, but specifically excluding Subordinated Debt.

            1.2   Accounting and Other Terms.

                  All accounting terms not specifically defined herein shall be
construed in accordance with GAAP and all calculations and determinations made
hereunder shall be made in accordance with GAAP. When used herein, the term
"financial statements" shall refer to the financial statements of Borrower
prepared on a separate company basis and shall include the notes and schedules
thereto. The terms "including" / "includes" shall always be read as meaning
"including (or includes) without limitation," when used herein or in any other
Loan Document.

      2.    LOAN AND TERMS OF PAYMENT

            2.1   Advance.

                  (a)   Subject to and upon the terms and conditions of this
Agreement, Bank agrees to make an Advance to Borrower on the Closing Date in an
amount not to exceed the Term Loan Amount. The Advance shall be used for
transaction expenses, working capital, capital expenditures, and other lawful
corporate purposes. The Advance, to the extent repaid, may not be reborrowed.
Borrower shall deliver to Bank a promissory note in substantially the form of
Exhibit C hereto.

                  (b)   Interest shall accrue from the date of the Advance at
the rate specified in Section 2.3((a)), and shall be payable monthly for each
month through the Maturity Date.

                  (c)   The Advance and any other amounts due under this
Agreement shall be immediately due and payable on the Maturity Date. The Advance
may be prepaid at any time without premium or penalty.


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            2.2   Reserved.

            2.3   Interest Rates, Payments, and Calculations.

                  (a)   Interest Rate. Except as set forth in Section 2.3((b)),
the Advance shall bear interest on the average daily balance thereof, at a per
annum rate equal to the Prime Rate plus 0.50%.

                  (b)   Default Rate. All Obligations shall bear interest, from
and after the occurrence of an Event of Default, at a rate equal to five (5)
percentage points above the interest rate applicable immediately prior to the
occurrence of the Event of Default.

                  (c)   Payments. Interest hereunder shall be due and payable on
each Payment Date and on the Maturity Date. Borrower hereby authorizes Bank to
debit any accounts with Bank, including, without limitation, Account Number
______________ for payments of principal and interest due on the Obligations and
any other amounts owing by Borrower to Bank. Bank will notify Borrower of all
debits which Bank has made against Borrower's accounts. Any such debits against
Borrower's accounts in no way shall be deemed a set-off. Any interest not paid
when due shall be compounded by becoming a part of the Obligations, and such
interest shall thereafter accrue interest at the rate then applicable hereunder.

                  (d)   Computation. All interest chargeable under the Loan
Documents shall be computed on the basis of a three hundred sixty (360) day year
for the actual number of days elapsed.

            2.4   Crediting Payments.

                  Prior to the occurrence of an Event of Default, Bank shall
credit a wire transfer of funds, check or other item of payment to such deposit
account or Obligation as Borrower specifies. After the occurrence of an Event of
Default, the receipt by Bank of any wire transfer of funds, check, or other item
of payment, whether directed to Borrower's deposit account with Bank or to the
Obligations or otherwise, shall be immediately applied to conditionally reduce
Obligations, but shall not be considered a payment in respect of the Obligations
unless such payment is of immediately available federal funds or unless and
until such check or other item of payment is honored when presented for payment.
Notwithstanding anything to the contrary contained herein, any wire transfer or
payment received by Bank after 12:00 noon Pacific time shall be deemed to have
been received by Bank as of the opening of business on the immediately following
Business Day. Whenever any payment to Bank under the Loan Documents would
otherwise be due (except by reason of acceleration) on a date that is not a
Business Day, such payment shall instead be due on the next Business Day, and
additional fees or interest, as the case may be, shall accrue and be payable for
the period of such extension.

            2.5   Fees.

                  Borrower shall pay to Bank the following:

                  (a)   Facility Fee. A Facility Fee equal to Fifty Thousand
Dollars ($50,000), which fee shall be due on the Closing Date and shall be fully
earned and non-refundable;

                  (b)   Bank Expenses. Upon demand from Bank, including, without
limitation, upon the date hereof, all Bank Expenses incurred through the date
hereof, including reasonable attorneys' fees and expenses and, after the date
hereof, all Bank Expenses, including reasonable attorneys' fees and expenses, as
and when they become due.


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            2.6   Additional Costs.

                  In case any law, regulation, treaty or official directive or
the interpretation or application thereof by any court or any governmental
authority charged with the administration thereof or the compliance with any
guideline or request of any central bank or other governmental authority
(whether or not having the force of law):

                  (a)   subjects Bank to any tax with respect to payments of
principal or interest or any other amounts payable hereunder by Borrower or
otherwise with respect to the transactions contemplated hereby (except for taxes
on the overall net income of Bank imposed by the United States of America or any
political subdivision thereof);

                  (b)   imposes, modifies or deems applicable any deposit
insurance, reserve, special deposit or similar requirement against assets held
by, or deposits in or for the account of, or loans by, Bank; or

                  (c)   imposes upon Bank any other condition with respect to
its performance under this Agreement,

and the result of any of the foregoing is to increase the cost to Bank, reduce
the income receivable by Bank or impose any expense upon Bank with respect the
Obligations, Bank shall notify Borrower thereof. Borrower agrees to pay to Bank
the amount of such increase in cost, reduction in income or additional expense
as and when such cost, reduction or expense is incurred or determined, upon
presentation by Bank of a statement of the amount and setting forth Bank's
calculation thereof, all in reasonable detail, which statement shall be deemed
true and correct absent manifest error.

            2.7   Term.

                  Except as otherwise set forth herein, this Agreement shall
become effective on the Closing Date and, subject to Section 12.7, shall
continue in full force and effect for a term ending on the Maturity Date.
Notwithstanding the foregoing, Bank shall have the right to terminate its
obligation to make Credit Extensions under this Agreement immediately and
without notice upon the occurrence and during the continuance of an Event of
Default. Notwithstanding termination of this Agreement, Bank's lien on the
Collateral shall remain in effect for so long as any Obligations are
outstanding.

      3.    CONDITIONS OF CREDIT EXTENSIONS

            3.1   Conditions Precedent to Advance.

                  The obligation of Bank to make the Advance is subject to the
condition precedent that Bank shall have received, in form and substance
satisfactory to Bank, the following:

                  (a)   this Agreement;

                  (b)   a certificate of the Secretary of Borrower with respect
to certificate of incorporation, bylaws, incumbency and resolutions authorizing
the execution and delivery of this Agreement;

                  (c)   a promissory note evidencing Borrower's indebtedness to
Bank in substantially the form as Exhibit C hereto;

                  (d)   payment of the fees and Bank Expenses then due specified
in Section 2.5 hereof;


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                  (e)   financing statement (Form UCC-1);

                  (f)   such other documents, and completion of such other
matters, as Bank may reasonably deem necessary or appropriate.

            3.2   Further Conditions Precedent to Advance.

                  The obligation of Bank to make the Advance is further subject
to the following conditions:

                  (a)   the representations and warranties contained in Section
5 shall be true and correct in all material respects on and as of the date of
such Advance as though made at and as of each such date, and no Event of Default
shall have occurred and be continuing, or would result from such Advance. The
making of each Credit Extension shall be deemed to be a representation and
warranty by Borrower on the date of such Credit Extension as to the accuracy of
the facts referred to in this Section 3.2(a).

      4.    CREATION OF SECURITY INTEREST

            4.1   Grant of Security Interest.

                  Borrower grants and pledges to Bank a continuing security
interest in all presently existing and hereafter acquired or arising Collateral
in order to secure prompt payment of any and all Obligations and in order to
secure prompt performance by Borrower of each of its covenants and duties under
the Loan Documents. Except as set forth in the Schedule, such security interest
constitutes a valid, first priority security interest in the presently existing
Collateral, and will constitute a valid, first priority security interest in
Collateral acquired after the date hereof.

            4.2   Delivery of Additional Documentation Required.

                  Borrower shall from time to time execute and deliver to Bank,
at the request of Bank, all Negotiable Collateral, all financing statements and
other documents that Bank may reasonably request, in form satisfactory to Bank,
to perfect and continue perfected Bank's security interests in the Collateral
and in order to fully consummate all of the transactions contemplated under the
Loan Documents.

            4.3   Right to Inspect.

                  Bank (through any of its officers, employees, or agents) shall
have the right, upon reasonable prior notice, from time to time during
Borrower's usual business hours, to inspect Borrower's Books and to make copies
thereof and to check, test, and appraise the Collateral in order to verify
Borrower's financial condition or the amount, condition of, or any other matter
relating to, the Collateral.

      5.    REPRESENTATIONS AND WARRANTIES

            Borrower represents and warrants as follows:

            5.1   Due Organization and Qualification.

                  Borrower and each Subsidiary is a corporation duly existing
and in good standing under the laws of its state of incorporation and qualified
and licensed to do business in, and is in good standing in, any state in which
the conduct of its business or its ownership of property requires that it be so
qualified, except for states as to which any failure to so qualify would have
not have a Material Adverse Effect.


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            5.2   Due Authorization; No Conflict.

                  The execution, delivery, and performance of the Loan Documents
are within Borrower's powers, have been duly authorized, and are not in conflict
with nor constitute a breach of any provision contained in Borrower's
Certificate of Incorporation or Bylaws, nor will they constitute an event of
default under any material agreement to which Borrower is a party or by which
Borrower is bound. Borrower is not in default under any agreement to which it is
a party or by which it is bound, which default would reasonably be expected to
have a Material Adverse Effect.

            5.3   No Prior Encumbrances.

                  Borrower has good and indefeasible title to the Collateral,
free and clear of Liens.

            5.4   Name; Location of Chief Executive Office.

                  Except as disclosed in the Schedule, Borrower has not done
business and will not, without at least thirty (30) days prior written notice to
Bank, do business under any name other than that specified on the signature page
hereof. The chief executive office of Borrower is located at the address
indicated in Section 10 hereof.

            5.5   Litigation.

                  Except as set forth in the Schedule, there are no actions or
proceedings pending or, to Borrower's knowledge, threatened by or against
Borrower or any Subsidiary before any court or administrative agency in which an
adverse decision could have a Material Adverse Effect or a material adverse
effect on Borrower's interest or Bank's security interest in the Collateral.

            5.6   No Material Adverse Change in Financial Statements.

                  All consolidated financial statements related to Borrower and
any Subsidiary that have been delivered by Borrower to Bank fairly present in
all material respects Borrower's consolidated financial condition as of the date
thereof and Borrower's consolidated results of operations for the period then
ended. There has not been a material adverse change in the consolidated
financial condition of Borrower since the date of the most recent of such
financial statements submitted to Bank on or about the Closing Date.

            5.7   Solvency.

                  Borrower is solvent and Borrower is able to pay its debts
(including trade debts) as they mature.

            5.8   Regulatory Compliance.

                  Borrower and each Subsidiary has met the minimum funding
requirements of ERISA with respect to any employee benefit plans subject to
ERISA. No event has occurred resulting from Borrower's failure to comply with
ERISA that is reasonably likely to result in Borrower's incurring any liability
that could have a Material Adverse Effect. Borrower is not an "investment
company" or a company "controlled" by an "investment company" within the meaning
of the Investment Company Act of 1940. Borrower is not engaged principally, or
as one of its important activities, in the business of extending credit for the
purpose of purchasing or carrying margin stock (within the meaning of
Regulations G, T and U of the Board of Governors of the Federal Reserve System).
Borrower has complied with all the provisions of the Federal Fair Labor
Standards Act. Borrower has not violated any statutes, laws, ordinances or rules
applicable to it, violation of which could have a Material Adverse Effect.


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            5.9   Environmental Condition.

                  None of Borrower's or any Subsidiary's properties or assets
has ever been used by Borrower or any Subsidiary or, to the best of Borrower's
knowledge, by previous owners or operators, in the disposal of, or to produce,
store, handle, treat, release, or transport, any hazardous waste or hazardous
substance other than in accordance with applicable law; to the best of
Borrower's knowledge, none of Borrower's properties or assets has ever been
designated or identified in any manner pursuant to any environmental protection
statute as a hazardous waste or hazardous substance disposal site, or a
candidate for closure pursuant to any environmental protection statute; no lien
arising under any environmental protection statute has attached to any revenues
or to any real or personal property owned by Borrower or any Subsidiary; and
neither Borrower nor any Subsidiary has received a summons, citation, notice, or
directive from the Environmental Protection Agency or any other federal, state
or other governmental agency concerning any action or omission by Borrower or
any Subsidiary resulting in the release or other disposition of hazardous waste
or hazardous substances into the environment.

            5.10  Taxes.

                  Borrower and each Subsidiary has filed or caused to be filed
all tax returns required to be filed on a timely basis, and has paid, or has
made adequate provision for the payment of, all taxes reflected therein.

            5.11  Government Consents.

                  Borrower and each Subsidiary has obtained all consents,
approvals and authorizations of, made all declarations or filings with, and
given all notices to, all governmental authorities that are necessary for the
continued operation of Borrower's business as currently conducted except where
any failure to do so would not reasonably be expected to have a Material Adverse
Effect.

            5.12  Full Disclosure.

                  No representation, warranty or other statement made by
Borrower in any certificate or written statement furnished to Bank contains any
untrue statement of a material fact or omits to state a material fact necessary
in order to make the statements contained in such certificates or statements not
misleading (it being recognized by Bank that the projections and forecasts
provided by Borrower are not to be viewed as facts and that actual results
during the period or periods covered by any such projections and forecasts may
differ from the projected or forecasted results).

      6.    AFFIRMATIVE COVENANTS

                  Borrower covenants and agrees that, until payment in full of
all outstanding Obligations, and for so long as Bank may have any commitment to
make a Credit Extension hereunder, Borrower shall do all of the following:

            6.1   Good Standing.

                  Borrower shall maintain its and each of its Subsidiaries'
corporate existence and good standing in its jurisdiction of incorporation and
maintain qualification in each jurisdiction in which the failure to so qualify
would reasonably be expected to have a Material Adverse Effect. Borrower shall
maintain, and shall cause each of its Subsidiaries to maintain, to the extent
consistent with prudent management of Borrower's business, in force all
licenses, approvals and agreements, the loss of which would reasonably be
expected to have a Material Adverse Effect.


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            6.2   Government Compliance.

                  Borrower shall meet, and shall cause each Subsidiary to meet,
the minimum funding requirements of ERISA with respect to any employee benefit
plans subject to ERISA. Borrower shall comply, and shall cause each Subsidiary
to comply, with all statutes, laws, ordinances and government rules and
regulations to which it is subject, noncompliance with which could have a
Material Adverse Effect or a material adverse effect on the Collateral or the
priority of Bank's Lien on the Collateral.

            6.3   Financial Statements, Reports, Certificates.

                  Borrower shall deliver to Bank: (a) as soon as available, but
in any event within twenty (20) days after the end of each month, a company
prepared consolidated balance sheet and income statement covering Borrower's
consolidated operations during such period, in a form and certified by an
Officer of Borrower reasonably acceptable to Bank; (b) as soon as available, but
in any event within ninety (90) days after the end of Borrower's fiscal year,
audited consolidated financial statements of Borrower prepared in accordance
with GAAP, consistently applied, together with an unqualified opinion on such
financial statements of an independent certified public accounting firm
reasonably acceptable to Bank; (c) within five (5) days of filing, copies of all
statements, reports and notices sent or made available generally by Borrower to
its security holders or to any holders of Subordinated Debt and all reports on
Form 10-K, 10-Q and 8-K filed with the Securities and Exchange Commission; (d)
promptly upon receipt of notice thereof, a report of any legal actions pending
or threatened against Borrower or any Subsidiary that could result in damages or
costs to Borrower or any Subsidiary of One Hundred Thousand Dollars ($100,000)
or more; and (e) such budgets, sales projections, operating plans or other
financial information as Bank may reasonably request from time to time.

                           Within twenty (20) days after the last day of each
month, Borrower shall deliver to Bank with the monthly financial statements a 
Compliance Certificate signed by a Responsible Officer in substantially the form
of Exhibit B hereto.

            6.4   Taxes.

                  Borrower shall make, and shall cause each Subsidiary to make,
due and timely payment or deposit of all material federal, state, and local
taxes, assessments, or contributions required of it by law, and will execute and
deliver to Bank, on demand, appropriate certificates attesting to the payment or
deposit thereof.

            6.5   Principal Depository.

                  Borrower shall maintain its principal depository and operating
accounts with Bank. Borrower shall at all times hold not less than Five Million
Dollars ($5,000,000) in one or more certificates of deposit or other deposit
accounts at Bank.

            6.6   Insurance.

                  (a)   Borrower, at its expense, shall keep its properties
insured against loss or damage by fire, theft, explosion, sprinklers, and all
other hazards and risks, and in such amounts, as ordinarily insured against by
other owners in similar businesses conducted in the locations where Borrower's
business is conducted on the date hereof. Borrower shall also maintain insurance
relating to Borrower's ownership and use of the properties in amounts and of a
type that are customary to businesses similar to Borrower's.

                  (b)   All such policies of insurance shall be in such form,
with such companies, and in such amounts as are reasonably satisfactory to Bank.
All such policies of property insurance shall contain a lender's loss payable
endorsement, in a form satisfactory to Bank, showing Bank as an additional loss
payee thereof and all liability insurance policies shall show the Bank as an
additional insured, and shall specify that the insurer 


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must give at least twenty (20) days notice to Bank before canceling its policy
for any reason. At Bank's request, Borrower shall deliver to Bank certified
copies of such policies of insurance and evidence of the payments of all
premiums therefor. All proceeds payable under any such policy shall, at the
option of Bank, be payable to Bank to be applied on account of the Obligations.

            6.7   Liquidity.

                  Borrower shall maintain, as of the last day of each calendar
month, a Liquidity Ratio of at least 2.0 to 1.0. For purposes of this Section,
"Liquidity Ratio" means as of any date for which it is tested, the ratio of (a)
an amount equal to (i) cash and cash equivalents to (b) the outstanding
principal amount of the Advance.

            6.8   Tangible Net Worth.

                  Borrower shall maintain, as of the last day of each calendar
month, a Tangible Net Worth of not less than Ten Million Dollars ($10,000,000).

            6.9   Debt-Net Worth Ratio.

                  Borrower shall maintain, as of the last day of each calendar
month, a ratio of Total Liabilities less Subordinated Debt to Tangible Net Worth
plus Subordinated Debt of not more than 1.0 to 1.0.

            6.10  Year 2000.

                  Borrower and its Subsidiaries have reviewed the areas within
their business and operations which could be adversely affected by, and have
developed or are developing a program to address on a timely basis, the risk
that certain computer applications used by the Borrower or its Subsidiaries (or
any of their respective material suppliers, customers or vendors) may be unable
to recognize and perform properly date-sensitive functions involving dates prior
to and after December 31, 1999 (the "Year 2000 Problem"). Borrower shall perform
all acts as shall be reasonably necessary to ensure that the Year 2000 Problem
will not result in any Material Adverse Effect.

            6.11  Further Assurances.

                  At any time and from time to time Borrower shall execute and
deliver such further instruments and take such further action as may reasonably
be requested by Bank to effect the purposes of this Agreement.

      7.    NEGATIVE COVENANTS

                  Borrower covenants and agrees that, so long as any Credit
Extension hereunder shall be available and until payment in full of the
outstanding Obligations or for so long as Bank may have any commitment to make
any Advances, Borrower will not do any of the following:

            7.1   Dispositions.

                  Convey, sell, lease, transfer or otherwise dispose of
(collectively, a "Transfer"), or permit any of its Subsidiaries to Transfer, all
or any part of its business or property, other than Transfers (i) of inventory
in the ordinary course of business, (ii) of non-exclusive licenses and similar
arrangements for the use of the property of Borrower in the ordinary course of
business, (iii) of worn-out or obsolete Equipment, or (iv) of research and
development arrangements in the ordinary course of business.


                                       11
<PAGE>   13
            7.2   Changes in Business, Ownership, Management or Business
Locations.

                  Engage in any business, or permit any of its Subsidiaries to
engage in any business, other than the businesses currently engaged in by
Borrower and its Subsidiaries and any business substantially similar or related
thereto (or incidental thereto), or suffer a material change in Borrower's
ownership or management. Borrower will not, without at least thirty (30) days
prior written notification to Bank, relocate its chief executive office.

            7.3   Distributions.

                  Pay any dividends or make any other distribution or payment on
account of or in redemption, retirement or purchase of any capital stock.

            7.4   Mergers or Acquisitions.

                  Merge or consolidate, or permit any of its Subsidiaries to
merge or consolidate, with or into any other business organization, or acquire,
or permit any of its Subsidiaries to acquire, all or substantially all of the
capital stock or property of another Person, except where Borrower is the
surviving entity.

            7.5   Transactions with Affiliates.

                  Directly or indirectly enter into any material transaction
with any Affiliate of Borrower except for transactions that are in the ordinary
course of Borrower's business, upon fair and reasonable terms that are no less
favorable to Borrower than would be obtained in an arm's length transaction with
a non-affiliated Person.

            7.6   Subordinated Debt.

                  Make any payment in respect of any Subordinated Debt, or
permit any of its Subsidiaries to make any such payment, except in compliance
with the terms of such Subordinated Debt, or amend any provision contained in
any documentation relating to the Subordinated Debt without Bank's prior written
consent.

            7.7   Compliance.

                  Become an "investment company" or a company controlled by an
"investment company," within the meaning of the Investment Company Act of 1940,
or become principally engaged in, or undertake as one of its important
activities, the business of extending credit for the purpose of purchasing or
carrying margin stock, or use the proceeds of any Advance for such purpose; fail
to meet the minimum funding requirements of ERISA, permit a Reportable Event or
Prohibited Transaction, as defined in ERISA, to occur; fail to comply with the
Federal Fair Labor Standards Act or violate any other law or regulation, which
violation could have a Material Adverse Effect or a material adverse effect on
the Collateral or the priority of Bank's Lien on the Collateral, or permit any
of its Subsidiaries to do any of the foregoing.

            7.8   Indebtedness.

                  Create, incur, assume or be or remain liable with respect to
any Indebtedness, or permit any Subsidiary so to do, other than Permitted
Indebtedness.


                                       12
<PAGE>   14
            7.9   Encumbrances.

                  Create, incur, assume or suffer to exist any Lien with respect
to any of its property, or assign or otherwise convey any right to receive
income, including the sale of any accounts receivable, or permit any of its
Subsidiaries so to do, except for Permitted Liens.

      8.    EVENTS OF DEFAULT

                  Any one or more of the following events shall constitute an
Event of Default by Borrower under this Agreement:

            8.1   Payment Default.

                  If Borrower fails to pay, when due, any of the Obligations;

            8.2   Covenant Default.

                  (a)   If Borrower fails to perform any obligation under
Article 6 or violates any of the covenants contained in Article 7 of this
Agreement, or if Borrower fails or neglects to perform, keep, or observe any
other material term, provision, condition, covenant, or agreement contained in
this Agreement, in any of the Loan Documents, or in any other present or future
agreement between Borrower and Bank and as to any default under such other term,
provision, condition, covenant or agreement that can be cured, has failed to
cure such default within ten (10) days after the occurrence thereof; provided,
however, that if the default cannot by its nature be cured within the ten (10)
day period or cannot after diligent attempts by Borrower be cured within such
ten (10) day period, and such default is likely to be cured within a reasonable
time, then Borrower shall have an additional reasonable period (which shall not
in any case exceed an additional thirty (30) days) to attempt to cure such
default, and within such reasonable time period the failure to have cured such
default shall not be deemed an Event of Default (provided that no Credit
Extensions will be required to be made during such cure period);

            8.3   Material Adverse Change.

                  If there (i) occurs a material adverse change in the business,
operations, or condition (financial or otherwise) of Borrower or (ii) is a
material impairment of Borrower's ability to repay any portion of the
Obligations when and as due or (iii) is a material impairment of the value or
priority of Bank's security interests in the Collateral;

            8.4   Attachment.

                  If any material portion of Borrower's assets is attached,
seized, subjected to a writ or distress warrant, or is levied upon, or comes
into the possession of any trustee, receiver or person acting in a similar
capacity and such attachment, seizure, writ or distress warrant or levy has not
been removed, discharged or rescinded within thirty (30) days, or if Borrower is
enjoined, restrained, or in any way prevented by court order from continuing to
conduct all or any material part of its business affairs, or if a judgment or
other claim becomes a lien or encumbrance upon any material portion of
Borrower's assets, or if a notice of lien, levy, or assessment is filed of
record with respect to any of Borrower's assets by the United States Government,
or any department, agency, or instrumentality thereof, or by any state, county,
municipal, or governmental agency, and the same is not paid within thirty (30)
days after Borrower receives notice thereof, provided that none of the foregoing
shall constitute an Event of Default where such action or event is stayed or an
adequate bond has been posted pending a good faith contest by Borrower (provided
that no Credit Extensions will be required to be made during such cure period);


                                       13
<PAGE>   15
            8.5   Insolvency.

                  If Borrower becomes insolvent, or if an Insolvency Proceeding
is commenced by Borrower, or if an Insolvency Proceeding is commenced against
Borrower and is not dismissed or stayed within thirty (30) days (provided that
no Credit Extensions will be made from the date of commencement of an Insolvency
Proceeding up to the date of the dismissal of such Insolvency Proceeding);

            8.6   Subordinated Debt.

                  If Borrower makes any payment on account of Subordinated Debt,
except to the extent such payment is required pursuant to the terms of such
Subordinated Debt which Subordinated Debt has been approved by Bank or is
allowed under any subordination agreement entered into with Bank;

            8.7   Judgments.

                  If a judgment or judgments for the payment of money in an
amount, individually or in the aggregate, of at least One Hundred Thousand
Dollars ($100,000) shall be rendered against Borrower and shall remain
unsatisfied and unstayed for a period of twenty (20) days (provided that no
Credit Extensions will be made from the date of such judgment until to the
satisfaction or stay of such judgment); or

            8.8   Misrepresentations.

                  If any material misrepresentation or material misstatement
exists now or hereafter in any warranty or representation set forth herein or in
any certificate or writing delivered to Bank by any Responsible Officer pursuant
to this Agreement or to induce Bank to enter into this Agreement or any other
Loan Document.

      9.    BANK'S RIGHTS AND REMEDIES

            9.1   Rights and Remedies.

                  Upon the occurrence and during the continuance of an Event of
Default, Bank may, at its election, without notice of its election and without
demand, do any one or more of the following, all of which are authorized by
Borrower:

                  (a)   Declare all Obligations, whether evidenced by this
Agreement, by any of the other Loan Documents, or otherwise, immediately due and
payable (provided that upon the occurrence of an Event of Default described in
Section 8.5 all Obligations shall become immediately due and payable without any
action by Bank);

                  (b)   Cease advancing money or extending credit to or for the
benefit of Borrower under this Agreement or under any other agreement between
Borrower and Bank;

                  (c)   Liquidate or otherwise dispose of the Collateral and
apply any proceeds thereof to any Obligations; and

                  (d)   Without notice to Borrower set off and apply to the
Obligations any and all (i) balances and deposits of Borrower held by Bank, or
(ii) indebtedness at any time owing to or for the credit or the account of
Borrower held by Bank.


                                       14
<PAGE>   16
            9.2   Power of Attorney.

                  Effective only upon the occurrence and during the continuance
of an Event of Default, Borrower hereby irrevocably appoints Bank (and any of
Bank's designated officers, or employees) as Borrower's true and lawful attorney
to liquidate or otherwise dispose of the Collateral. The appointment of Bank as
Borrower's attorney in fact, and each and every one of Bank's rights and powers,
being coupled with an interest, is irrevocable until all of the Obligations have
been fully repaid and performed and Bank's obligation to provide Advances
hereunder is terminated.

            9.3   Remedies Cumulative.

                  Bank's rights and remedies under this Agreement, the Loan
Documents, and all other agreements shall be cumulative. Bank shall have all
other rights and remedies not expressly set forth herein as provided under the
Code, by law, or in equity. No exercise by Bank of one right or remedy shall be
deemed an election, and no waiver by Bank of any Event of Default on Borrower's
part shall be deemed a continuing waiver. No delay by Bank shall constitute a
waiver, election, or acquiescence by it. No waiver by Bank shall be effective
unless made in a written document signed on behalf of Bank and then shall be
effective only in the specific instance and for the specific purpose for which
it was given.

            9.4   Demand; Protest.

                  Borrower waives demand, protest, notice of protest, notice of
default or dishonor, notice of payment and nonpayment, notice of any default,
nonpayment at maturity, release, compromise, settlement, extension, or renewal
of accounts, documents, instruments, chattel paper, and guarantees at any time
held by Bank on which Borrower may in any way be liable.

            9.5   Intellectual Property Collateral.

                  Notwithstanding any other provisions of this Agreement, for so
long as no Event of Default has occurred, the security interest granted under
this Agreement in the Intellectual Property Collateral shall be deemed to extend
only to the cash and non-cash proceeds (including accounts and general
intangibles) arising from the disposition of all or any part of the Intellectual
Property Collateral, and Bank shall have no right to exercise any foreclosure
remedies, whether by sale, strict foreclosure or otherwise, with respect to
Intellectual Property Collateral other than with respect to such proceeds;
provided that this Section 15 shall have no further force or effect upon the
occurrence of an Event of Default or at any time thereafter. Upon the occurrence
of an Event of Default, Borrower agrees to execute and deliver to Bank an
Intellectual Property Security Agreement in form and content satisfactory to
Bank, and to execute such other documents and take such further action as may be
reasonably be requested by Bank to grant Bank a first priority perfected
security interest in the Intellectual Property Collateral.

      10.   NOTICES

                  Unless otherwise provided in this Agreement, all notices or
demands by any party relating to this Agreement or any other agreement entered
into in connection herewith shall be in writing and (except for financial
statements and other informational documents which may be sent by first-class
mail, postage prepaid) shall be personally delivered or sent by a recognized
overnight delivery service, by certified mail, postage prepaid, return receipt
requested, or by telefacsimile to Borrower or to Bank, as the case may be, at
its addresses set forth below:

      If to Borrower:                RiboGene, Inc.
                                     26118 Research Road
                                     Hayward, CA  94545
                                     Attn:  Chief Financial Officer


                                    15
<PAGE>   17
                                     FAX:  (510) 732-7741
      If to Bank:                    Venture Banking Group
                                     Three Palo Alto Square, Suite 150
                                     Palo Alto, CA  94306
                                     Attn:  Dan Pistone
                                     FAX:  (650) 843-6969

      The parties hereto may change the address at which they are to receive
notices hereunder, by notice in writing in the foregoing manner given to the
other.

      11.   CHOICE OF LAW AND VENUE

            The Loan Documents shall be governed by, and construed in accordance
with, the internal laws of the State of California, without regard to principles
of conflicts of law. Each of Borrower and Bank hereby submits to the exclusive
jurisdiction of the state and Federal courts located in the County of Santa
Clara, State of California. BORROWER AND BANK EACH HEREBY WAIVE THEIR RESPECTIVE
RIGHTS TO A JURY TRIAL OF ANY CLAIM OR CAUSE OF ACTION BASED UPON OR ARISING OUT
OF ANY OF THE LOAN DOCUMENTS OR ANY OF THE TRANSACTIONS CONTEMPLATED THEREIN,
INCLUDING CONTRACT CLAIMS, TORT CLAIMS, BREACH OF DUTY CLAIMS, AND ALL OTHER
COMMON LAW OR STATUTORY CLAIMS. EACH PARTY RECOGNIZES AND AGREES THAT THE
FOREGOING WAIVER CONSTITUTES A MATERIAL INDUCEMENT FOR IT TO ENTER INTO THIS
AGREEMENT. EACH PARTY REPRESENTS AND WARRANTS THAT IT HAS REVIEWED THIS WAIVER
WITH ITS LEGAL COUNSEL AND THAT IT KNOWINGLY AND VOLUNTARILY WAIVES ITS JURY
TRIAL RIGHTS FOLLOWING CONSULTATION WITH LEGAL COUNSEL.

      12.   GENERAL PROVISIONS

            12.1  Successors and Assigns.

            This Agreement shall bind and inure to the benefit of the respective
successors and permitted assigns of each of the parties; provided, however, that
neither this Agreement nor any rights hereunder may be assigned by Borrower
without Bank's prior written consent, which consent may be granted or withheld
in Bank's sole discretion. Bank shall have the right without the consent of or
notice to Borrower to sell, transfer, negotiate, or grant participation in all
or any part of, or any interest in, Bank's obligations, rights and benefits
hereunder to any affiliate of Bank or the U.S. Federal Reserve. Bank shall have
the right, with the prior consent of Borrower, which consent shall not be
unreasonably withheld, to sell, transfer, negotiate, or grant participation in
all or any part of, or any interest in, Bank's obligations, rights and benefits
hereunder to any other financial institution, provided that such consent shall
not be required if an Event of Default has occurred and is continuing.

            12.2  Indemnification.

            Borrower shall indemnify, defend, protect and hold harmless Bank and
its officers, employees, and agents against: (a) all obligations, demands,
claims, and liabilities claimed or asserted by any other party in connection
with the transactions contemplated by the Loan Documents; and (b) all losses or
Bank Expenses in any way suffered, incurred, or paid by Bank as a result of or
in any way arising out of, following, or consequential to transactions between
Bank and Borrower whether under the Loan Documents, or otherwise (including
without limitation reasonable attorneys fees and expenses), except for losses
caused by Bank's gross negligence or willful misconduct.


                                       16
<PAGE>   18
            12.3  Time of Essence.

            Time is of the essence for the performance of all obligations set
forth in this Agreement.

            12.4  Severability of Provisions.

            Each provision of this Agreement shall be severable from every other
provision of this Agreement for the purpose of determining the legal
enforceability of any specific provision.

            12.5  Amendments in Writing, Integration.

            This Agreement cannot be amended or terminated except by a writing
signed by Borrower and Bank. All prior agreements, understandings,
representations, warranties, and negotiations between the parties hereto with
respect to the subject matter of this Agreement, if any, are merged into this
Agreement and the Loan Documents, provided that any financing statement
previously filed for the benefit of Bank continues to perfect the security
interest in the Collateral.

            12.6  Counterparts.

            This Agreement may be executed in any number of counterparts and by
different parties on separate counterparts, each of which, when executed and
delivered, shall be deemed to be an original, and all of which, when taken
together, shall constitute but one and the same Agreement.

            12.7  Survival.

            All covenants, representations and warranties made in this Agreement
shall continue in full force and effect so long as any Obligations remain
outstanding. The obligations of Borrower to indemnify Bank with respect to the
expenses, damages, losses, costs and liabilities described in Section 12.2 shall
survive until all applicable statute of limitations periods with respect to
actions that may be brought against Bank have run.

            12.8  Confidentiality.

            In handling any confidential information Bank shall exercise the
same degree of care that it exercises with respect to its own proprietary
information of the same types to maintain the confidentiality of any non-public
information thereby received or received pursuant to this Agreement except that
disclosure of such information may be made (i) to the subsidiaries or affiliates
of Bank in connection with their present or prospective business relations with
Borrower, (ii) to prospective transferees or purchasers of any interest in the
Advances, provided that they have entered into a comparable confidentiality
agreement in favor of Borrower and have delivered a copy to Borrower, (iii) as
required by law, regulations, rule or order, subpoena, judicial order or similar
order, (iv) as may be required in connection with the examination, audit or
similar investigation of Bank, and (v) as Bank may deem appropriate in
connection with the enforcement of its remedies hereunder. Confidential
information hereunder shall not include information that either (a) is in the
public domain or in the knowledge or possession of Bank when disclosed to Bank,
or becomes part of the public domain after disclosure to Bank through no fault
of Bank; or (b) is disclosed to Bank by a third party, provided Bank does not
have actual knowledge that such third party is prohibited from disclosing such
information.


                                       17
<PAGE>   19
      IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed as of the date first above written.


                                       RIBOGENE, INC.


                                       By: _____________________________________

                                       Title: __________________________________

                                       VENTURE BANKING GROUP, a division of
                                       Cupertino National Bank


                                       By: _____________________________________

                                       Title: __________________________________


                                       18