MORTGAGE

            THIS MORTGAGE ("Mortgage") is made October 8, 1996, between BIOPURE
CORPORATION, a Delaware corporation with offices at 11 Hurley Street, Cambridge,
Massachusetts 02141 ("Mortgagor"), and PHARMACIA & UPJOHN, INC., a Delaware
corporation with offices at 7000 Portage Road, Kalamazoo, Michigan 49001
("Mortgagee").

            WHEREAS, Mortgagor by its certain Promissory Note of even date
herewith ("Note") has evidenced its obligation to pay to Mortgagee the principal
sum of $9,000,000, with interest and certain other sums, all as more fully
therein provided;

            NOW THEREFORE, to secure the payment of all principal, interest and
other sums due or to become due under the Note, the Security Agreement dated the
date hereof between Mortgagor and Mortgagee (the "Security Agreement") or this
Mortgage (collectively, "Debt"), Mortgagor hereby grants, bargains, sells,
conveys, aliens, enfeoffs, confirms, releases, assigns, transfers, pledges and
mortgages unto Mortgagee, all and singular Mortgagor's rights, titles and
interests in and to the following (collectively, "Mortgaged Property"):

            ALL THOSE CERTAIN leasehold estates (collectively, the "Leasehold")
with respect to (1) that certain real property located in Middlesex County,
Massachusetts, more particularly described in Exhibit "A" attached hereto and
made a part hereof ("Spring Street Land"), which leasehold was created pursuant
to that certain Commercial Lease Agreement dated as of October 12, 1990, as
amended, between Tarvis Realty Trust and the Mortgagor ("Spring Street Lease")
which, or a notice of which, is recorded with the Middlesex South County
Registry of Deeds in Deed Book 20910, page 184, together with all Mortgagor's
rights, credits, deposits, options, privileges and interests under or pertaining
to the Spring Street Lease or the Spring Street Land; (2) that certain real
property located in Middlesex County, Massachusetts, more particularly described
in Exhibit "A" attached hereto and made a part hereof ("37-39 Hurley Street
Land"), which leasehold was created pursuant to that certain Commercial Lease
Agreement dated as of August 23, 1994, as amended, between Tarvis Realty Trust
and the Mortgagor ("37-39 Hurley Street Lease") which, or a notice of which, is
recorded with the Middlesex South County Registry of Deeds in Deed Book 24974,
page 599, together with all Mortgagor's rights, credits, deposits, options,
privileges and interests under or pertaining to the 37-39 Street Lease or the
37-39 Hurley Street Land; and (3) that certain real property located in
Middlesex County, Massachusetts, more particularly described in Exhibit "A"
attached hereto and made a part hereof ("31-35 Hurley Street Land" and together
with the Spring Street Land and the 37-39 Hurley Street Land, the "Land"), which
leasehold was created pursuant to that certain Ground Lease Agreement dated as
of May 10, 1994, as amended, between Tarvis Realty Trust and the Mortgagor
("31-35 Hurley Street Lease" and together with the Spring Street Lease and the
37-39 Hurley Street
<PAGE>   3

Lease, the "Base Lease") which, or a notice of which, is recorded with the
Middlesex South County Registry of Deeds in Deed Book      , page     , together
with all Mortgagor's rights, credits, deposits, options, privileges and
interests under or pertaining to the 31-35 Street Lease or the 31-35 Hurley
Street Land;

            TOGETHER WITH any and all (a) buildings, structures, fixtures and
improvements now or hereafter located or erected on the Land ("Improvements";
the Leasehold, Land and Improvements are sometimes herein collectively referred
to as "Real Estate"), (b) passages, ways, water courses, easements, rights,
estates, interests, liberties, privileges, tenements, issues, proceeds,
products, profits, condemnation damages, proceeds of insurance, hereditaments
and appurtenances of every type and nature whatsoever to the Real Estate
belonging or appertaining, and claims or demands of any nature whatsoever of
Mortgagor either at law or in equity, in possession or expectancy, of, in and to
the Real Estate, (c) leases, subleases, contracts to lease and other agreements
relating to the use or occupancy of all or any part of the Real Estate now or
hereafter entered into by Mortgagor as landlord or sublandlord (collectively,
"Leases") and the rents, security deposits, issues and profits arising or
issuing therefrom ("Rents"), and (d) building materials, furniture, fixtures,
furnishings, fittings, apparatus, appliances, machinery, equipment, supplies,
inventory and personal property of every kind and nature whatsoever, now or
hereafter attached to, placed, installed or located upon, or used or useful in
any way with respect to, the Real Estate and all replacements thereof and
modifications and additions thereto and the proceeds and products thereof (all
of the things mentioned in this clause (d) being sometimes herein collectively
called "Personalty");

            TO HAVE AND TO HOLD the Mortgaged Property unto Mortgagee forever,
provided that if Mortgagor shall pay Mortgagee the Debt, and shall otherwise
perform all Mortgagor's covenants, agreements and obligations hereunder and
under the Note, then this Mortgage and the estate and interests hereby granted,
shall cease and be void; otherwise this Mortgage shall remain in full force and
effect.

            AND Mortgagor covenants and agrees with Mortgagee as follows:

            1. Payment of Debt. Mortgagor shall pay when due the Debt in the
manner provided in the Note, the Security Agreement and this Mortgage. The Debt
and each part thereof, if not paid when due, shall bear interest at the Default
Rate specified in the Note ("Default Rate") from the due date until paid in
full.

            2. Performance of Covenants. Mortgagor shall observe and perform
faithfully when due each and every obligation, covenant and agreement on
Mortgagor's part to be observed or performed under this Mortgage, the Security
Agreement or the Note.

             3. Title. Mortgagor represents and warrants to Mortgagee that: (a)
Mortgagor is and shall at all times remain the legal and beneficial owner of
good and


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<PAGE>   4

marketable indefeasible title to all of the Mortgaged Property, including
without limitation the Leasehold, (b) there is no limitation on the right of
Mortgagor to encumber the Mortgaged Property, and (c) this Mortgage is a good
and valid first lien on the Mortgaged Property, subject to no other mortgage,
lien, pledge, security interest or encumbrance. Mortgagor covenants to keep this
Mortgage a good and valid first lien on the Mortgaged Property at all times, and
shall warrant and forever defend the title to the Mortgaged Property unto the
Mortgagee against every person claiming or to claim the same or any part
thereof.

            4. Base Lease. The Mortgagor shall not sell, assign, modify, amend,
supplement, encumber or surrender the Base Lease without the prior written
consent of Mortgagee in each instance. Mortgagor shall promptly and fully keep,
perform and comply with all the terms, provisions, covenants, conditions and
agreements imposed upon or assumed by the Mortgagor as lessee under the Base
Lease and shall not do, or permit anything to be done, or omit from doing
anything, which will give the landlord under the Base Lease a right to terminate
the Base Lease. If the Mortgagor shall, in any manner, fail in this agreement,
Mortgagee may (but shall not be obligated to) take any action Mortgagee deems
necessary or desirable to prevent or cure any default by Mortgagor in the
performance of or compliance with any of Mortgagor's covenants or obligations
under the Base Lease. Mortgagee may rely on any notice of default received from
said landlord and may act thereon as herein provided even though the existence
of such default or the nature thereof may be questioned or denied by Mortgagor
or any party acting on behalf of Mortgagor, and such notice of default shall be
conclusive evidence that a default exists for the purpose of this Section.
Mortgagee shall have the right to enter upon the demised premises and any other
property owned or controlled by Mortgagor which is affected by any of the terms,
conditions, provisions, covenants and agreements of the Base Lease to such
extent and as often as Mortgagee, in its sole discretion, deems necessary or
desirable in order to prevent or cure and such default by Mortgagor. Mortgagee
may expend such sums of money as Mortgagee, in its sole discretion deems
necessary for any such purpose, and all sums so expended shall be deemed part of
the debt and shall be secured by this Mortgage.

            5. Fee Title. Mortgagor covenants that so long as any of the Debt
remains unpaid, the Leasehold shall not merge in or with the fee title or in or
with any other estate or interest in the Real Estate, but always shall be
complete, separate and distinct notwithstanding the occurrence of any event or
events by which the Leasehold may become vested in the same person in whom said
fee title is vested.

            6. Enforceability of Base Lease. Mortgagor represents and warrants
to Mortgagee that: (a) the Base Lease is valid, subsisting and all the terms
thereof are enforceable, (b) the rents and charges reserved in the Base Lease by
the landlord thereunder, to the extent now or heretofore payable, have been
fully paid and Mortgagor has no knowledge of any default thereunder by either
party thereto and (c) no delinquency exists in respect to the payment of any
tax, assessment, water or sewer rent or charge, or other governmental imposition
of any kind levied or assessed upon the Mortgaged Property.


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<PAGE>   5

            7. Security Agreement. (A) Without limiting any of the provisions of
this Mortgage, Mortgagor, as debtor, expressly grants to the Mortgagee, as
secured party, a security interest under the Massachusetts Uniform Commercial
Code ("UCC") in all and singular the Personalty and in any portion of the
balance of the Mortgaged Property which does not constitute real estate
(collectively, "Collateral").

            (B) In addition to and cumulative of other remedies granted in the
Loan Documents, Mortgagee may, upon the occurrence of any default by Mortgagor
hereunder, proceed under the UCC as to all or any part (as Mortgagee may elect)
of the Collateral, and shall have and may exercise with respect to the
Collateral all the rights, remedies and powers of a secured party under the UCC,
including, without limitation, the right to sell at public or private sale or
sales, or otherwise dispose of, lease or utilize the Collateral and any and all
parts thereof in any manner permitted under the UCC after default by a debtor,
and to apply the proceeds thereof toward payment of any costs and expenses
thereby incurred by Mortgagee, and toward payment of the Debt, in such order and
manner as Mortgagee may elect.

            (C) Among the rights of Mortgagee following a default by Mortgagor
hereunder, and without limitation thereto, Mortgagee shall have the right to
take possession of the Collateral and to enter upon any premises where same may
be situated for such purpose without being deemed guilty of trespass and without
liability for damages thereby occasioned, and to take any action deemed
necessary, appropriate or desirable by Mortgagee, to repair, refurbish or
otherwise prepare the Collateral for sale, lease or other use or disposition as
herein authorized.

            (D) To the extent permitted by law, Mortgagor expressly waives any
notice of sale or other disposition of the Collateral, and all other rights and
remedies of a debtor or procedures or formalities prescribed by law relative to
the sale or disposition of the Collateral or the exercise of any other right or
remedy of Mortgagee existing after a default by Mortgagor hereunder.

            (E) Mortgagee, upon a default by Mortgagor hereunder, is expressly
granted the right, at its option, to transfer at any time to itself or to its
nominee the Collateral, or any part or parts thereof, as Mortgagee may elect,
and to receive the monies, income, proceeds and benefits attributable or
accruing thereto, and to hold the same as security for the Debt or to apply it
in payment of the Debt, in such order or manner as Mortgagee may elect.

            (F) Should Mortgagee elect to exercise its rights under the
provisions of this Section as to part of the Collateral, such election shall not
preclude Mortgagee from exercising the rights and remedies granted by the other
provisions of this Mortgage or by law as to the remaining Collateral.


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<PAGE>   6

            (G) Mortgagee may, at its election, at any time after delivery of
this Mortgage, use and file executed counterparts hereof as financing statements
under the UCC.

            (H) So long as any of the Debt remains unpaid, Mortgagor shall not
execute and there shall not be filed in any public office any financing
statement or statements affecting the Collateral other than financing statements
in favor of Mortgagee hereunder.

            (I) Financing statements have been executed by the parties
simultaneously with the execution and delivery hereof, and are intended to be
forthwith filed and recorded in all appropriate filing and recording offices.
Mortgagee is authorized to file and record additional financing statements and
continuations thereof in each jurisdiction where Mortgagee deems it necessary or
desirable, and, at the request of Mortgagee, Mortgagor shall join Mortgagee in
executing one or more additional financing statements in form satisfactory to
Mortgagee, and will pay the cost of filing or recording such financing
statements or executed counterparts of this Mortgage, as financing statements,
in all public offices at any time and from time to time whenever such filing or
recording is deemed by Mortgagee to be necessary or desirable. Mortgagor shall
also pay the cost of filing or recording all such continuation statements deemed
by Mortgagee to be necessary or desirable.

            8. Insurance. (A) Mortgagor shall at all times keep the Mortgaged
Property insured for the protection of Mortgagee against such risks, and with
such coverages, as Mortgagee shall from time to time require, including without
limitation, broad form, comprehensive fire and extended coverage insurance, with
coverage for theft, vandalism and malicious mischief, for the full replacement
value of the Improvements, and rent insurance with respect to the Rents payable
for the one year period following the occurrence of a casualty. All insurance
policies required by this paragraph shall contain: (i) a "New York" or
"Massachusetts" form noncontributory mortgagee clause providing, among other
things, that any payment occasioned by loss thereunder shall be payable to the
holder of this Mortgage alone, and that Mortgagee shall not be subject to
defenses otherwise available to the insurer against the insured thereunder, (ii)
a waiver of subrogation as to Mortgagee's interest, (iii) a waiver of
co-insurance as to Mortgagee, and (iv) if requested by Mortgagee from time to
time, an "owner not in control" endorsement.

            (B) Mortgagor shall at all times maintain comprehensive general
public liability insurance, worker's compensation insurance and such other
liability insurance incident to the ownership of the Mortgaged Property as
Mortgagee may from time to time require. All insurance policies required by this
paragraph shall, at Mortgagee's election, name Mortgagee as a co-insured party.

            (C) If, at any time or from time to time, the Real Estate is located
in a designated "flood prone" area pursuant to the Flood Disaster Protection Act
of 1973, or any amendment or supplement thereto, then Mortgagor shall obtain
flood insurance and shall take such other action as may be necessary to comply
fully with the National Flood Insurance


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<PAGE>   7

Program set forth in said Act. Mortgagor shall comply fully with the National
Flood Insurance Act of 1968, as the same may be amended from time to time, and
all other laws, orders, rules, ordinances and regulations concerning flood
insurance, to the extent applicable to the Mortgaged Property.

            (D) Without limitation to the foregoing, the following provisions
shall apply to each and every policy of insurance which Mortgagor is hereby
required to carry: (i) the form, amount and coverage of each policy, and the
insurer under each policy, shall be subject to Mortgagee's approval, (ii)
Mortgagor shall cause each carrier thereof to deliver its certificate of
insurance to Mortgagee, certifying the applicable insurance provisions herein
required, (iii) within five days after Mortgagee's request, Mortgagor shall
deliver to Mortgagee an original copy of each policy, (iv) each policy shall
state that it has been prepaid by Mortgagor (or in lieu of such statement,
Mortgagor shall provide Mortgagee with evidence of such prepayment), and shall
require thirty (30) days' written notice by the carrier to Mortgagee prior to
any cancellation, expiration, amendment or lapse thereof, (v) no policy shall
name a loss payee or beneficiary other than Mortgagor and Mortgagee or any party
named as a loss payee or beneficiary on the date hereof, (vi) at least thirty
(30) days prior to the expiration of each policy, Mortgagor shall provide
Mortgagee with certificates (or copies of policies, if required by Mortgagee as
aforesaid) of renewal or replacement policies, (vii) each policy shall be issued
by a carrier duly licensed in the state in which the Real Estate is located,
(viii) in the event of loss, or an event which would constitute loss, under any
policy, Mortgagor shall give immediate notice thereof to Mortgagee, shall
promptly make proper proof of loss with the appropriate insurance carriers and
shall provide Mortgagee with copies of same, and Mortgagee may at its election
make proofs of loss if not made promptly by Mortgagor, and (ix) Mortgagee shall
have the right to retain and apply the proceeds of all insurance to restoration
or repair of the property damaged.

            (E) If the Mortgaged Property, or any part thereof, is destroyed or
damaged by any cause, Mortgagor shall as soon as possible, at Mortgagor's
expense and regardless of whether insurance proceeds shall be made available for
such purpose, restore, repair, replace and rebuild the Mortgaged Property as
nearly as possible to its value, condition and character immediately prior to
such damage, loss or destruction.

            9. Taxes. Mortgagor shall pay, before the same become delinquent,
all taxes, assessments and charges of every nature and by whomever assessed that
may now or hereafter be levied or assessed against, or that by reason of
nonpayment may become a lien upon, the Mortgaged Property, and Mortgagor shall
submit to Mortgagee evidence of the due and punctual payment thereof.

            10. Payment of Liens. Mortgagor shall pay at or prior to maturity
thereof, and in strict accordance with the terms thereof, any and all: (a)
claims, liens, encumbrances and sums which are or shall hereafter become or
appear to be an encumbrance, whether senior or subordinate hereto, upon the
Mortgaged Property or any part thereof or interest therein,


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<PAGE>   8

including but without limiting the generality of the foregoing, any and all
claims for work or labor performed, or materials or services supplied in
connection with any work upon the Mortgaged Property, and (b) claims, charges
and sums, the non-payment of which could result in a lien, claim or encumbrance
on the Mortgaged Property or which could confer upon a tenant of any part of the
Mortgaged Property a right to recover such claim, charge or sum as prepaid rent
or as a credit or offset against future rent. Mortgagor shall promptly furnish
to Mortgagee receipts evidencing all of the aforementioned payments.

            11. Condemnation. All awards made by any public or quasi-public
authority to the owners of the Mortgaged Property by virtue of an exercise of
the right of eminent domain are hereby mortgaged and assigned to Mortgagee, and
Mortgagee is hereby authorized, directed and empowered, at its option, to
collect and receive the proceeds of all such awards from the authorities making
the same and to give proper receipts and acquittances therefor. Mortgagee may,
at its election: (a) apply the net proceeds (i.e., after deducting Mortgagee's
costs of recovering same) of any such award to the discharge of the Debt whether
or not then due and payable, in whatever order and manner Mortgagee elects, or
(b) pay or make available to Mortgagor such net proceeds, upon such terms and
conditions as Mortgagee may elect.

            12. Collection of Rents. Mortgagor hereby irrevocably assigns the
Leases and Rents to Mortgagee and grants to Mortgagee the present and continuing
right, coupled with an interest, to collect the Rents and to enforce the Leases
and to enter and possess the Mortgaged Property for such purposes. However,
Mortgagee hereby conditionally waives such right, and grants to Mortgagor the
revocable license to collect and to enforce the same, provided, however, that
said waiver and license may, after a default by Mortgagor hereunder, be revoked
by Mortgagee at any time by giving notice of such revocation to Mortgagor. All
Rents collected by Mortgagor after a default shall have occurred hereunder shall
be held by Mortgagor as a trust fund for Mortgagee. Following such notice of
revocation, Mortgagee may retain and apply the Rents towards payment of the Debt
in such order and manner as Mortgagee may elect.

            13. Condition of Mortgaged Property. Mortgagor shall keep the
Mortgaged Property, and each part thereof, in good order and repair and in good,
safe, first class operating condition. Mortgagor shall make promptly when needed
all necessary repairs, renewals, replacements, additions and improvements to the
Mortgaged Property, and shall not allow the Mortgaged Property, or any part
thereof, to be abandoned, vacated, misused, abused or wasted, or to deteriorate.
Mortgagor shall not, without in each instance the prior consent of Mortgagee,
remove from the Mortgaged Property any fixture, machinery or equipment except
that which is replaced immediately by Mortgagor as part of routine maintenance,
or make any structural or other material alteration to the Mortgaged Property
without in each instance the prior consent of Mortgagee.


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<PAGE>   9

            14. Compliance with Laws. Mortgagor shall comply with all laws,
orders, ordinances, regulations, restrictions and requirements of all
governmental authorities affecting the Mortgaged Property and the use thereof.

            15. No Impairment of Security. Mortgagor shall not do or suffer any
act or forbearance which would impair the security for the Debt or the lien of
this Mortgage on the Mortgaged Property.

            16. No Transfers. Mortgagor shall not assign, convey, mortgage,
pledge, transfer, encumber, grant a security interest with respect to or
hypothecate all or any part of the Mortgaged Property or any interest therein.
Any transfer by operation of law of the Mortgaged Property, or any part thereof
or interest therein, shall constitute a default hereunder. If Mortgagor is a
corporation or partnership, any transfer, sale, pledge or other disposition
(whether in a single transaction or a series of transactions) of 50% or more of
the stock of Mortgagor as of the date hereof (if Mortgagor is a corporation) or
of the partnership interests in Mortgagor as of the date hereof (if Mortgagor is
a partnership) shall constitute a default hereunder.

            17. Notices. All notices, demands, requests, consents, approvals and
other communications hereunder shall be in writing, and shall be mailed United
States registered or certified mail, postage prepaid, or personally delivered,
to the parties at their respective addresses first above noted, or to such other
address as a party may designate by notice to the other party.

            18. Mortgage Tax. If any law or ordinance now or hereafter imposes a
tax (including, without limitation, a document or revenue stamp tax) either
directly or indirectly on this Mortgage, Mortgagor shall pay such tax within the
time same is payable to the relevant taxing authority without penalty.

            19. Entry. Mortgagee, and its agents, employees, contractors and
representatives, shall have the right to enter upon and to inspect the Mortgaged
Property at all times.

            20. Default. The Mortgagor shall be in default hereunder upon the
occurrence of an "Event of Default" as defined in the Note.

            21. Acceleration. The unpaid principal indebtedness of the Note,
plus all other sums secured by this Mortgage and the Security Agreement, and all
accrued interest thereon, shall become due and payable immediately, without
notice or demand upon the occurrence of any default hereunder.

            22. Remedies. Upon the occurrence of any default by Mortgagor
hereunder, Mortgagee may forthwith exercise, separately, concurrently,
successively or otherwise, any


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<PAGE>   10

and all rights and remedies available to Mortgagee pursuant to this Mortgage,
the Note, the Security Agreement or available by law, equity or otherwise,
including without limitation (a) enforcement of payment of the Note, (b)
foreclosure of this Mortgage, (c) institution of action or actions for specific
performance of the agreements and obligations of Mortgagor hereunder, and
Mortgagor agrees that all agreements and obligations of Mortgagor hereunder
shall be specifically enforceable by injunction or any other appropriate
equitable remedy, and (d) with or without taking physical possession of the
Mortgaged Property, the collection and receipt of all income, rents, issues and
profits from the Mortgaged Property, including without limitation the Rents, and
after deducting the costs of alterations, improvements, repairs, operation and
leasing, including without limitation counsel fees, incurred by Mortgagee in
doing any of the foregoing or in taking any of the steps set forth in the
immediately following Section hereof, the application of the net income
therefrom to the Debt in such order and manner as Mortgagee may elect.

            23. Possession. Upon any default by Mortgagor hereunder, and in
addition to all other rights and remedies available to it, Mortgagee shall have
the right, with or without judicial process, to enter upon and take possession
of the Mortgaged Property, breaking open doors and locks if it deems necessary
for such purpose without civil or criminal liability for trespass, damages,
forcible entry and detainer or otherwise, and, upon so doing, Mortgagee may, in
its discretion and in addition to all other rights, as mortgagee in possession,
alter, improve, repair, complete, change or add to the Mortgaged Property or any
part thereof, and, in the name of Mortgagor or Mortgagee (as Mortgagee may
elect), operate and lease the Mortgaged Property or any part thereof upon such
terms and conditions as Mortgagee shall elect. In doing any of the foregoing,
Mortgagee shall have the right to expend such amounts as Mortgagee shall deem
proper, all of which expenditures, with interest thereon from the dates of such
expenditures until repaid at the Default Rate specified in the Note, shall be
payable on demand of Mortgagee.

            24. Action for Possession. The provisions of this Section shall
apply whenever and as often as Mortgagee shall have the right to take possession
of the Mortgaged Property. Mortgagor irrevocably appoints, authorizes and
empowers any attorney of any court of competent jurisdiction to appear as
attorney, and, in addition, as attorney-in-fact (which appointment shall be
deemed coupled with an interest), for Mortgagor, as well as for all persons
claiming under, by or through Mortgagor, to sign an agreement for entering in
any such court an amicable action in ejectment for possession of the Mortgaged
Property, without the necessity of filing any bond and without any stay of
execution or appeal, against Mortgagor and all persons claiming under, by or
through Mortgagor, and/or, as Mortgagee may elect, confess judgment in ejectment
for the recovery by Mortgagee of possession of the Mortgaged Property. For all
such action this instrument, or a copy thereof verified by affidavit of
Mortgagee or anyone on behalf of Mortgagee, shall be a sufficient warrant. Upon
entry of such agreement or judgment, a writ of possession or other appropriate
process to obtain possession of the Mortgaged Property may be issued forthwith,
without any prior writ or proceeding whatsoever, Mortgagor hereby releasing and
agreeing to release Mortgagee and


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<PAGE>   11

said attorneys from all errors and defects whatsoever in entering such agreement
or judgment or in causing such writ or process to be issued or in any proceeding
thereon or concerning the same, provided that Mortgagee shall have filed in such
action an affidavit made by someone on Mortgagee's behalf setting forth the
facts necessary to authorize the entry of such agreement or judgment according
to the terms of this Mortgage, of which facts such affidavit shall be conclusive
evidence. If for any reason after any such action has been commenced, the same
shall be discontinued, marked satisfied of record or be terminated, or
possession of the Mortgaged Property remain in or be restored to Mortgagor or
anyone claiming under, by or through Mortgagor, Mortgagee may, whenever and as
often as Mortgagee shall have the right to take possession again of the
Mortgaged Property, bring one or more further amicable actions in the manner
herein before set forth to recover possession of the Mortgaged Property and to
enter one or more confessed judgments as hereinabove provided, and the authority
and power above given to any such attorney shall extend to all such further
amicable actions and judgments. Mortgagee shall have the right to bring such
amicable action in ejectment and confess judgment therein as hereinabove
provided whether before or after an action of mortgage foreclosure is brought or
foreclosure or other proceedings are instituted or concluded upon this Mortgage
or the Note.

            25. Appointment of Receiver. Upon any default by Mortgagor,
Mortgagee, as a matter of right and without notice, and without regard to the
then value of the Mortgaged Property or the interest of Mortgagor therein, shall
have the right to apply to any court having jurisdiction to appoint a receiver
or sequestrator of the Mortgaged Property, and the Mortgagor hereby irrevocably
consents to such appointment and waives notice of any application therefor.

            26. Sale. If this Mortgage is foreclosed, or if judgment is entered
against Mortgagor under the Note, the Mortgaged Property may, at the discretion
of Mortgagee, be sold as a whole or in parts or lots, or in several interests or
portions and in any order or manner.

            27. Attorneys' Fees. In the event Mortgagee consults attorneys for
the collection of any of the Debt or the enforcement of any of the terms,
covenants or conditions hereof or of the Note, Mortgagor shall pay on demand all
fees, costs and expenses of such attorneys.

            28. Mortgagee's Right to Perform Obligations. If Mortgagor shall
default in the performance of any of its agreements or obligations hereunder or
under the Note or the Base Lease, then Mortgagee shall have the right, but not
the obligation, to perform same for Mortgagor and to make all advances of funds
in connection therewith as Mortgagee deems appropriate, in which case all costs
and expenses so incurred by Mortgagor (including without limitation attorneys'
fees) shall be paid by Mortgagor on demand, together with interest at the
Default Rate from the date of incurrence until the date of payment. If Mortgagee
shall elect to perform any such agreement or obligation, then Mortgagee shall be
subrogated to all the rights


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<PAGE>   12

and remedies of all other persons intended to be or in fact benefited by the
performance of such agreement or obligation. No such performance by Mortgagee
shall be deemed to relieve Mortgagor from any default hereunder or impair any
right or remedy consequent thereon and the exercise of the right of performance
granted in this Section shall be optional with Mortgagee and not obligatory, and
Mortgagee shall not in any case be liable to Mortgagor for a failure or refusal
(a) to exercise any such right, or (b) to continue to exercise such right after
having commenced such exercise.

            29. Waivers. Mortgagor hereby waives and relinquishes the benefits
of any present or future laws: (a) exempting the Mortgaged Property, or any part
thereof, or any other property whatsoever, or of the proceeds arising from any
sale thereof, from attachment, levy, sale or execution, (b) staying of execution
or other process, or (c) requiring valuation or appraisement of the Mortgaged
Property or of any other property levied or sold in execution on any judgment
for the Debt. Mortgagor, so far as permitted by law, waives and will waive the
right to a trial by jury in connection with all suits, actions or proceedings
instituted by the Mortgagee.

            30. Cumulative Remedies. All rights and remedies of Mortgagee
hereunder and under the Note and any other security now or hereafter given with
respect to the Debt are separate, distinct and cumulative and in addition to the
rights and remedies provided by law. The failure of Mortgagee to insist upon
strict performance of any term or provision hereof shall not be deemed to be a
waiver of such term or provision, or of any right or remedy of Mortgagee.

            31. Further Assurances. Mortgagor shall, promptly following the
request of Mortgagee, execute, acknowledge, deliver and record or file such
further documents and do such further acts as Mortgagee may deem necessary,
desirable or proper to carry out more effectively the purposes of this Mortgage
or to protect the lien or the security interest granted herein against the
rights or interests of third persons, and Mortgagor shall pay on demand all
costs connected with any of the foregoing.

            32. Estoppel Certificates. Mortgagor, within five days following the
request of Mortgagee from time to time, shall furnish a duly acknowledged
written statement to Mortgagee and to any other person designated by Mortgagee,
setting forth the amount of the Debt secured by this Mortgage and stating either
that no offset or defense exists against the Debt, or if any such offset or
defense is alleged to exist, stating the nature and amount thereof.

            33. Invalidity. If any term, provision, or condition of this
Mortgage, the Note or any other security now or hereafter given with respect to
the Debt, or the application thereof to any person or circumstance, shall be
invalid, illegal or unenforceable in any respect, the remainder of this
Mortgage, the Note and such other security shall be construed without such
provision and the application of such term or provision to persons or
circumstances other than those as to which it is held invalid, illegal or
unenforceable, as the case may be, shall not


                                       11
<PAGE>   13

be affected thereby, and each term and provision of this Mortgage, the Note and
such other security shall be valid and enforced to the fullest extent permitted
by law.

            34. Headings; Pronouns. The headings of the sections of this
Mortgage are for convenience only and have no meaning with respect to this
Mortgage or the rights or obligations of Mortgagor or Mortgagee. Unless the
context clearly indicates a contrary intent or unless otherwise specifically
provided herein: words used in this Mortgage are used interchangeably in
singular or plural form; "person", as used herein, includes an individual,
corporation, partnership, trust, unincorporated association, government,
governmental authority, or other entity; "Mortgaged Property" includes all and
singular each and every portion of the Mortgaged Property and estate or interest
therein; "holder" means any holder from time to time of the Note; "hereof",
"herein" and "hereunder" and other words of similar import refer to this
Mortgage as a whole; "Mortgage" includes these presents as supplemented or
amended from time to time by written instrument(s) entered into by Mortgagor and
Mortgagee; "Note" includes all written supplements or amendments to the Note
from time to time entered into by Mortgagor and Mortgagee; "Mortgagor" includes
Mortgagor's trustees, successors and permitted assigns; and "Mortgagee" includes
Mortgagee's trustees, successors and assigns. Whenever the context may require,
all pronouns used herein shall include the corresponding masculine, feminine or
neuter forms, and the singular form of pronouns or nouns shall include the
plural and vice versa.

            35. Amendments. This Mortgage can be changed only by a written
instrument executed by Mortgagor and Mortgagee.

            36. Governing Law. This Mortgage and all issues arising hereunder
shall be governed by the laws of the state in which the Real Estate is located.

            37. Counterparts. This Mortgage may be executed in any number of
counterparts, each of which shall constitute an original instrument.

             IN WITNESS WHEREOF, Mortgagor has executed this Mortgage as of the
date first above written.

(CORPORATE SEAL)                        BIOPURE CORPORATION, as Mortgagor

Attest:
                                        By: /s/ Brian A. Lajoie
/s/ Maria S. Gawryl                         ------------------------------------
-------------------------                   Name: Brian A. Lajoie
Name: Maria S. Gawryl                       Title: V.P. - Finance
Title: V.P.-R&D


                                        PHARMACIA & UPJOHN, INC., as
                                         Mortgagee

                                        By: /s/ Robert G. Kramer
                                            ------------------------------------
                                            Name: Robert G. Kramer
                                            Title: Director Corporate Treasury


                                       12
<PAGE>   14

STATE OF       :
               : SS
COUNTY OF      :

            On this, the 7th day of October, 1996, before me, a notary public,
the undersigned officer, personally appeared Brian A. Lajoie, who acknowledged
himself to be the VP-Finance of Biopure Corporation, a Delaware corporation, and
that he as such officer, being authorized to do so, executed the foregoing
instrument for the purposes therein contained by signing the name of the
corporation by himself as such officer.

            In witness whereof, I hereunto set my hand and official seal.

                                (Notarial Seal)


                                        /s/ Hazel V. Forney
                                        ----------------------------------------
                                        Notary Public
                                        My Commission Expires: Jan 4, 2002


STATE OF       :
               : SS
COUNTY OF      :

            On this, the ________ day of _______________, 1996, before me, a
notary public, the undersigned officer, personally appeared __________________,
who acknowledged himself to be the ___________________ of Pharmacia & Upjohn,
Inc., a Delaware corporation, and that he as such officer, being authorized to
do so, executed the foregoing instrument for the purposes therein contained by
signing the name of the corporation by himself as such officer.

            In witness whereof, I hereunto set my hand and official seal.

                                (Notarial Seal)



                                        ----------------------------------------
                                        Notary Public
                                        My Commission Expires:

<PAGE>   15

STATE OF       :
               : SS
COUNTY OF      :

            On this, the ________ day of _______________, 1996, before me, a
notary public, the undersigned officer, personally appeared __________________,
who acknowledged himself to be the ___________________ of Biopure Corporation, a
Delaware corporation, and that he as such officer, being authorized to do so,
executed the foregoing instrument for the purposes therein contained by signing
the name of the corporation by himself as such officer.

            In witness whereof, I hereunto set my hand and official seal.

                                (Notarial Seal)



                                        ----------------------------------------
                                        Notary Public
                                        My Commission Expires:


STATE OF Michigan    :
                     : SS
COUNTY OF Kalamazoo  :

            On this, the 7th day of October, 1996, before me, a notary public,
the undersigned officer, personally appeared Robert G. Kramer, who acknowledged
himself to be the Director Corporate Treasury of Pharmacia & Upjohn, Inc., a
Delaware corporation, and that he as such officer, being authorized to do so,
executed the foregoing instrument for the purposes therein contained by signing
the name of the corporation by himself as such officer.

            In witness whereof, I hereunto set my hand and official seal.

                                (Notarial Seal)


                                        /s/ Carolyn S. Vandermolen
                                        ----------------------------------------
                                        Notary Public
                                        My Commission Expires:

                                        17 January 2001

<PAGE>   16

                                   Exhibit "A"

                             DESCRIPTION OF THE LAND

                                  See Attached
<PAGE>   17

                                    EXHIBIT A

      Spring Street Land:

      Certain parcels of land with the building thereon, situated in Cambridge,
Middlesex County, Massachusetts, bounded and described as follows:

Parcel I

      Beginning at a point on the southerly side of Spring Street, distant one
hundred (100) feet easterly from Second Street, thence turning and running

      EASTERLY:   bounded northerly, by Spring Street, sixty (60) feet;
                  thence turning at right angles and running

      SOUTHERLY:  bounded easterly, by land now or late of Franklin Wilkins,
                  one hundred (100) feet; thence turning and running

      WESTERLY:   bounded southerly, by land now or late of Simonds, sixty
                  (60) feet; and thence turning and running

      NORTHERLY:  bounded westerly, by land now or late of John P. Squire,
                  one hundred (100) feet to the point of beginning.

      Containing 6000 square feet of land.

      Said premises are commonly known as and numbered 16-18 Spring Street.

Parcel II

      The land situated on Spring Street, shown as Lot B on Plan of Lands
belonging to John P. Squire Est., East Cambridge, Mass. Dec. 1909 by James
Adams C.E. recorded in Middlesex Plan Book 182, Page 40, bounded:

      NORTHERLY:  by Spring Street seventy-three and 60/100 (73.60) feet:

      EASTERLY:   by land now or formerly of Sousa one hundred one and
                  52/100 (101.52) feet;

      SOUTHERLY:  by Lot C on said plan fifty (50) feet;

      WESTERLY:   by Lot C on land now or late of McCarthy as shown on said
                  plan thirty-seven and 75/100 (37.75) feet;

                                                                     (continued)
<PAGE>   18

                               EXHIBIT A (cont.)


      Spring Street Land (cont.)

      SOUTHERLY:  again by land now or late of McCarthy twenty-three and
                  50/100 (23.50) feet;

      WESTERLY:   again by Lot A on said plan sixty-three and 85/100
                  (63.85) feet.

      Containing six thousand five hundred seventy-nine (6,579) square feet
according to said plan.

      Said premises are commonly known as and numbered 20-22 Spring Street.

Parcel III

A certain parcel of land together with the buildings thereon situated at 26
Spring Street, Cambridge, Middlesex County, Massachusetts and being shown as Lot
"A" on a plan entitled "Plan of Land belonging to John P. Squire Estate, East
Cambridge, Massachusetts", dated December 1909, drawn by James Adam, C.E., and
duly recorded with Middlesex South District Deeds in Plan Book 182, Plan 40 and
being further bounded and described as follows:

      NORTHERLY   by Spring Street twenty-six and 50/100 (26.50) feet;

      WESTERLY    by Second Street sixty-three and 85/100 (63.85) feet;

      SOUTHERLY   by land now or formerly of Charles J. McCarthy twenty-six
                  and 50/100 (26.50) feet; and

      EASTERLY    by Lot B as shown on said plan sixty-three and 85/100 (63.85)
                  feet.

      Containing 1692 square feet of land, more or less.

                                                                     (continued)
<PAGE>   19

                               EXHIBIT A (cont.)


37-39 Hurley Street Land:

      Parcel One        A certain parcel of land being at present numbered
                        90-96 inclusive, Second Street, Cambridge, being shown
                        as Lots A and B on a plan entitled "Subdivision Plan of
                        Land in Cambridge, Mass.," dated September 7, 1946 by
                        Ray L. Coolidge, Eng., recorded with Middlesex South
                        District Deeds in Book 7062, Page 243, together bounded
                        and described as follows:

                        WESTERLY    by Second Street, one hundred six and
                                    83/100 (106.83) feet;

                        NORTHERLY   by land of owners unknown (formerly of
                                    Charles J. McCarthy), forty-five (45)
                                    feet;

                        EASTERLY    By Lot C on said plan, one hundred six
                                    and 79/100 (106.79) feet;

                        SOUTHERLY   by Hurley Street, forty-five (45) feet.

                        Containing according to said plan 4806 square feet of
                        land be all measurements more or less or however
                        otherwise bounded or described. Said premises constitute
                        the greater portion of Lots 1 and 2 on a plan recorded
                        with said deeds at the end of record book 4996.

      Parcel Two        A certain parcel of land with the buildings thereon
                        situated on Hurley Street, Cambridge, Middlesex
                        County, and being shown as Lot C on said Plan
                        entitled "Subdivision Plan of Land in Cambridge,
                        Mass.," dated September 7, 1946 by Ray L. Coolidge,
                        Eng., recorded with Middlesex South District Deeds
                        in Book 7062, Page 243, bounded and described as
                        follows:

                        SOUTHERLY   by said Hurley Street, 55 feet;

                        WESTERLY    by Lot A and by Lot B as shown on said plan,
                                    one hundred six and 79/100 (106.79) feet;

                        NORTHERLY   by land now or formerly of owners
                                    unknown, five (5) feet;

                                                                     (continued)
<PAGE>   20

                               EXHIBIT A (cont.)


37-39 Hurley Street Land (cont.)

                        NORTH-
                        EASTERLY    by land now or formerly of owners
                                    unknown, seven and 75/100 (7.75) feet,
                                    more or less;

                        NORTHERLY   by land now or formerly of owners
                                    unknown, fifty (50) feet; and

                        EASTERLY    by land now or formerly of owners unknown,
                                    ninety-nine (99) feet.

                        Containing 5485 square feet of land more or less as
                        shown on said plan.

                                                                     (continued)
<PAGE>   21

                               EXHIBIT A (cont.)


31-35 Hurley Street Land:

      A certain parcel of land with the buildings thereon, shown as Lot C on a
Plan of Land in Cambridge, M. Walters, C.E., dated August 8, 1941, and recorded
with the Middlesex South District Registry of Deeds in Book 6546, Page 207, and
bounded and described as follows:

      SOUTHWESTERLY:    by Hurley Street, sixty (60) feet;

      NORTHWESTERLY:    by land of owners unknown, one hundred (100) feet;

      NORTHEASTERLY:    by land of owners unknown, sixty (60) feet;

      SOUTHEASTERLY:    by Lot B on said plan, one hundred (100)
                        feet.

      Containing 6,000 square feet of land according to said plan.

<PAGE>   22

                                CONSENT OF LESSOR

      Tarvis Realty Trust, being the lessor with respect to that certain
leasehold agreements dated October 12, 1990, August 23, 1994, May 10, 1994
respectively, and concerning the properties known and numbered as 22 Spring
Street, 37-39 Hurley Street, 31-35 Hurley Street respectively, Cambridge,
Massachusetts, hereby consents to the grant of a security interest in and to
said leasehold agreements by the lessee thereof, Biopure Corporation, to
Pharmacia & Upjohn, Inc. to secure payments of principal and interest on a
promissory note in the amount of $9,000,000.00 and certain other sums, subject
to each of the terms, covenants and conditions set forth in said leasehold
agreements. To the extent that there may be any inconsistency between the terms,
covenants and conditions of said leasehold agreements and the provisions of any
and all security agreements that may be executed by the lessee, the terms,
covenants and conditions of said leasehold agreements shall control. The lessor
also acknowledges that said leasehold agreements is in effect and that there are
no defaults of the lessee existing thereunder.

      Executed as an instrument under seal this 7th day of October, 1996


                                          Tarvis Realty Trust, Lessor


                                          /s/ Varney J. Hintlian
                                          --------------------------------
                                          TRUSTEE

Source: OneCLE Business Contracts.