<Page>

Ex. 4.7
Form of Mortgage Note

                                   Exhibit 4.7
                  Form of Mortgage Note between the Company and
             Allstate Life Insurance Company dated December 14, 2001

The following is the form of the Mortgage Note used in two transactions dated
December 14, 2001 between the Company and Allstate Life Insurance Company. In
the first transaction, Allstate provided a mortgage loan totaling $16,750,000 to
GLR Corporate Center LLC, a subsidiary of the Company, encumbering the Company's
property located at 1600 Golf Road, Rolling Meadows, Illinois. In the second
transaction Allstate provided a mortgage loan totaling $6,250,000 to Great Lakes
REIT, L.P. encumbering the Company's property located at 1920-1930 Thoreau
Drive, Schaumburg, Illinois.

Allstate Life Insurance Company
Loan No.________

MORTGAGE NOTE

$                                               December 14, 2001

1.    PAYMENT OF PRINCIPAL AND INTEREST FOR VALUE RECEIVED, GLR - 1600 CORPORATE
CENTER, LLC, a Delaware limited liability company ("Maker") hereby promises to
pay to the order of ALLSTATE LIFE INSURANCE COMPANY, and any subsequent holder
of this Note ("Holder" or "Holders") in the manner hereinafter provided, the
principal amount of SIXTEEN MILLION SEVEN HUNDRED FIFTY THOUSAND DOLLARS
($16,750,000) together with interest on the outstanding principal balance from
the date of the initial disbursement (for purposes of this Note, "disbursement"
means the date funds are wire transferred from Holder's account) of all or a
part of the principal of this Note ("Disbursement Date") until maturity at the
rate of six and sixtyfive one hundredths percent (6.65%) per annum ("Contract
Rate") as follows:

      (a)  on the Disbursement Date, interest only, in advance, accruing from
the Disbursement Date to the last day of December, 2001, both inclusive; and

      (b)  in arrears, on the first day of February, 2002 and on the first day
of each month thereafter until this Note matures, principal and interest in
consecutive equal installments of ONE HUNDRED TWENTY SIX THOUSAND THREE HUNDRED
SIXTY SEVEN AND 07/100 DOLLARS ($126,367.07) (the initial payment and each
subsequent payment shall each hereinafter be referred to as "Monthly Payment"),
which amount is calculated using an amortization period of two hundred forty
(240) months; and

      (c)  on January 1, 2007, the entire unpaid principal amount and any
interest accrued but remaining unpaid and all other sums due under this Note.

Except for the interest payable under paragraph (a) above, interest shall be
payable in arrears and calculated on the basis of a 360 day year containing
twelve 30 day months. All such payments on account of the indebtedness evidenced
by this Note shall be first applied to interest accrued on the unpaid principal
amount and the remainder toward reduction of the unpaid principal amount.

2.    PAYMENT INFORMATION All payments required to be made hereunder shall be
made during regular business hours to Holder at its office c/o Commercial
Mortgage Division, Allstate Plaza South, Suite G5C, 3075 Sanders Road,
Northbrook, Illinois 60062, Attention: Servicing Manager, with sufficient
information to identify the source and application of such payment to Holder's
Loan #122081, or at such other place as Holder may from time to time designate
in writing. All payments shall be made in currency of the United States of
America without presentment or surrender of this Note. Payments to Holder shall
be made by transferring immediately available federal funds by

                                       54
<Page>

bank wire or interbank transfer for the account of Holder. Any payment of
principal or interest received after 1:00 p.m., Chicago time, shall be deemed to
have been received by Holder on the next business day and shall bear interest
accordingly. If and so long as Holder directs Maker to make payments to a
servicing agent, then payments may be made by check. Payments made by check will
not be deemed made until good funds for such check are received by Holder or the
servicing agent.

3.    SECURITY FOR NOTE The payment of this Note and all other sums due Holder
is secured by a Mortgage, Assignment of Leases, Rents and Contracts, Security
Agreement and Fixture Filing ("Mortgage"), of even date herewith, granted by
Maker to Holder, as mortgagee, covering certain real property, the improvements
thereon and certain personal property situated in the County of Cook, State of
Illinois and described in the Mortgage ("Property"), and those certain
instruments of indebtedness and security described as "Related Agreements" in
the Mortgage. Except as otherwise defined herein, all of the defined terms
contained in the Mortgage and the Related Agreements are hereby incorporated
herein by express reference.

4.    LATE CHARGES If any Monthly Payment required under this Note is not paid
in full on or before the fifth day of the month in which such payment is due,
Maker acknowledges that the Holder will incur extra expenses for the handling of
the delinquent payment and servicing the indebtedness evidenced hereby, and that
the exact amount of these extra expenses is extremely difficult and impractical
to ascertain, but that a charge of four percent (4%) of the amount of the
delinquent payment ("Late Charge") would be a fair approximation of the expense
so incurred by Holder. If applicable law requires a lesser charge, however, then
the maximum charge permitted by such law may be charged by Holder for said
purpose. Therefore, Maker shall, in such event, without further notice, and
without prejudice to the right of Holder to collect any other amounts provided
to be paid hereunder or under the Mortgage, the Related Agreements or any other
instrument executed for purposes of further securing payment of the obligations
evidenced by this Note, or to declare an Event of Default as defined below, pay
to Holder immediately upon demand the Late Charge to compensate Holder for
expenses incurred in handling delinquent payments.

5.    INTEREST PAYABLE UPON DEFAULT If there occurs an Event of Default, under
this Note or the Mortgage or under any Related Agreement, then the unpaid
principal amount of this Note, and all accrued and unpaid interest thereon shall
bear interest at the Contract Rate plus four percent (4%) per annum compounded
monthly ("Default Rate") from the date of expiration of any applicable cure or
grace period until such time, if any, as the Event of Default is cured and the
Mortgage and this Note are reinstated as permitted by applicable law, or
otherwise until such time as the unpaid principal amount of this Note and all
other indebtedness evidenced by this Note are fully repaid, whichever is
earlier.

6.    EVENTS OF DEFAULT An "Event of Default" shall exist under this Note:

      (a)  in the event Maker shall fail to make any payment due under this
Note, other than the final payment and Prepayment Premium, on or before the
sixth day of the month in which such payment is due;

      (b)  in the event Maker shall fail to make the final payment or the
Prepayment Premium when such payment is due; or,

      (c)  if there shall exist an Event of Default under the Mortgage or any of
the Related Agreements.

7.    ADDITIONAL PAYMENTS The additional payments called for under Paragraphs 4
and 5 shall be in addition to, and shall in no way limit, any other rights and
remedies provided for in this Note, the Mortgage, any Related Agreements, or
otherwise provided by law.

8.    PAYMENT OF TAXES AND EXPENSES

      (a)  Maker further promises to pay to Holder, immediately upon written
notice from Holder: (i) all recordation, transfer, stamp, documentary or other
fees or taxes levied on Holder (exclusive of Holder's income taxes) by reason of
the making or recording of this Note, the Mortgage or any of the Related
Agreements, and (ii) all intangible property taxes levied upon any Holder of
this Note or mortgagee under the Mortgage or secured party under the Related
Agreements.

                                       55
<Page>

      (b)  Maker further promises to pay to Holder, immediately upon written
notice from Holder, all actual costs, expenses, disbursements, escrow fees,
title charges and reasonable legal fees and expenses incurred by Holder and its
counsel in connection with: (i) the collection, attempted collection, or
negotiation and documentation of any settlement or workout of any payment due
hereunder, and (ii) any suit or proceeding whatsoever in regard to this Note or
the protection or enforcement of the lien of any instrument securing this Note,
including, without limitation, in any bankruptcy proceeding or judicial or
nonjudicial foreclosure proceeding. It is the intent of the parties that Maker
pay all expenses and reasonable attorneys' fees incurred by Holder as a result
of Holder's entering into the loan transaction evidenced by this Note.

9.    PREPAYMENT Maker is prohibited from prepaying this Note until January 1,
2003 (the "No-Prepayment Period"). Subsequent to the No-Prepayment Period, at
any time with not less than thirty (30) days prior written notice to Holder,
specifying the date of prepayment, Maker will have the privilege of prepaying
the outstanding principal amount together with any accrued but unpaid interest,
any other sums secured by the Mortgage and the Related Agreements, and a
prepayment premium ("Prepayment Premium") equal to the greater of:

      (a)  1% of the principal amount prepaid, or

      (b)  the yield maintenance payment calculated as follows:

           If the Prevailing Interest Rate is less than the Contract Rate, the
           yield maintenance payment shall be the remainder of (x) minus (y)
           where "(x)" is the present value of all unpaid installments of
           principal and interest due under this Note from the date of
           prepayment to and including the original maturity date of this Note,
           discounted at the Prevailing Interest Rate, and "(y)" is the
           outstanding principal balance of this Note as of the prepayment date.
           The term "Prevailing Interest Rate" as used herein shall mean the
           yield to maturity on a United States Treasury Bond or Treasury Note
           selected by Holder having a maturity date as near as possible to the
           original maturity date of this Note and an "ask" price, as close as
           possible to par (as published two weeks prior to the specified date
           of prepayment in THE WALL STREET JOURNAL or similar publication or
           available from the Federal Reserve Bank of New York), less the Basis
           Point Adjustment as computed in accordance with EXHIBIT A attached
           hereto to convert the monthly payments to a semi-annual equivalent.

      No Prepayment Premium shall be due on the principal balance prepaid within
the thirty (30) day period prior to the original maturity date of this Note.
Written notice of Maker's election to make a prepayment in full of this Note
shall be given in the manner provided for notices under the Mortgage. Partial
prepayment of the outstanding principal amount of this Note shall not be
permitted except in accordance with the terms of the Mortgage. In the event of
such a permitted partial prepayment, the Prepayment Premium calculated in this
paragraph 9 shall be prorated based on the amount of the partial prepayment
relative to the then current outstanding principal balance of this Note.

      Maker acknowledges that Holder:

      (a)  has advanced the amounts evidenced by this Note with the expectation
that such amounts would be outstanding for a period at least equal to the
No-Prepayment Period;

      (b)  would not have been willing to advance such amounts on these terms
for a shorter period of time;

      (c)  in making the loan evidenced by this Note, is relying on Maker's
creditworthiness and its agreement to pay in strict accordance with the terms
set forth in the Note; and

      (d)  would not make the loan without full and complete assurance by Maker
of its agreement not to prepay all or a part of the principal of this Note
except as expressly permitted herein and in the Mortgage. Maker has been advised
and acknowledges that Holder is relying on the receipt of payments under this
Note to, among other things, match and support its obligations under contracts
entered into by Holder with third parties and that in the event of a prepayment,
Holder could suffer loss and additional expenses which are extremely difficult
and

                                       56
<Page>

impractical to ascertain. Accordingly, it is the express intent of Maker and
Holder that (i) Maker shall have no right to prepay this Note during the
No-Prepayment Period, (ii) any prepayment of this Note during the No-Prepayment
Period shall only occur in the event Holder accelerates payment under this Note
or as otherwise set forth in the Mortgage, (iii) any prepayment described in the
foregoing clause (ii) shall (unless otherwise expressly permitted in the
Mortgage) require the payment of a Prepayment Premium calculated as provided for
hereinabove; and (iv) to the extent permitted by applicable law, Maker has
waived, and hereby waives, any right to prepay this Note except as expressly
provided in the Mortgage or this Note. In the event, notwithstanding the
foregoing express intent of Maker and Holder and the express waiver by Maker of
any right to prepay this Note, that the applicable law of the jurisdiction in
which the Property is located permits the Maker to prepay this Note during the
No-Prepayment Period, then the Prepayment Premium described in clause (iii)
above shall be paid to Holder as a condition to any such prepayment.

      Maker expressly acknowledges that, pursuant to the provisions of this Note
and except as otherwise provided in this Note or the Mortgage, Maker has no
right to prepay this Note in whole or in part. In the event any prepayment is
required or expressly permitted, Maker shall be liable for the payment of the
Prepayment Premium unless expressly stated otherwise in the Mortgage.
Furthermore, Maker waives any rights it may have under any applicable state laws
as they relate to any prepayment restrictions contained in this paragraph 9 or
otherwise contained in this Note and expressly acknowledges that Holder has made
the loan in reliance upon such agreements and waiver of Maker and that Holder
would not have made the loan without such agreements and waiver of Maker. Maker
acknowledges that specific weight has been given to the consideration given for
such agreements, which consideration is the granting of the loan.

10.   EVASION OF PREPAYMENT PREMIUM Except as expressly provided in the
Mortgage, Maker acknowledges that in the event of an acceleration of payment of
this Note following an Event of Default by Maker, a tender of payment of an
amount necessary to satisfy the entire indebtedness evidenced hereby, but not
including the Prepayment Premium, made at any time prior to a foreclosure sale
by Maker, its successors or assigns or by anyone on behalf of Maker, shall be
presumed to be and conclusively deemed to constitute a deliberate evasion of the
prepayment provisions hereof and shall constitute a prepayment hereunder and
shall therefore be subject to the Prepayment Premium as calculated in accordance
with this Note with the date of prepayment being deemed the date of occurrence
of the foreclosure sale or the tender of payment of the amount necessary to pay
the entire indebtedness evidenced hereby in full, including the Prepayment
Premium.

11.   MAKER'S COVENANTS Maker agrees that:

      (a)  this instrument and the rights and obligations of all parties
hereunder shall be governed by and construed under the laws of the state or
commonwealth in which the Property is located;

      (b)  the obligation evidenced by this Note is an exempted transaction
under the Truth-in-Lending Act, 15 U.S.C Section 1601, ET SEQ.(1982);

      (c)  said obligation constitutes a business loan for the purpose of the
application of any laws that distinguish between consumer loans and business
loans and that have as their purpose the protection of consumers in the state or
commonwealth in which the Property is located;

      (d)  at the option of the Holder, the United States District Court for the
district in which the Property is located and any court of competent
jurisdiction of the state or commonwealth in which the Property is located shall
have jurisdiction in any action, suit or other proceeding arising out of or
relating to any act taken or omitted hereunder or the enforcement of this Note,
the Mortgage and the Related Agreements and Maker shall not assert in any such
action, suit or other proceeding that it is not personally subject to the
jurisdiction of such courts, that the action, suit or other proceeding is
brought in an inconvenient forum or that the venue of the action, suit or other
proceeding is improper;

      (e)  it hereby waives any objections to venue; and

      (f)  it hereby waives its right to a trial by jury.

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12.   SEVERABILITY The parties hereto intend and believe that each provision of
this Note comports with all applicable local, state and federal laws and
judicial decisions. However, if any provision or any portion of any provision
contained in this Note is held by a court of law to be invalid, illegal,
unlawful, void or unenforceable as written in any respect, then it is the intent
of all parties hereto that such portion or provision shall be given force to the
fullest possible extent that it is legal, valid and enforceable, that the
remainder of the Note shall be construed as if such illegal, invalid, unlawful,
void or unenforceable portion or provision was not contained therein, and the
rights, obligations and interests of Maker and Holder under the remainder of
this Note shall continue in full force and effect.

13.   USURY LAWS It is the intention of Maker and Holder to conform strictly to
the usury laws now or hereafter in force in the state or commonwealth in which
the Property is located, and any interest payable under this Note, the Mortgage,
or any Related Agreement shall be subject to reduction to an amount not to
exceed the maximum non-usurious amount for commercial loans allowed under the
usury laws of the state or commonwealth in which the Property is located as now
or hereafter construed by the courts having jurisdiction over such matters. In
the event such interest (whether designated as interest, service charges,
points, or otherwise) does exceed the maximum legal rate, it shall be

      (a)  canceled automatically to the extent that such interest exceeds the
maximum legal rate;

      (b)  if already paid, at the option of the Holder, either be rebated to
Maker or credited on the principal amount of the Note; or

      (c)  if the Note has been prepaid in full, then such excess shall be
rebated to Maker.

14.   ACCELERATION Upon the occurrence of an Event of Default, Holder shall have
the right, without demand or notice, to declare the entire principal amount of
this Note and/or any Future Advance (as defined in the Mortgage) then
outstanding, all accrued and unpaid interest thereon and all other sums payable
under this Note, which shall include the Prepayment Premium (calculated as
provided for in Paragraph 9 hereinabove), the Mortgage or any note evidencing
any Future Advance, to be immediately due and payable and, notwithstanding the
stated maturity in this Note or any note evidencing any Future Advance, all such
sums declared due and payable shall thereupon become immediately due and
payable. During the existence of such Event of Default, Holder may apply
payments received on any amounts due under this Note, the Mortgage, any Related
Agreement or any note evidencing any Future Advance as Holder may determine in
its sole discretion.

15.   WAIVERS BY MAKER As to this Note, the Mortgage, the Related Agreements and
any other instruments securing the indebtedness, Maker and all guarantors,
sureties and endorsers, severally waive all applicable exemption rights, whether
under any state constitution, homestead laws or otherwise, and also severally
waive diligence, valuation and appraisement, presentment for payment, protest
and demand, notice of protest, demand and dishonor and diligence in collection
and nonpayment of this Note and all other notices in connection with the
delivery, acceptance, performance, default, or enforcement of the payment of
this Note (except notice of default specifically provided for in the Mortgage
and the Related Agreements). To the extent permitted by law, Maker further
waives all benefit that might accrue to Maker by virtue of any present or future
laws exempting the Property, or any other property, real or personal, or the
proceeds arising from any sale of any such property, from attachment, levy, or
sale under execution, or providing for any stay of execution to be issued on any
judgment recovered on this Note or in any action to foreclose the Mortgage,
injunction against sale pursuant to power of sale, exemption from civil process
or extension of time for payment. Maker agrees that any real estate that may be
levied upon pursuant to a judgment obtained by virtue of this Note, or any writ
of execution issued thereon, may be sold upon any such writ in whole or in part
in any order desired by Holder.

16.   MAKER NOT RELEASED No delay or omission of Holder to exercise any of its
rights and remedies under this Note, the Mortgage or any Related Agreements at
any time following the happening of an Event of Default shall constitute a
waiver of the right of Holder to exercise such rights and remedies at a later
time by reason of such Event of Default or by reason of any subsequently
occurring Event of Default. This Note, or any payment hereunder, may be extended
from time to time by agreement in writing between Maker and Holder without in
any other way affecting the liability and obligations of Maker and endorsers, if
any.

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17.   NONRECOURSE Except as otherwise set forth in this section, Holder's
recourse under this Note, the Mortgage and the Related Agreements shall be
limited to and satisfied from the Property and the proceeds thereof, the rents
and all other income arising therefrom, the other assets of Maker arising out of
the Property which are given as collateral for this Note, and any other
collateral given in writing to Holder as security for repayment of this Note
(all of the foregoing are collectively referred to as the "Loan Collateral").
Notwithstanding the preceding sentence:

      (a)  Holder may, in accordance with the terms of this Note, the Mortgage
or any Related Agreement: (i) foreclose the lien of the Mortgage, (ii) take
appropriate action to enforce this Note, the Mortgage and any Related Agreements
to realize upon and/or protect the Loan Collateral, (iii) name Maker as a party
defendant in any action brought under this Note, the Mortgage or any Related
Agreement so long as the exercise of any remedy is limited to the Loan
Collateral, (iv) pursue all of its rights and remedies against any guarantor or
surety or master tenant, whether or not such guarantor or surety or master
tenant is a partner, member or other owner of Maker, (v) pursue all of its
rights and remedies against Maker and the indemnitors under that certain
Environmental Indemnity Agreement of even date herewith or (vi) pursue all of
its rights and remedies under that certain Payment Guaranty of even date
herewith made by Great Lakes REIT, a Maryland real estate investment trust
("Guarantor") in favor of Holder;

      (b)  Holder may seek damages or other monetary relief or any other remedy
at law or in equity against Maker, any general partner of Maker and the
Guarantor under that certain Nonrecourse Carveout Guaranty of even date herewith
("Nonrecourse Guaranty") by reason of or in connection with (i) the failure of
Maker to pay to Holder, upon demand, all rents, issues and profits of the
Property to which Holder is entitled pursuant to this Note, the Mortgage or the
Related Agreements following an Event of Default, (ii) any waste of the Property
or any willful act or omission by Maker which damages or materially reduces the
value of the Property, (iii) the failure to apply all rents, issues and profits
from the Property to the payment of operating expenses, real estate taxes,
insurance, capital repair items, and the payment of sums due and owing under
this Note, the Mortgage or the Related Agreements prior to any other expenditure
or distribution by Maker, (iv) the failure to account for and to turn over
security deposits (and interest required by law or agreement to be paid thereon)
or prepaid rents following the occurrence of an Event of Default under this
Note, the Mortgage or any Related Agreements, (v) the failure to timely pay real
estate taxes or any regular or special assessments affecting the Property, (vi)
the failure to maintain casualty and liability insurance as required under the
Mortgage or the Related Agreements or to apply insurance proceeds or
condemnation awards relating to the Property or other collateral in the manner
required under applicable provisions of this Note, the Mortgage or any Related
Agreements, or (vii) any modification, termination or cancellation of any lease
of all or any portion of the Property without Holder's prior written consent, if
and to the extent such consent is required under the Mortgage or the Related
Agreements and if and to the extent such modification, termination or
cancellation has a material adverse affect on the value of the Property; and

      (c)  Maker, any general partners of Maker and Guarantor shall become
personally liable for payment of the indebtedness evidenced by this Note and
performance of all other obligations of Maker under this Note, the Mortgage and
the Related Agreements upon the occurrence of any of the following: (i) fraud or
willful misrepresentation of a material fact by Maker, any general partners of
Maker or Guarantor in connection with this Note, the Mortgage or the Related
Agreements or any request for any action or consent by Holder, (ii) a Transfer
of any interest in Maker or all or any portion of the Property or any interest
therein in violation of the terms of this Note, the Mortgage or the Related
Agreements, or (iii) the incurrence by Maker of any indebtedness in violation of
the terms of this Note, the Mortgage or any Related Agreement (whether secured
or unsecured, direct or contingent), other than unsecured debt or routine trade
payables incurred in the ordinary course of business in connection with the
operation of the Property.

      In addition, Maker, any general partners of Maker and Guarantor shall be
responsible for any reasonable costs and expenses incurred by Holder in
connection with the collection of any amounts for which Maker, its general
partners, if any, and Guarantor are personally liable under this section,
including attorneys' fees and expenses, court costs, filing fees, and all other
costs and expenses incurred in connection therewith.

18.   SUCCESSORS AND ASSIGNS The provisions of this Note shall be binding upon
Maker and its legal representatives, successors and assigns and shall inure to
the benefit of any Holder and its successors and assigns. In

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the event Maker is composed of more than one party, obligations arising from
this Note are and shall be joint and several as to each such party.

19.   REMEDIES CUMULATIVE The remedies of Holder as provided in this Note, or in
the Mortgage or the Related Agreements, and the warranties contained herein or
therein shall be cumulative and concurrent, may be pursued singly, successively
or together at the sole discretion of Holder, may be exercised as often as
occasion for their exercise shall occur and in no event shall the failure to
exercise any such right or remedy be construed as a waiver or release of such
right or remedy. No remedy under this Note, conferred upon or reserved to Holder
is intended to be exclusive of any other remedy provided in this Note, the
Mortgage or the Related Agreements or provided by law, but each shall be
cumulative and shall be in addition to every other remedy given under the
Mortgage or any of the Related Agreements or hereunder or now or hereafter
existing at law or in equity or by statute.

20.   NOTICES All notices, written confirmation of wire transfers and all other
communications with respect to this Note shall be directed as follows: if to
Holder, c/o Commercial Mortgage Division, Allstate Plaza South, Suite G5C, 3075
Sanders Road, Northbrook, Illinois 60062, Attention: Servicing Manager, with a
copy to Investment Law Division, Allstate Plaza South, Suite G5A, 3075 Sanders
Road, Northbrook, Illinois 60062; if to Maker, GLR-1600 Corporate Center, LLC,
c/o Great Lakes REIT, 823 Commerce Drive, Suite 300, Oak Brook, Illinois 60523,
Attention: Chief Financial Officer with a copy to: Great Lakes REIT, 823
Commerce Drive, Suite 300, Oak Brook, Illinois 60523, Attention: General
Counsel. or at such other place as Holder or Maker may from time to time
designate in writing. All notices shall be in writing and shall be (a)
hand-delivered, (b) sent by United States express mail or by private overnight
courier, or (c) served by certified mail postage prepaid, return receipt
requested, to the appropriate address set forth above. Notices served as
provided in (a) and (b) shall be deemed to be effective upon delivery. Any
notice served by certified mail shall be deposited in the United States mail
with postage thereon fully prepaid and shall be deemed effective on the day of
actual delivery as shown by the addressee's return receipt or the expiration of
three business days after the date of mailing, whichever is earlier in time.

21.   NO ORAL MODIFICATION This Note may not be modified or discharged orally,
but only by an agreement in writing signed by the party against whom enforcement
of any waiver, modification or discharge is sought.

22.   TIME Time is of the essence with regard to the performance of the
obligations of Maker in this Note and each and every term, covenant and
condition herein by or applicable to Maker.

23.   CAPTIONS The captions and headings of the paragraphs of this Note are for
convenience only and are not to be used to interpret, define or limit the
provisions hereof.

24.   TRANSFER OF NOTE Holder may, at any time, sell, transfer or assign this
Note, the Mortgage and the Related Agreements, and any or all servicing rights
with respect to this Note, or grant participations in this Note or issue
mortgage pass-through certificates or other securities evidencing a beneficial
interest in this Note. Holder may forward to any prospective purchaser or any
rating agency rating securities all documents and information Holder now has or
may acquire, as Holder determines necessary or desirable, including, without
limitation, financial information regarding Maker, its general partners,
shareholders, members or other principals.

25.   REPLACEMENT NOTE Upon receipt of evidence reasonably satisfactory to Maker
of the loss, theft, destruction or mutilation of this Note, and in the case of
any such loss, theft or destruction, upon delivery of an indemnity agreement
reasonably satisfactory to Maker or, in the case of any such mutilation, upon
surrender and cancellation of this Note, Maker will execute and deliver to
Holder in lieu thereof, a replacement note dated as of the date of this Note,
identical in form and substance to this Note and upon such execution and
delivery all references in the Mortgage to this Note shall be deemed to refer to
such replacement note.

      IN WITNESS WHEREOF, Maker has caused this Mortgage Note to be duly
executed on the date first above written.

                             MAKER:

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                GLR - 1600 CORPORATE CENTER, LLC, a Delaware
                limited liability company

                       By:      GREAT LAKES REIT, L.P., a Delaware
limited partnership, its sole member

                            By:      GREAT LAKES REIT, a
                                     Maryland real estate investment trust, its
                                     sole general partner

                            By:
                                -------------------------------------
                                     Its:
                                          ------------------------------

                                       61
<Page>

EXHIBIT A

BASIS POINT ADJUSTMENT TABLE

<Table>
<Caption>
U.S Treasury Bond        Basis Point      U.S. Treasury Bond        Basis Point
  or Note Yield           Adjustment         or Note Yield           Adjustment
-------------------      -----------    -----------------------     -----------
<S>                      <C>            <C>                         <C>

</Table>

                                       62
<Page>

<Table>
 <S>                             <C>
     0 -  1.55                   .0
  1.56 -  2.69                   .01
  2.70 -  3.48                   .02
  3.49 -  4.12                   .03
  4.13 -  4.68                   .04
  4.69 -  5.17                   .05
  5.18 -  5.63                   .06
  5.64 -  6.05                   .07
  6.06 -  6.44                   .08
  6.45 -  6.82                   .09
  6.83 -  7.17                   .10
  7.18 -  7.51                   .11
  7.52 -  7.83                   .12
  7.84 -  8.14                   .13
  8.15 -  8.44                   .14
  8.45 -  8.73                   .15
  8.74 -  9.02                   .16
  9.03 -  9.29                   .17
  9.30 -  9.55                   .18
  9.56 -  9.81                   .19
  9.82 - 10.07                   .20
 10.08 - 10.31                   .21
 10.32 - 10.55                   .22
 10.56 - 10.79                   .23
 10.80 - 11.02                   .24
 11.03 - 11.25                   .25
 11.26 - 11.47                   .26
 11.48 - 11.69                   .27
 11.70 - 11.90                   .28
 11.91 - 12.11                   .29
 12.12 - 12.32                   .30
 12.33 - 12.52                   .31
 12.53 - 12.72                   .32
 12.73 - 12.92                   .33
 12.93 - 13.12                   .34
 13.13 - 13.31                   .35
 13.32 - 13.50                   .36
 13.51 - 13.69                   .37
 13.70 - 13.87                   .38
 13.88 - 14.06                   .39
 14.07 - 14.24                   .40
</Table>

                                       63
<Page>

<Table>
 <S>                             <C>
 14.25 - 14.41                   .41
 14.42 - 14.59                   .42
 14.60 - 14.77                   .43
 14.78 - 14.94                   .44
 14.95 - 15.11                   .45
 15.12 - 15.28                   .46
 15.29 - 15.44                   .47
 15.45 - 15.61                   .48
 15.62 - 15.77                   .49
 15.78 - 15.94                   .50
 15.95 - 16.10                   .51
 16.11 - 16.26                   .52
 16.27 - 16.41                   .53
 16.42 - 16.57                   .54
 16.58 - 16.73                   .55
 16.74 - 16.88                   .56
 16.89 - 17.03                   .57
 17.04 - 17.18                   .58
 17.19 - 17.33                   .59
 17.34 - 17.48                   .60
 17.49 - 17.63                   .61
 17.64 - 17.78                   .62
 17.79 - 17.92                   .63
 17.93 - 18.07                   .64
 18.08 - 18.21                   .65
 18.22 - 18.35                   .66
 18.36 - 18.49                   .67
 18.50 - 18.63                   .68
 18.64 - 18.77                   .69
 18.78 - 18.91                   .70
 18.92 - 19.05                   .71
 19.06 - 19.18                   .72
 19.19 - 19.32                   .73
 19.33 - 19.45                   .74
 19.46 - 19.59                   .75
 19.60 - 19.72                   .76
 19.73 - 19.85                   .77
 19.86 - 19.99                   .78
 20.00 - 20.12
</Table>

                                       64