Document:

<Page>

                                                                     EXHIBIT 4.2

                       [Union Electric Company Letterhead]

                                  COMPANY ORDER

                                                                 August 22, 2002

The Bank of New York
101 Barclay Street
Floor 21W
New York, New York 10286

Ladies and Gentlemen:

     Application is hereby made to The Bank of New York, a New York banking
corporation, as trustee (the "Trustee"), under the Indenture dated as of August
15, 2002 (the "Indenture"), between Union Electric Company, a Missouri
corporation (the "Company"), and the Trustee for the authentication and delivery
of $173,000,000 aggregate principal amount of the Company's 5.25% Senior Secured
Notes due 2012 (the "Notes"), pursuant to the provisions of Article II of the
Indenture. On or after the Release Date, the Company, in its discretion, may
change the descriptive title of the Notes to delete the word "Secured" from such
descriptive title. All capitalized terms not defined herein which are defined in
the Indenture shall have the same meaning as used in the Indenture.

     In connection with this Company Order, there are delivered to you herewith
the following:

     1.   Certified copies of the resolutions adopted by the Board of Directors
          of the Company authorizing this Company Order and the issuance and
          sale of the Notes by the Company pursuant to Section 2.05(c)(1) of the
          Indenture;

     2.   Opinions of Counsel addressed to you or in which it is stated that you
          may rely pursuant to Section 2.05(c)(2) of the Indenture;

     3.   Expert's certificate pursuant to Section 2.05(c)(3) of the Indenture;

     4.   Officers' Certificate pursuant to Section 2.05(c)(4) of the Indenture;

     5.   A Global Note representing the Notes and, pursuant to Section 2.05(c)
          of the Indenture, specifying the terms of the Notes (which terms are
          incorporated by reference herein) executed on behalf of the Company in
          accordance with the terms of Section 2.05(a) of the Indenture; and

     6.   Pursuant to Section 2.05(c)(3) of the Indenture, the Company's First
          Mortgage Bonds designated "First Mortgage Bonds, Senior Notes Series
          AA" (the "First Mortgage Bonds") in the principal amount of
          $173,000,000 relating to the Notes, fully registered in the name of
          the Trustee in trust for the benefit of the Holders from time to time
          of such Notes.

<Page>

     You are hereby instructed to authenticate the Global Note representing the
Notes and deliver it to The Depository Trust Company ("DTC") or its custodian.
The Global Note representing the Notes is to be held for delivery to Banc of
America Securities LLC and Credit Suisse First Boston Corporation, on behalf of
the several underwriters, against payment therefor at the closing in respect of
the sale thereof, such closing to be held at 10:00 a.m., New York time, August
22, 2002, at the offices of Pillsbury Winthrop LLP, One Battery Park Plaza, New
York, NY 10004.

     Please acknowledge receipt of the Global Note representing the Notes, the
instructions referred to above and the supporting documentation pursuant to the
Indenture referred to above.

                                             Very truly yours,

                                             Union Electric Company
                                             (d/b/a AmerenUE)

                                             By:   /s/ Warner L. Baxter
                                                --------------------------------
                                                Name:  Warner L. Baxter
                                                Title: Senior Vice President

<PAGE>

                  CERTIFIED COPY OF RESOLUTIONS ADOPTED AT THE
                      MEETING OF THE BOARD OF DIRECTORS OF
                             UNION ELECTRIC COMPANY
                         HELD ON TUESDAY, APRIL 23, 2002

         RESOLVED, that, in substitution of that portion of the long-term debt
authorized at the December 9, 1999 meeting of the Board of Directors which
remains unissued and unsold ($563.5 million of the $750 million authorized),
this Board hereby declares it advisable that the Company issue and sell in one
or more series and in any combination up to $750 million of new securities; that
such new securities may be in the form of senior secured debt securities, first
mortgage bonds, senior unsecured debt securities, subordinated debt securities,
trust preferred securities and related guarantees, and evidences of indebtedness
to support the issuance and sale of bonds or notes by the State Environmental
Improvement and Energy Resources Authority - Missouri (the "Authority"), or by a
combination thereof (the "New Securities"), in amounts to be determined, and
with such terms and provisions as shall be later determined by the officers of
the Company subject to approval or ratification by the Board; and that such New
Securities may be issued, sold, or offered for sale in such manner, by private
placement or by public offering, through negotiation or by competitive bidding
or otherwise, at such time or times, all as may be determined by the officers of
the Company in their discretion or as may be required by contractual arrangement
or by law; and further

         RESOLVED, that the officers of the Company be and hereby are authorized
and directed to use the proceeds of the New Securities in any one or a
combination of the following manners: (i) in connection with the payment at
maturity or the redemption, refunding, refinancing or purchase of the Company's
outstanding long-term debt, including without limitation, the Company's first
mortgage bonds; and (ii) for general corporate purposes, including without
limitation, the repayment of short-term debt incurred to finance construction
expenditures and other working capital needs; and further

         RESOLVED, that, if it is determined by the officers of the Company to
be in the best interests of the Company, such officers be and hereby are
authorized and directed, in their discretion, to replace portions of the
Company's debt deemed appropriate, all in accordance with the terms of any
applicable covenants, and to do or cause to be done all such acts and things as
they, with the advice of counsel, may deem necessary or advisable in order to
carry into effect the purposes and intent of this resolution, including the
deposit of the funds necessary for such replacement(s) and providing for
requisite notifications; and further

         RESOLVED, that the officers of this Company be and hereby are
authorized and directed to make, with the assistance of counsel and at such time
or times as they may deem advisable, applications, registration statements, or
other required filings to the Public Service Commission of Missouri and the
Illinois Commerce Commission, for approval of the issue and sale by this Company
of up to $750 million principal amount of New Securities heretofore authorized
at this meeting, and for such other approvals as may be required in connection
therewith; and that such officers be and

<PAGE>

                                       -2-

hereby are authorized to execute, acknowledge and deliver all such instruments
and to do all such other acts and things as they may deem necessary or desirable
in connection therewith; and further

         RESOLVED, that the officers of this Company be and hereby are
authorized and directed to proceed, with the assistance of counsel and at such
time or times as they may deem advisable, with the preparation of any
registration statement and prospectus required under the Securities Act of 1933
for the issue and sale of up to $750 million principal amount of New Securities
of the Company; that the proper officers and directors of this Company be and
hereby are authorized to execute any such registration statement and such
amendments thereto as they may deem necessary or desirable; that the name of any
officer or director of the Company, authorized or required to sign any such
registration statement or any amendment thereto, may be signed by C. W. Mueller
and/or Gary L. Rainwater and/or Warner L. Baxter and/or Steven R. Sullivan,
and/or the duly appointed substitute thereof, pursuant to duly executed powers
of attorney providing said named persons with, among other things, full power of
substitution and revocation; that the officers of this Company be and hereby are
authorized to file any such registration statement and prospectus and amendments
thereto with the Securities and Exchange Commission when executed by or on
behalf of the proper executive officers and the directors of the Company; and
that Warner L. Baxter and Steven R. Sullivan be and hereby are designated as the
persons authorized to receive notices and communications from the Securities and
Exchange Commission with respect to any such registration statement; and further

         RESOLVED, that the officers of this Company be and hereby are
authorized to file, in their discretion and with the assistance of counsel, any
application to the New York Stock Exchange, Inc., that may be required for
listing the New Securities and any agreements required by the Exchange in
connection with any such listing; and that C. W. Mueller, Gary L. Rainwater,
Warner L. Baxter and Steven R. Sullivan, or any of them, be and hereby is
designated by the Company to appear before said Exchange, with authority to
make, with the assistance of counsel, such changes in any such application, or
in any agreements relative thereto, as may be necessary to conform with the
requirements for listing; and further

         RESOLVED, that the officers of this Company be and hereby are
authorized to file, in their discretion and with the assistance of counsel, with
the Securities and Exchange Commission under the Securities Exchange Act of
1934, any application that may be required for registration on the New York
Stock Exchange, Inc. of the New Securities; and that Warner L. Baxter and Steven
R. Sullivan be and hereby are designated as the persons authorized to receive
notices and communications from the Securities and Exchange Commission in
connection with any such application; and further

         RESOLVED, that it is desirable and in the best interest of this Company
that its securities be qualified or registered for sale in various states; that
the Chairman or the President or any Senior Vice President or any Vice President
and the Secretary or an Assistant Secretary hereby are authorized to determine
the states in which

<PAGE>

                                      -3-

appropriate action shall be taken to qualify or register for sale all or such
part of the securities of this Company as said officers may deem advisable; that
said officers are hereby authorized to perform on behalf of this Company any and
all such acts as they may deem necessary or advisable in order to comply with
the applicable laws of any such states, and in connection therewith to execute
and file all requisite papers and documents, including, but not limited to,
applications, reports, surety bonds, irrevocable consents and appointments of
attorneys for service or process; and the execution by such officers of any such
paper or document or the doing by them of any act in connection with the
foregoing matters shall conclusively establish their authority therefor from
this Company and the approval and ratification by this Company of the papers and
documents so executed and the action so taken; and further

         RESOLVED, that the officers of the Company be and hereby are authorized
to negotiate with such parties as they deem appropriate and to prepare any
necessary documents or instruments required in connection with the issue and
sale of the New Securities; and further

         RESOLVED, that the officers of this Company be and hereby are
authorized and directed to do or cause to be done all such other acts and things
as they may deem necessary or desirable in order to carry into effect the
purposes and intent of the foregoing resolutions.

                                    I hereby certify that the foregoing is a
                           true and correct copy of resolutions adopted at the
                           meeting of the Board of Directors of Union Electric
                           Company, held on Tuesday, April 23, 2002 at the
                           General Office Building of the Company, St. Louis,
                           Missouri, and that such resolutions are still in full
                           force and effect.

                                               /s/ Ronald K. Evans

                                               Assistant Secretary

<PAGE>

                  CERTIFIED COPY OF RESOLUTIONS ADOPTED AT THE
                      MEETING OF THE BOARD OF DIRECTORS OF
                             UNION ELECTRIC COMPANY
                        HELD ON THURSDAY, AUGUST 15, 2002

         WHEREAS, by resolutions previously adopted on April 23, 2002 (the
"Prior Resolutions"), the Board of Directors gave approval to the issuance and
sale by the Company in one or more series and in any combination, up to an
aggregate of $750 million of new securities in the form of senior secured debt
securities, first mortgage bonds, senior unsecured debt securities, subordinated
debt securities, trust preferred securities and related guarantees, and
evidences of indebtedness to support the issuance and sale of bonds or notes by
the State Environmental Improvement and Energy Resources Authority-Missouri
(collectively, the "New Securities") in amounts to be determined, and with terms
and provisions as shall be later determined by the officers of the Company
subject to approval or ratification by the Board; and

         WHEREAS, pursuant to the Prior Resolutions, the Company proposes to
issue and sell New Securities in the form of $173,000,000 principal amount of
senior notes to be secured by an underlying issue of the Company's First
Mortgage Bonds with substantially similar terms (the "Senior Secured Notes");
and

         WHEREAS, in accordance with the terms of the Prior Resolutions certain
further approvals of the Board are required prior to the issuance and sale of
such Senior Secured Notes; and

         NOW, THEREFORE, BE IT RESOLVED, by the Board of Directors of the
Company, in accordance with the Prior Resolutions, as follows:

         1.       The Company is authorized to issue and sell $173,000,000 of
                  Senior Secured Notes for the purposes of (i) redeeming prior
                  to maturity its $125 million principal amount of 8.75% First
                  Mortgage Bonds due December 1, 2021, (ii) redeeming its
                  $41,437,500 Series $1.735 Preferred Stock at par, and (iii)
                  paying associated redemption premium and a portion of the
                  costs of the issuance of the Senior Secured Notes.

         2.       The Company shall issue and sell $173,000,000 of Senior
                  Secured Notes designated "5.25% Senior Secured Notes due
                  2012". The Senior Secured Notes will be issued under and
                  pursuant to an Indenture dated as of August 15, 2002 (as
                  amended and supplemented, including by a Company Order
                  establishing the terms of the Senior Secured Notes, the "Note
                  Indenture") between the Company and The Bank of New York, as
                  trustee (the "Trustee"). The Senior Secured Notes shall have a
                  price to the public of 99.883% of their principal amount and
                  shall bear an interest rate of 5.25% per annum payable
                  semi-annually on March 1 and September 1 of each year,
                  beginning March 1, 2003. Interest on the Senior Secured Notes
                  will accrue from the date of original issuance. The Company
                  may redeem all or part of the Senior Secured Notes at anytime
                  at the greater of (a) their principal amount and (b) the

<PAGE>

                                      -5-

                  discounted present value of the remaining scheduled payments
                  of principal and interest plus accrued and unpaid interest as
                  more specifically set forth therein. The Senior Secured Notes
                  shall have a 10 year maturity. The Senior Secured Notes shall
                  have such other terms as are set forth in the Note Indenture.
                  The Senior Secured Notes shall be executed by the Company, and
                  authenticated and delivered by the Trustee, pursuant to the
                  terms and conditions set forth in the Note Indenture. The
                  issuance and sale by the Company of the Senior Secured Notes,
                  pursuant to the terms hereof and the Note Indenture, and the
                  Underwriting Agreement and the Pricing Agreement referred to
                  below is hereby authorized and approved. The form of the
                  Senior Secured Notes and Trustee's Certificate to be endorsed
                  on the Senior Secured Notes under the Note Indenture shall be
                  in the form thereof as set forth in the Note Indenture, which
                  form is approved.

         3.       As security for the Senior Secured Notes, the Company shall
                  issue to the Trustee a series of its First Mortgage Bonds to
                  be designated "First Mortgage Bonds, Senior Notes Series AA"
                  (the "Senior Notes Series AA Bonds") in the same aggregate
                  principal amount and having the same stated interest rate,
                  maturity and redemption provisions as the Senior Secured Notes
                  to which they relate pursuant to the provisions of the
                  Mortgage Indenture and the New Supplemental Indenture referred
                  to below. The Senior Notes Series AA Bonds will be issued
                  under and pursuant to the Company's Indenture of Mortgage and
                  Deed of Trust, dated June 15, 1937, executed by the Company to
                  The Bank of New York, as successor Trustee (the "Mortgage
                  Trustee"), as heretofore amended and supplemented by various
                  supplemental indentures (the "Mortgage Indenture"), and as to
                  be further amended and supplemented by a supplemental
                  indenture dated August 15, 2002 (the "New Supplemental
                  Indenture"). Upon the retirement of all first mortgage bonds
                  of the Company outstanding under the Mortgage Indenture (other
                  than the Senior Notes Series AA Bonds or other first mortgage
                  bonds of the Company issued as security for senior notes
                  issued under the Note Indenture), the Senior Secured Notes
                  will cease to be secured by the Senior Notes Series AA Bonds,
                  will become unsecured and unsubordinated obligations of the
                  Company and will rank on a parity with other unsecured and
                  unsubordinated indebtedness of the Company unless otherwise
                  secured pursuant to the terms of the Senior Secured Notes and
                  the Note Indenture.

         4.       The Chairman and Chief Executive Officer or the President or
                  any Vice President or the Treasurer of the Company is hereby
                  authorized and directed to execute, deliver and perform, or
                  cause to be executed, delivered or performed, on behalf of the
                  Company, an Underwriting Agreement, to be dated the date of
                  execution thereof, between the Company and Banc of America
                  Securities LLC and Credit Suisse First Boston Corporation, as
                  representatives of the several underwriters named therein, and
                  a Pricing Agreement, to be dated the date of execution

<PAGE>

                                      -6-

                  thereof, between the Company and Banc of America Securities
                  LLC and Credit Suisse First Boston Corporation, as
                  representatives of the several underwriters named therein (the
                  "Underwriters"), providing for the sale by the Company, and
                  the several purchases by the Underwriters from the Company, of
                  the Senior Secured Notes. The Senior Secured Notes shall be
                  sold to the Underwriters at 99.233% of the principal amount of
                  the Senior Secured Notes, which will reflect an underwriting
                  commission to the Underwriters of $1,124,500 (or 0.65% of the
                  principal amount of the Senior Secured Notes) and proceeds to
                  the Company of $171,673,090 (before expenses). The
                  Underwriting Agreement and the Pricing Agreement each is to be
                  in the form submitted to this meeting, with such changes or
                  insertions therein or modifications thereof as the officer of
                  the Company executing the same may approve, such approval to
                  be conclusively evidenced by his or her execution thereof.

         5.       The Company shall issue and sell the Senior Secured Notes as
                  secured by the Senior Notes Series AA Bonds as stated above
                  and in accordance with the terms of the Underwriting Agreement
                  and the Pricing Agreement.

         6.       The form of the Prospectus Supplement (including the
                  accompanying prospectus dated August 15, 2002), a copy of
                  which was presented to this meeting, reflecting the final
                  terms of the Senior Secured Notes as stated herein is hereby
                  approved and authorized to be filed with the Securities and
                  Exchange Commission.

         7.       The Company shall execute and deliver the Note Indenture and
                  any other related orders, certificates or other documents
                  required pursuant to the terms thereof for the purpose of
                  setting forth the form and substance and the terms, provisions
                  and characteristics of the Senior Secured Notes. The Note
                  Indenture shall be in the form of, and shall contain the terms
                  and provisions set forth in, the draft of said document
                  presented at this meeting, which form is hereby approved, but
                  with changes and insertions, if any, in said document as the
                  officers of the Company executing said document may approve,
                  such approval of said officers to be conclusively evidenced by
                  their execution of said document on behalf of the Company; and
                  the Chairman and Chief Executive Officer or the President or
                  any Vice President and the Secretary (or any Assistant
                  Secretary) of the Company are authorized and directed to
                  execute and deliver, or cause to be executed and delivered,
                  and attest, respectively, any orders, certificates or other
                  documents required pursuant to the terms of the Note Indenture
                  on behalf of the Company, and The Bank of New York, as Trustee
                  under the Note Indenture, is authorized and requested, to the
                  extent required, to join with the Company in the execution of
                  said documents.

<PAGE>

                                      -7-

         8.       The Company shall execute and deliver the New Supplemental
                  Indenture to the Mortgage Indenture and any other related
                  applications, certificates or other documents pursuant to the
                  terms thereof for the purpose of (a) setting forth the form
                  and substance and terms, provisions and characteristics of the
                  Senior Notes Series AA Bonds and (b) amending or modifying
                  certain of the terms and provisions of the Mortgage Indenture
                  to the extent set forth in the New Supplemental Indenture. The
                  New Supplemental Indenture shall be in the form of and shall
                  contain the terms and provisions set forth in, the draft of
                  said document presented at this meeting, which form is hereby
                  approved, but with changes and insertions, if any, in said
                  document as the officers of the Company executing said
                  document may approve, such approval of said officers to be
                  conclusively evidenced by their execution of said document on
                  behalf of the Company; and the Chairman and Chief Executive
                  Officer or the President or any Vice President and the
                  Secretary (or any Assistant Secretary) of the Company are
                  authorized and directed to execute and deliver, or cause to be
                  executed and delivered, and attest, respectively, the New
                  Supplemental Indenture and any other related applications,
                  certificates or other documents pursuant to the terms thereof
                  on behalf of the Company and The Bank of New York, as
                  successor Mortgage Trustee, under the Mortgage Indenture, are
                  authorized and requested to join with the Company in the
                  execution of said document.

         9.       As described in paragraph 3 above, one series of bonds (to
                  wit: the Senior Notes Series AA Bonds) to be issued by the
                  Company pursuant to the terms of, and to be secured by, the
                  Mortgage Indenture and the New Supplemental Indenture and
                  which shall be executed, authenticated and issued only in the
                  form of registered bonds without coupons, registered in the
                  name of the Trustee as security for the Senior Secured Notes
                  are hereby created, authorized and approved. The Mortgage
                  Trustee's Certificate to be endorsed on the Senior Notes
                  Series AA Bonds under the Mortgage Indenture shall be in the
                  form thereof set forth in the New Supplemental Indenture,
                  which form is approved.

         10.      The Senior Notes Series AA Bonds shall be authenticated
                  pursuant to the provisions of Sections 3 and 6 of Article III
                  of the Mortgage Indenture.

         11.      The Senior Notes Series AA Bonds shall be executed and issued
                  on behalf of the Company, and authenticated by the Trustee or
                  its agents under the Mortgage Indenture, in the form of
                  registered bonds without coupons in the denomination of $1,000
                  each or any multiple thereof, registered in the name of the
                  Trustee as security for the Senior Secured Notes and sealed
                  with the corporate seal of the Company, in the manner provided
                  in or permitted by Article II of the Mortgage Indenture and as
                  provided in Article I of the New Supplemental Indenture, and
                  the provisions of said Article I of the New Supplemental
                  Indenture

<PAGE>

                                      -8-

                  with respect to the execution of said bonds by the manual or
                  facsimile signature of C. W. Mueller as Chairman and Chief
                  Executive Officer, or G. L. Rainwater as President, or W. L.
                  Baxter as Senior Vice President, or J. E. Birdsong as Vice
                  President and Treasurer and S. R. Sullivan as Secretary, or G.
                  L. Waters or R. K. Evans as Assistant Secretary, and the
                  placing of the corporate seal of the Company on said bonds are
                  adopted and are incorporated in and made a part of this
                  resolution with the same force and effect as if set forth at
                  length herein.

         12.      The specimen copy of a registered bond without coupons of
                  Senior Notes Series AA Bonds presented at this meeting, which
                  is in the form of such bond set forth in the New Supplemental
                  Indenture, is approved and shall be filed with the minutes of
                  this meeting; and to the extent executed with facsimile
                  signatures said facsimile signatures of G. L. Rainwater, as
                  President, and S. R. Sullivan, as Secretary, of the Company,
                  which are imprinted or reproduced on the Senior Notes Series
                  AA Bonds as shown by said specimen copy, are approved and
                  adopted by the Company.

         13.      C. W. Mueller as Chairman and Chief Executive Officer, or G.
                  L. Rainwater as President, or W. L. Baxter as Senior Vice
                  President, or J. E. Birdsong as Vice President and Treasurer
                  and S. R. Sullivan as Secretary or G. L. Waters and R. K.
                  Evans as Assistant Secretary of the Company are authorized and
                  directed to execute the Senior Notes Series AA Bonds on behalf
                  of the Company and such officers of the Company, or any of
                  them, are authorized and empowered to deliver the Senior Notes
                  Series AA Bonds for authentication to The Bank of New York, as
                  Mortgage Trustee or its agent under the Mortgage Indenture.

         14.      The Bank of New York, as Trustee under the Mortgage Indenture,
                  is authorized and requested (a) to authenticate the Senior
                  Notes Series AA Bonds pursuant to the provisions of Sections 3
                  and 6 of Article III of the Mortgage Indenture as provided
                  above, in registered form without coupons in the name of the
                  Trustee as security for the Senior Secured Notes, and (b) to
                  deliver the Senior Notes Series AA Bonds to the Trustee under
                  the Note Indenture, against receipt therefor, when duly
                  authenticated by it as such Mortgage Trustee, to or upon the
                  written order of the President or any Vice President of the
                  Company.

         15.      S. R. Sullivan, Vice President, General Counsel and Secretary
                  of the Company, and J. C. Thompson are each selected and
                  appointed by the Company as counsel and expert, respectively,
                  to give or furnish such opinions and expert's certificates, in
                  each case as may be required by the terms of the Mortgage
                  Indenture and the Note Indenture, in connection with the
                  authentication by the Mortgage Trustee under the Mortgage
                  Indenture and the issuance by the Company of the Senior Notes
                  Series AA Bonds and the authentication by the Trustee under
                  the Note Indenture and the issuance and sale by the Company of
                  the Senior

<PAGE>

                                      -9-

                  Secured Notes; and said counsel is further requested to give
                  or furnish such legal opinions with respect to the Senior
                  Secured Notes and the Senior Notes Series AA Bonds as may be
                  required by the terms of the Note Indenture, the Mortgage
                  Indenture and the Underwriting Agreement referred to above or
                  as may be appropriate in the circumstances.

         16.      The officers of the Company are authorized and directed to
                  take or cause to be taken all such actions as are necessary to
                  effect an early redemption of the outstanding principal amount
                  of the First Mortgage Bonds, 8.75% Series due 2021 and the
                  outstanding shares of Series $1.735 Preferred Stock; all in
                  accordance with the terms of the applicable indentures, the
                  Company's Restated Articles of Incorporation and the
                  applicable Certificate of Designation, Description and Terms
                  of Preferred Stock filed with the Secretary of State of the
                  State of Missouri, and to do or cause to be done all such acts
                  and things as they, with the advice of counsel, may deem
                  necessary or advisable in order to carry into effect the
                  purposes and intent of this resolution, including the deposit
                  with the trustee for such bonds of the funds necessary for
                  such redemption and providing for requisite notifications.

         17.      The officers of the Company are authorized and directed to do
                  or cause to be done all such other acts and things as they may
                  deem necessary or advisable in order to carry into effect the
                  purposes and intent of the resolutions adopted in connection
                  with the issuance and sale of the Senior Secured Notes of the
                  Company as to be secured by the Senior Notes Series AA Bonds
                  authorized at this meeting including executing a Letter of
                  Representations relating to the Senior Secured Notes with the
                  Trustee and The Depository Trust Company.

                                   I hereby certify that the foregoing is a true
                          and correct copy of resolutions adopted at the meeting
                          of the Board of Directors of Union Electric Company,
                          held on Thursday, August 15, 2002 at the General
                          Office Building of the Company, St. Louis, Missouri,
                          and that such resolutions are still in full force and
                          effect.

                                               /s/ Ronald K. Evans

                                               Assistant Secretary

<Page>

                       [Union Electric Company Letterhead]

                                 August 22, 2002

The Bank of New York
101 Barclay Street
Floor 21W
New York, NY 10286

                             UNION ELECTRIC COMPANY
                    $173,000,000 5.25% Senior Notes due 2012

Ladies and Gentlemen:

     I am Vice President, General Counsel and Secretary of Union Electric
Company, a Missouri corporation (the "Company"), and have acted as counsel to
the Company in connection with the Indenture dated as of August 15, 2002 (the
"Indenture") between you and the Company, pursuant to which the Company has
engaged you to act as trustee with respect to $173,000,000 aggregate principal
amount of its 5.25% Senior Notes due 2012 (the "Notes") on the terms and subject
to the conditions set forth in the Indenture. I address this opinion to you
pursuant to Sections 2.05(c)(2) and 15.05(a) of the Indenture. Capitalized terms
not defined herein have the meanings specified in the Indenture.

     In rendering the opinions expressed below, I have read the covenants and
conditions and the definitions relating thereto as set forth in the Indenture
with respect to the execution and delivery by the Company of the Notes. I have
examined originals, copies of originals certified to my satisfaction, of such
agreements, documents, certificates and any other statements of governmental
officials and corporate officers and such other papers and evidence as I have
deemed relevant and necessary as a basis for such opinions. I have assumed the
authenticity of all documents submitted to me and the conformity with the
original documents of any copies thereof submitted to me for my examination. I
have also relied upon the representations and warranties as to factual matters
contained in and made pursuant to the Indenture. The scope and nature of such
examination and investigation is sufficient to enable me to express an informed
opinion as set forth below.

   Pursuant to the requirements of Section 2.05(c)(2) and 15.05(a) of the
   Indenture, I am of the opinion that:

<Page>

          1.   The form of the Notes has been duly authorized and established by
or pursuant to a Board Resolution or a Company Order pursuant to a Board
Resolution in conformity with the provisions of the Indenture.

          2.   The Indenture has been duly authorized, executed and delivered by
the Company and constitutes a valid and binding obligation of the Company,
enforceable against the Company in accordance with its terms, except as may be
limited by applicable bankruptcy, insolvency, reorganization, fraudulent
conveyance, moratorium or similar laws of general application relating to or
affecting the enforcement of creditors' rights and the application of general
principles of equity (regardless of whether such application is made in a
proceeding at law or in equity) and by an implied covenant of good faith and
fair dealing and except as enforcement of provisions of the Indenture may be
limited by state laws affecting the remedies for the enforcement of the security
provided for in the Indenture.

          3.   The Company's First Mortgage Bonds designated "First Mortgage
Bonds, Senior Notes Series AA" (the "Senior Note First Mortgage Bonds") being
delivered to the Trustee in connection with the issuance of the Notes have been
duly authorized, executed and delivered, and such Senior Note First Mortgage
Bonds are valid and binding obligations of the Company, enforceable against the
Company in accordance with their terms, except as may be limited by bankruptcy,
insolvency, reorganization, fraudulent conveyance, moratorium or similar laws of
general application relating to or affecting the enforcement of creditors'
rights and the application of general principles of equity (regardless of
whether such application is made in a proceeding at law or in equity) and by an
implied covenant of good faith and fair dealing and except as enforcement of
provisions of the First Mortgage may be limited by state laws affecting remedies
for the enforcement of the security provided for in the First Mortgage; and such
Senior Note First Mortgage Bonds are entitled to the benefit of the First
Mortgage, equally and ratably, with all First Mortgage Bonds outstanding
thereunder, except as to sinking fund provisions.

          4.   The Indenture and the First Mortgage are qualified to the extent
necessary under the TIA.

          5.   The Notes have been duly authorized and executed by the Company
and, when authenticated by you and issued by the Company in accordance with the
provisions of the Indenture and delivered to and duly paid for by the purchasers
thereof, will constitute valid and binding obligations of the Company,
enforceable against the Company in accordance with their terms, except as may be
limited by bankruptcy, insolvency, reorganization, fraudulent conveyance,
moratorium or similar laws of general application relating to or affecting the
enforcement of creditors' rights and the application of general principles of
equity (regardless of whether such application is made in a proceeding at law or
in equity) and by an implied covenant of good faith and fair dealing and except
as enforcement of provisions of the Indenture may be limited by state laws
affecting remedies for the enforcement of the security provided for in the
Indenture.

<Page>

          6.   The issuance of the Notes and the delivery by the Company of the
Senior Note First Mortgage Bonds in connection therewith will not result in any
default under the Indenture or the First Mortgage.

          7.   All consents or approvals of the Missouri Public Service
Commission (or any successor agency), the Illinois Commerce Commission (or any
successor agency) and of any other federal or state regulatory agency required
in connection with the Company's execution and delivery of the Indenture, the
Notes and the Senior Note First Mortgage Bonds have been obtained and are in
full force and effect (except that no opinion is expressed as to state
securities laws).

          8.   The First Mortgage and all financing statements have been duly
filed and recorded in all places where such filing or recording is necessary for
the perfection or preservation of the lien of the First Mortgage, and the First
Mortgage constitutes a valid and perfected first lien upon the property
purported to be covered thereby, subject only to "permitted liens" and certain
"judgment liens" (each as defined in the First Mortgage) and to liens upon the
property, if any, specifically identified in the supplemental indenture related
to a Related Series of Senior Note First Mortgage Bonds prior to its
recordation.

          9.   All conditions that must be met by the Company to issue the Notes
under the Indenture have been met.

     As required by Section 15.05 of the Indenture, I further advise you as
follows:

          (a)  I have read the Indenture including without limitation the
conditions precedent provided for therein relating to the authentication and
delivery of the Notes and the definitions in the Indenture relating thereto;

          (b)  I have conferred with officers of the Company and have made such
examination as to fact and law as I deemed relevant for purposes of this
opinion; however, insofar as this opinion relates to factual matters, it is
based upon certificates of officers of the Company which are being delivered to
you herewith and representations by such officers, and I take no responsibility
for the accuracy or completeness of the statements made in such certificates or
representations;

          (c)  In my opinion, I have made such examination or investigation as
is necessary to enable me to express an informed opinion as to whether or not
such conditions precedent have been complied with; and

          (d)  I am of the opinion that the conditions precedent provided for in
the Indenture relating to the authentication and delivery of the Notes as
requested in the Company Order have been complied with.

     I am a member of the Bar of the State of Missouri and, for purposes of this
opinion, do not hold myself out as an expert on the laws of any jurisdiction
other than the State of Missouri, and to the extent set forth in the next
sentence, the State of Illinois and the United States of

<Page>

America. I regularly practice before the Illinois Commerce Commission and,
therefore, am qualified to render the opinion set forth in paragraph (7) above
as an expert on the laws of the State of Illinois for such purpose. I have, with
your consent, relied upon an opinion of even date herewith addressed to you of
Pillsbury Winthrop LLP, as to all matters in this opinion involving the
application of the laws of the State of New York.

     My opinion is addressed to you and is rendered solely for your benefit.
Accordingly, it may not be quoted, filed with any governmental authority or
other regulatory agency or otherwise circulated without my prior written
consent.

                                                    Very truly yours,

                                                    /s/ Steven R. Sullivan

<PAGE>

                              EXPERT'S CERTIFICATE

         I, James C. Thompson, a former Secretary of Union Electric Company, a
Missouri corporation (the "Company"), in connection with the Indenture dated as
of August 15, 2002 (the "Indenture") between the Company and The Bank of New
York, as trustee (the "Trustee"), and the issuance and sale by the company of
$173,000,000 aggregate principal amount of 5.25% Senior Secured Notes due 2012
(the "Senior Notes") pursuant to the Indenture, DO HEREBY CERTIFY to the Trustee
pursuant to Sections 2.05(c)(3), 4.06(a) and 15.05 of the Indenture that
(capitalized terms used herein without definition herein having the meaning set
forth in the Indenture):

         1. I am familiar with the provisions of the Indenture and the Company's
Senior Note Mortgage Bonds designated "First Mortgage Bonds, Senior Notes Series
AA" (the "Series AA Senior Note Mortgage Bonds") delivered by the Company to the
Trustee pursuant to Section 4.09 of the Indenture.

         2. The principal amount of the Series AA Senior Note Mortgage Bonds is
$173,000,000, the stated interest rate of the Series AA Senior Note Mortgage
Bonds is 5.25% and the stated maturity date of the Series AA Senior Note
Mortgage Bonds is September 1, 2012.

         3. The Series AA Senior Note Mortgage Bonds correspond to the Senior
Notes that are being issued contemporaneously herewith.

         4. The fair value to the Company of the Series AA Senior Note Mortgage
Bonds is $173,000,000.

         I have read the terms of the Indenture and the First Mortgage and have
examined the provisions of other documents that I have deemed necessary in order
to make the statements herein. I am informed of matters relevant to the
statements and opinions contained in this certificate through personal knowledge
or examination of records of the Company or reports or information furnished by
officers or employees of the Company or its affiliates having knowledge of the
relevant facts. The statements and opinions contained in this certificate are
based on such knowledge, examination and investigation.

<PAGE>

         In my opinion, I have made such examination or investigation as is
necessary to enable me to express an informed opinion regarding the fair value
of the Company of the Series AA Senior Note Mortgage Bonds, and this Certificate
complies with Sections 4.06 and 15.05 of the Indenture.

                                               /s/ James C. Thompson
                                               ------------------------------
                                               James C. Thompson

Dated:  August 22, 2002

<Page>

                            OFFICERS' CERTIFICATE OF
                             UNION ELECTRIC COMPANY

     Pursuant to Section 2.05(c)(4) of the Indenture dated as of August 15,
2002, between Union Electric Company (the "Company") and The Bank of New York
(the "Trustee") (the "Indenture," the terms defined therein being used herein as
therein defined), the undersigned, being the Vice President and Treasurer and
the President and Chief Operating Officer, respectively, of the Company, do
hereby certify that:

     1.   The Company is not, and upon authentication and delivery of
          $173,000,000 aggregate principal amount of the Company's 5.25% Senior
          Notes due 2012 (the "Notes") by the Trustee, will not be in default
          under any of the terms or covenants contained in the Indenture;

     2.   All conditions that must be met by the Company to issue the Notes
          under the Indenture have been met; and

     3.   The Company's First Mortgage Bonds designated "First Mortgage Bonds,
          Senior Notes Series AA" being delivered to the Trustee on the date
          hereof meet the requirements of Section 4.10 of the Indenture.

     In accordance with Section 15.05 of the Indenture, the undersigned further
hereby certify that:

     1.   In the opinion of the undersigned, all conditions precedent, if any,
          provided for in the Indenture (including any covenants compliance with
          which constitutes a condition precedent) relating to the
          authentication and delivery of the Notes have been complied with;

     2.   Each of the undersigned has read the covenants and conditions and the
          related definitions in the Indenture;

     3.   The statement contained in clause (1) above is based upon a reading
          and an examination of the relevant provisions of the Indenture and
          certain other information of the Company; and

     4.   In the opinion of each of the undersigned, the examination described
          in clause (3) above is sufficient to enable them to express an
          informed opinion as to the subject matter of clause (1) above.

<Page>

Executed this 22nd day of August, 2002.

                                           /s/ Gary L. Rainwater
                                    --------------------------------------------
                                    Name:  Gary L. Rainwater
                                    Title: President and Chief Operating Officer

                                           /s/ Warner L. Baxter
                                    --------------------------------------------
                                    Name:  Warner L. Baxter
                                    Title: Senior Vice President

<Page>

REGISTERED                                                            REGISTERED

                               ILL. C. C. No. 6226

     THIS NOTE IS A GLOBAL NOTE REGISTERED IN THE NAME OF THE DEPOSITARY
(REFERRED TO HEREIN) OR A NOMINEE THEREOF AND, UNLESS AND UNTIL IT IS EXCHANGED
IN WHOLE FOR THE INDIVIDUAL NOTES REPRESENTED HEREBY AS PROVIDED IN THE
INDENTURE REFERRED TO BELOW, THIS NOTE MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE
BY THE DEPOSITARY TO A NOMINEE OF THE DEPOSITARY OR BY A NOMINEE OF THE
DEPOSITARY TO THE DEPOSITARY OR ANOTHER NOMINEE OF THE DEPOSITARY OR BY THE
DEPOSITARY OR ANY SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH
SUCCESSOR DEPOSITARY. UNLESS THIS NOTE IS PRESENTED BY AN AUTHORIZED
REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY (55 WATER STREET, NEW YORK, NEW
YORK), TO THE TRUSTEE FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY
CERTIFICATE ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR SUCH OTHER NAME AS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY AND
ANY PAYMENT IS MADE TO CEDE & CO., ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR
VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL SINCE THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

                             UNION ELECTRIC COMPANY
                       5.25% SENIOR SECURED NOTE DUE 2012

CUSIP:                                          NUMBER: 1

ORIGINAL ISSUE DATE: August 22, 2002            PRINCIPAL AMOUNT: $173,000,000

INTEREST RATE: 5.25%                            MATURITY DATE: September 1, 2012

     UNION ELECTRIC COMPANY, a corporation of the State of Missouri (the
"COMPANY"), for value received hereby promises to pay to CEDE & CO. or
registered assigns, the principal sum of ONE HUNDRED SEVENTY THREE MILLION
DOLLARS ($173,000,000) on the Maturity Date set forth above, and to pay interest
thereon from August 22, 2002 or from the most recent Interest Payment Date to
which interest has been paid or duly provided for, semi-annually in arrears on
the March 1 and September 1 in each year, commencing March 1, 2003, at the per
annum Interest Rate set forth above, until the principal hereof is paid or made
available for payment. No interest shall accrue on the Maturity Date, so long as
the principal amount of this Note is paid on the Maturity Date. The interest so
payable and punctually paid or duly provided for on any such Interest Payment
Date (except for interest payable on the Maturity Date set forth above or, if
applicable, upon redemption or acceleration) will, as provided in the Indenture
(as defined below), be paid to the Person in whose name this Note is registered
at the close of business on the Regular Record Date for such interest, which
shall be the February 15 or August 15, as the case may be, next preceding such
Interest Payment Date; provided that the first Interest Payment Date for any
part of this Note, the Original Issue

<Page>

Date of which is after a Regular Record Date but prior to the applicable
Interest Payment Date, shall be the Interest Payment Date following the next
succeeding Regular Record Date; and provided that interest payable on the
Maturity Date set forth above or, if applicable, upon redemption or
acceleration, shall be payable to the Person to whom principal shall be payable.
Except as otherwise provided in the Indenture, any such interest not so
punctually paid or duly provided for shall forthwith cease to be payable to the
Holder on such Regular Record Date and shall be paid to the Person in whose name
this Note is registered at the close of business on a Special Record Date for
the payment of such defaulted interest to be fixed by the Trustee, notice
whereof shall be given to Noteholders not more than fifteen days or fewer than
ten days prior to such Special Record Date. Payment of the principal of and
interest and premium on this Note shall be payable pursuant to Section 2.12(a)
of the Indenture.

     This Note is a Global Note in respect of a duly authorized issue of 5.25%
Senior Secured Notes due 2012 (the "NOTES OF THIS SERIES", which term includes
any Global Notes representing such Notes) of the Company issued and to be issued
under an Indenture dated as of August 15, 2002, between the Company and The Bank
of New York, as trustee (the "TRUSTEE", which term includes any successor
Trustee under the Indenture) and indentures supplemental thereto (collectively,
the "INDENTURE"). Under the Indenture, one or more series of notes may be issued
and, as used herein, the term "Notes" refers to the Notes of this Series and any
other outstanding series of Notes. Reference is hereby made to the Indenture for
a more complete statement of the respective rights, limitations of rights,
duties and immunities thereunder of the Company, the Trustee and the Noteholders
and of the terms upon which the Notes are and are to be authenticated and
delivered. This Note has been issued in respect of the series designated on the
first page hereof in the aggregate principal amount of $173,000,000.

     Prior to the Release Date (as hereinafter defined), the Notes will be
secured by first mortgage bonds (the "SENIOR NOTE FIRST MORTGAGE BONDS")
delivered by the Company to the Trustee for the benefit of the Holders of the
Notes, issued under the Indenture of Mortgage or Deed of Trust, dated June 15,
1937, from the Company to The Bank of New York, as successor trustee (the
"MORTGAGE TRUSTEE"), as supplemented and modified (collectively, the "FIRST
MORTGAGE"). Reference is made to the First Mortgage and the Indenture for a
description of the rights of the Trustee as holder of the Senior Note First
Mortgage Bonds, the property mortgaged and pledged, the nature and extent of the
security and the rights of the holders of first mortgage bonds, under the First
Mortgage and the rights of the Company and of the Mortgage Trustee in respect
thereof, the duties and immunities of the Mortgage Trustee and the terms and
conditions upon which the Senior Note First Mortgage Bonds are secured and the
circumstances under which additional first mortgage bonds may be issued.

     From and after such time as all first mortgage bonds (other than Senior
Note First Mortgage Bonds) issued under the First Mortgage have been retired
through payment, redemption or otherwise at, before or after the maturity
thereof (the "Release Date"), the Senior Note First Mortgage Bonds shall cease
to secure the Notes in any manner. In certain circumstances prior to the Release
Date as provided in the Indenture, the Company is permitted to reduce the
aggregate principal amount of a series of Senior Note First Mortgage Bonds held
by the Trustee, but in no event prior to the Release Date to an amount less than
the aggregate

<Page>

outstanding principal amount of the series of Notes initially issued
contemporaneously with such Senior Note First Mortgage Bonds.

     Each Note of this Series shall be dated and issued as of the date of its
authentication by the Trustee and shall bear an Original Issue Date. Each Note
issued upon transfer, exchange or substitution of such Note shall bear the
Original Issue Date of such transferred, exchanged or substituted Note, as the
case may be.

     All or a portion of the Notes of this Series may be redeemed at the option
of the Company at any time or from time to time. The redemption price for the
Notes of this Series to be redeemed on any redemption date will be equal to the
greater of: (a) 100% of the principal amount of the Notes of this Series being
redeemed on the redemption date; or (b) the sum of the present values of the
remaining scheduled payments of principal and interest on the Notes of this
Series being redeemed on that redemption date (not including any portion of any
payments of interest accrued to the redemption date) discounted to the
redemption date on a semiannual basis at the Adjusted Treasury Rate (as defined
below) plus 20 basis points, as determined by the Reference Treasury Dealer (as
defined below); plus, in each case, accrued and unpaid interest thereon to the
redemption date. Notwithstanding the foregoing, installments of interest on
Notes of this Series that are due and payable on Interest Payment Dates falling
on or prior to a redemption date will be payable on the Interest Payment Date to
the Holder of this Note as of the close of business on the relevant Regular
Record Date. The redemption price will be calculated on the basis of a 360-day
year consisting of twelve 30-day months.

     The Company shall mail notice of any redemption at least 30 days but not
more than 60 days before the redemption date to each Holder of the Notes of this
Series to be redeemed. Unless the Company defaults in payment of the redemption
price, on and after the redemption date, interest will cease to accrue on the
Notes of this Series or portions thereof called for redemption.

     "ADJUSTED TREASURY RATE" means, with respect to any redemption date, the
rate per annum equal to the semiannual equivalent yield to maturity of the
Comparable Treasury Issue, assuming a price for the Comparable Treasury Issue
(expressed as a percentage of its principal amount) equal to the Comparable
Treasury Price for such redemption date.

     "COMPARABLE TREASURY ISSUE" means the United States Treasury security
selected by the Reference Treasury Dealer as having a maturity comparable to the
remaining term of the Notes of this Series to be redeemed that would be
utilized, at the time of selection and in accordance with customary financial
practice, in pricing new issues of corporate debt securities of comparable
maturity to the remaining term of such Notes of this Series.

     "COMPARABLE TREASURY PRICE" means, with respect to any redemption date, (A)
the average of the Reference Treasury Dealer Quotations for such redemption
date, after excluding the highest and lowest such Reference Treasury Dealer
Quotations, or (B) if the Trustee obtains fewer than three such Reference
Treasury Dealer Quotations, the average of all such quotations, or (C) if only
one Reference Treasury Dealer Quotation is received, such quotation.

<Page>

     "REFERENCE TREASURY DEALER" means (A) Banc of America Securities LLC or
Credit Suisse First Boston Corporation (or their respective affiliates which are
Primary Treasury Dealers), and their respective successors; provided, however,
that if any of the foregoing shall cease to be a primary U.S. Government
securities dealer in New York City (a "Primary Treasury Dealer"), the Company
shall substitute therefor another Primary Treasury Dealer; and (B) any other
Primary Treasury Dealer(s) selected by the Trustee after consultation with the
Company.

     "REFERENCE TREASURY DEALER QUOTATIONS" means, with respect to each
Reference Treasury Dealer and any redemption date, the average, as determined by
the Trustee, of the bid and asked prices for the Comparable Treasury Issue
(expressed in each case as a percentage of its principal amount) quoted in
writing to the Trustee by such Reference Treasury Dealer at 5:00 p.m. (New York
City time) on the third Business Day preceding such redemption date.

     Interest payments for this Note shall be computed and paid on the basis of
a 360-day year of twelve 30-day months (and for any partial periods shall be
calculated on the basis of the number of days elapsed in a 360-day year of
twelve 30-day months). If any Interest Payment Date or date on which the
principal of this Note is required to be paid is not a Business Day, then
payment of principal, premium, if any, or interest need not be made on such date
but may be made on the next succeeding Business Day with the same force and
effect as if made on such Interest Payment Date or date on which the principal
of this Note is required to be paid and, in the case of timely payment thereof,
no interest shall accrue for the period from and after such Interest Payment
Date or the date on which the principal of this Note is required to be paid.

     The Company, at its option, and subject to the terms and conditions
provided in the Indenture, will be discharged from any and all obligations in
respect of the Notes (except for certain obligations including obligations to
register the transfer or exchange of Notes, replace stolen, lost or mutilated
Notes, maintain paying agencies and hold monies for payment in trust, all as set
forth in the Indenture) if the Company deposits with the Trustee money, U.S.
Government Obligations which through the payment of interest thereon and
principal thereof in accordance with their terms will provide money, or a
combination of money and U.S. Government Obligations, in any event in an amount
sufficient, without reinvestment, to pay all the principal of and any premium
and interest on the Notes on the dates such payments are due in accordance with
the terms of the Notes.

     If an Event of Default shall occur and be continuing, the principal of and
interest on the Notes may be declared due and payable in the manner and with the
effect provided in the Indenture and, upon such declaration, the Trustee shall
demand the redemption of the Senior Note First Mortgage Bonds to the extent
provided in the Indenture.

     The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modifications of the rights and obligations of the
Company and the rights of the Noteholders under the Indenture at any time by the
Company and the Trustee with the consent of the Holders of not less than a
majority in principal amount of the outstanding Notes. Any such consent or
waiver by the Holder of this Note shall be conclusive and binding upon such
Holder and upon all future Holders of this Note and of any Note issued upon the
registration of transfer

<Page>

hereof or in exchange therefor or in lieu thereof whether or not notation of
such consent or waiver is made upon this Note.

     As set forth in and subject to the provisions of the Indenture, no Holder
of any Notes will have any right to institute any proceeding with respect to the
Indenture or for any remedy thereunder unless such Holder shall have previously
given to the Trustee written notice of a continuing Event of Default with
respect to such Notes, the Holders of not less than a majority in principal
amount of the outstanding Notes affected by such Event of Default shall have
made written request and offered reasonable indemnity to the Trustee to
institute such proceeding as Trustee and the Trustee shall have failed to
institute such proceeding within 60 days; provided that such limitations do not
apply to a suit instituted by the Holder hereof for the enforcement of payment
of the principal of and any premium or interest on this Note on or after the
respective due dates expressed here.

     No reference herein to the Indenture and to provisions of this Note or of
the Indenture shall alter or impair the obligation of the Company, which is
absolute and unconditional, to pay the principal of and any premium and interest
on this Note at the times, places and rates and the coin or currency prescribed
in the Indenture.

     As provided in the Indenture and subject to certain limitations therein set
forth, this Note may be transferred only as permitted by the legend hereto and
the provisions of the Indenture.

     The Indenture and the Notes shall be governed by, and construed in
accordance with, the laws of the State of New York without regard to conflicts
of law principles thereof.

     Unless the certificate of authentication hereon has been executed by the
Trustee, directly or through an Authenticating Agent by manual signature of an
authorized officer, this Note shall not be entitled to any benefit under the
Indenture or be valid or obligatory for any purpose.

     All terms used in this Note which are defined in the Indenture shall have
the meanings assigned to them in the Indenture unless otherwise indicated
herein.

<Page>

     IN WITNESS WHEREOF, the Company has caused this instrument to be duly
executed.

                                           UNION ELECTRIC COMPANY

                                           By:      /s/ Warner L. Baxter
                                              ----------------------------------

                                           Title:   Senior Vice President
                                                 -------------------------------

                                           Attest:        /s/ G. L. Waters
                                                  ------------------------------

                                           Title:   Assistant Secretary
                                                 -------------------------------

TRUSTEE'S CERTIFICATE
OF AUTHENTICATION

Dated: August 22, 2002

This Note is one of the Notes of the series herein
designated, described or provided for in the within-
mentioned Indenture.

The Bank of New York, AS TRUSTEE

By:    /s/ Albert Lundy
   -----------------------------------
     AUTHORIZED SIGNATORY
     As Agent for The Bank of New York

<Page>

                                  ABBREVIATIONS

     The following abbreviations, when used in the inscription on the face of
this instrument, shall be construed as though they were written out in full
according to applicable laws or regulations:

TEN COM -- as tenants in common                 UNIF GIFT
                                                MIN ACT - ____ Custodian _______
                                                         (Cust)          (Minor)
TEN ENT -- as tenants by the
entireties                                      Under Uniform Gifts to Minors

JT TEN -- as joint tenants with right
of survivorship and not as tenants in
common                                          --------------------------------
                                                             State

                    Additional abbreviations may also be used
                          though not in the above list.

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

               FOR VALUE RECEIVED the undersigned hereby sell(s),
                         assign(s) and transfer(s) unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
IDENTIFYING NUMBER OF ASSIGNEE

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

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

--------------------------------------------------------------------------------
                   Please print or typewrite name and address
                      including postal zip code of assignee

----------------------------------------
the within note and all rights
thereunder, hereby irrevocably
constituting and appointing attorney to
transfer said note on the books of the
Company, with full power of substitution
in the premises.
Dated:
      ------------------------

                              -----------------------------------------------
                              NOTICE: The signature to this assignment must
                              correspond with the name as written upon the face
                              of the within instrument in every particular,
                              without alteration or enlargement or any change
                              whatever.

                              Signature(s) must be guaranteed by a financial
                              institution that is a member of the Securities
                              Transfer Agents Medallion Program ("STAMP"), the
                              Stock Exchange Medallion Program ("SEMP") or the
                              New York Stock Exchange, Inc. Medallion Signature
                              Program("MSP").

<Page>

No. 1                                                               $173,000,000

                               ILL. C. C. No. 6226

 NOTWITHSTANDING ANY PROVISIONS HEREOF OR IN THE ORIGINAL INDENTURE THIS BOND IS
 NOT ASSIGNABLE OR TRANSFERABLE EXCEPT AS PERMITTED OR REQUIRED BY SECTION 4.04
  OF THE INDENTURE DATED AS OF AUGUST 15, 2002, BETWEEN UNION ELECTRIC COMPANY
                      AND THE BANK OF NEW YORK, AS TRUSTEE.

                             UNION ELECTRIC COMPANY
             (Incorporated under the laws of the State of Missouri)
                  First Mortgage Bonds, Senior Notes Series AA

     UNION ELECTRIC COMPANY, a corporation organized and existing under the laws
of the State of Missouri (hereinafter called the "Company", which term shall
include any successor corporation as defined in the Amended Indenture referred
to on the reverse hereof), for value received, hereby promises to pay to The
Bank of New York, as trustee under the Senior Note Indenture hereinafter
referred to, or registered assigns, the sum of ONE HUNDRED SEVENTY THREE MILLION
Dollars, on the 1st day of September, 2012 in any coin or currency of the United
States of America which at the time of payment is legal tender for public and
private debts, and to pay interest thereon, in like coin or currency, at the
rate of FIVE AND ONE QUARTER per centum (5.25%) per annum, payable
semi-annually, on March 1 and September 1 in each year until maturity,
commencing March 1, 2003, and at maturity or, if the Company shall default in
the payment of the principal hereof, until the Company's obligation with respect
to the payment of such principal shall be discharged as provided in the Amended
Indenture referred to on the reverse hereof. Such interest shall be payable from
the March 1 or September 1, as the case may be, next preceding the date hereof
to which interest has not been paid, unless the date hereof is a March 1 or
September 1 to which interest has been paid, in which case from the date hereof,
or unless the date hereof is prior to the first payment of interest, in which
case from August 22, 2002. The interest so payable will be paid to the person in
whose name this Bond, or the Bond in exchange or substitution for which this
Bond shall have been issued, shall have been registered at the close of business
on the February 15 or August 15, as the case may be, next preceding the date of
payment, subject to certain exceptions set forth in the Amended Indenture. The
principal of, and interest and premium, if any, on, this Bond are payable, in
immediately available funds, at the office of the Senior Note Trustee
hereinafter referred to.

     Under an Indenture dated as of August 15, 2002 (the "Senior Note
Indenture") between the Company and The Bank of New York, as trustee (the
"Senior Note Trustee"), the Company will issue, concurrently with the issuance
of this Bond, an issue of notes under the Senior Note Indenture entitled "5.25%
Senior Secured Notes due 2012" (the "Senior Notes"). Pursuant to Article IV of
the Senior Note Indenture, this Bond is issued to the Senior Note Trustee to
secure any and all obligations of the Company under the Senior Notes and any
other series of senior notes from time to time outstanding under the Senior Note
Indenture. Payment of principal of, or

<Page>

premium, if any, or interest on, the Senior Notes shall constitute payments on
this Bond as further provided herein and in the Supplemental Indenture dated
August 15, 2002 pursuant to which this Bond has been issued (the "Supplemental
Indenture").

     Upon any payment of the principal of, premium, if any, and interest on, all
or any portion of the Senior Notes, whether at maturity or prior to maturity by
redemption or otherwise or upon provision for the payment thereof having been
made in accordance with Section 5.01(a) of the Senior Note Indenture, a
principal amount of this Bond equal to the principal amount of such Senior Notes
and having both a corresponding maturity date and interest rate shall, to the
extent of such payment of principal, premium, if any, and interest, be deemed
paid and the obligation of the Company thereunder to make such payment shall be
discharged to such extent and, in the case of the payment of principal (and
premium, if any), such bonds shall be surrendered to the Company for
cancellation as provided in Section 4.08 of the Senior Note Indenture. The
Trustee (as hereinafter defined) may at anytime and all times conclusively
assume that the obligation of the Company to make payments with respect to the
principal of and premium, if any, and interest on, the Senior Notes, so far as
such payments at the time have become due, has been fully satisfied and
discharged pursuant to the foregoing sentence unless and until the Trustee shall
have received a written notice from the Senior Note Trustee signed by one of its
officers stating (i) that timely payment of principal, or premium or interest
on, the Senior Notes has not been made, (ii) that the Company is in arrears as
to the payments required to be made by it to the Senior Note Trustee pursuant to
the Senior Note Indenture, and (iii) the amount of the arrearage.

     For purposes of Section 4.09 of the Senior Note Indenture, this Bond shall
be deemed to be the "Related Series of Senior Note First Mortgage Bonds" in
respect of the Senior Notes.

     This Bond shall not be entitled to any benefit under the Amended Indenture
or any indenture supplemental thereto, or become valid or obligatory for any
purpose, until The Bank of New York, the Trustee under the Amended Indenture, or
a successor trustee thereto under the Amended Indenture, or an agent therefor,
shall have signed the form of certificate endorsed hereon.

     The provisions of this Bond are continued on the reverse hereof and such
continued provisions shall for all purposes have the same effect as though fully
set forth at this place.

<Page>

     IN WITNESS WHEREOF, Union Electric Company has caused this Bond to be
signed in its name by its Chairman of the Board or President or a Vice President
by manual signature or a facsimile thereof, and its corporate seal (or a
facsimile thereof) to be hereto affixed and attested by its Secretary or an
Assistant Secretary by manual signature or a facsimile thereof.

     Dated,

                                         UNION ELECTRIC COMPANY,

                                         By   /s/ Warner L. Baxter
                                           ---------------------------------
                                                  Senior Vice President

[CORPORATE SEAL]

Attest:
          /s/ G. L. Waters
------------------------------
Assistant Secretary

     This Bond is one of the Bonds, of the series designated therein, described
in the within-mentioned Amended Indenture and Supplemental Indenture of August
15, 2002.

                                         THE BANK OF NEW YORK,
                                         as TRUSTEE

                                         By    /s/ Albert Lundy
                                           -------------------------------------
                                               Authorized Officer
                                               As Agent for The Bank of New York

<Page>

                                [REVERSE OF BOND]
     This Bond is one of a duly authorized issue of Bonds of the Company (herein
called the "Bonds"), in unlimited aggregate principal amount, of the series
hereinafter specified, all issued and to be issued under and equally secured by
the indenture of mortgage and deed of trust, dated June 15, 1937, executed by
the Company to The Bank of New York (successor trustee to Bank of America,
National Association, formerly Boatmen's Trust Company), as trustee (herein
called the "Trustee"), as amended by indentures supplemental thereto dated May
1, 1941, April 1, 1971, February 1, 1974, July 7, 1980 and February 1, 2000,
between the Company and the Trustee (said mortgage and deed of trust, as so
amended, being herein called the "Amended Indenture"), to which Amended
Indenture and all indentures supplemental thereto reference is hereby made for a
description of the properties mortgaged and pledged, the nature and extent of
the security, the rights of the bearers or registered owners of the Bonds and of
the Trustee in respect thereto, and the terms and conditions upon which the
Bonds are, and are to be, secured. To the extent permitted by, and as provided
in, the Amended Indenture, modifications or alterations of the Amended
Indenture, or of any indenture supplemental thereto, and of the rights and
obligations of the Company and of the holders of the Bonds may be made with the
consent of the Company by an affirmative vote of not less than 60% in amount of
the Bonds entitled to vote then outstanding, at a meeting of Bondholders called
and held as provided in the Amended Indenture, and by an affirmative vote of not
less than 60% in amount of the Bonds of any series entitled to vote then
outstanding and affected by such modification or alteration, in case one or more
but less than all of the series of Bonds then outstanding under the Amended
Indenture are so affected. Additionally, the Company may amend the Amended
Indenture, as supplemented, by an appropriate written consent of not less than
60% in aggregate principal amount of the Bonds outstanding without a meeting of
such Bondholders. No such modification or alteration shall be made which will
affect the terms of payment of the principal of, or interest or premium on, this
Bond, which are unconditional. The Bonds may be issued in series, for various
principal sums, may mature at different times, may bear interest at different
rates and may otherwise vary as in the Amended Indenture provided. This Bond is
one of a series designated as the "First Mortgage Bonds, Senior Notes Series AA"
(herein called the "Bonds of this Series") of the Company, issued under and
secured by the Amended Indenture and described in the indenture (hereinafter
called the "New Supplemental Indenture") dated August 15, 2002, between the
Company and the Trustee, supplemental to the Amended Indenture.

     The Bonds of this Series are not entitled to the benefit of any
improvement, maintenance or analogous fund.

     This Bond is not redeemable except on the date, in the principal amount and
for the redemption price that correspond to the redemption dates for, the
principal amount to be redeemed of, and the redemption price for, the Senior
Notes, and except upon written demand of the Senior Note Trustee following the
occurrence of an event of default under the Senior Note Indenture and the
acceleration of the Senior Notes, as provided in Section 8.01 of the Senior Note
Indenture.

     In case an event of default, as defined in the Amended Indenture, shall
occur, the principal of all the Bonds at any such time outstanding under the
Amended Indenture may be declared or may become due and payable, upon the
conditions and in the manner and with the

<Page>

effect provided in the Amended Indenture. The Amended Indenture provides that
such declaration may in certain events be waived by the holders of a majority in
principal amount of the Bonds outstanding.

     This Bond shall not be assignable or transferable except as permitted or
required by Section 4.04 of the Senior Note Indenture. This Bond is exchangeable
by the registered owner hereof, in person or by duly authorized attorney, on the
books of the Company to be kept for that purpose at the office of the Company in
the City of St. Louis, Missouri, upon surrender and cancellation of this Bond
and on presentation of a duly executed written instrument of transfer, and
thereupon a new Bond or Bonds of the same series, of the same aggregate
principal amount and in authorized denominations will be issued to the
transferee or transferees in exchange herefor, without payment of any charge
other than stamp taxes and other governmental charges incident thereto; and this
Bond with or without others of like series, may in like manner be exchanged for
one or more new Bonds of the same series of other authorized denominations but
of the same aggregate principal amount; all subject to the terms and conditions
set forth in the Amended Indenture.

     As provided in Section 4.11 of the Senior Note Indenture, from and after
the Release Date (as defined in the Senior Note Indenture), the obligations of
the Company with respect to this Bond shall be deemed to be satisfied and
discharged, this Bond shall cease to secure in any manner any Senior Notes
outstanding under the Senior Note Indenture, and, pursuant to Section 4.08 of
the Senior Note Indenture, the Senior Note Trustee shall forthwith deliver this
Bond to the Company for cancellation.

     No recourse shall be had for the payment of the principal of, premium, if
any, on or the interest on, this Bond, or for any claim based hereon or on the
Amended Indenture or any indenture supplemental thereto, against any
incorporator, or against any stockholder, director or officer, past, present or
future, of the Company, or of any predecessor or successor corporation, either
directly or through the Company or any such predecessor or successor
corporation, whether for amounts unpaid on stock subscriptions or by virtue of
any constitution, statute or rule of law, or by the enforcement of any
assessment or penalty or otherwise, all such liability, whether at common law,
in equity, by any constitution, statute or otherwise, of incorporators,
stockholders, directors or officers being released by every owner hereof by the
acceptance of this Bond and as part of the consideration for the issue hereof,
and being likewise released by the terms of the Amended Indenture.<Page>

                                                                     EXHIBIT 4.3

WHEN RECORDED
MAIL TO:

Gerald L. Waters
Union Electric Company
1901 Chouteau Avenue
St. Louis, MO 61303

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

                      Executed in 50 Counterparts, No. 28.

                             SUPPLEMENTAL INDENTURE

                              DATED AUGUST 15, 2002

                             UNION ELECTRIC COMPANY

                                       TO

                              THE BANK OF NEW YORK,
                                   AS TRUSTEE

                                    --------

     (SUPPLEMENTAL TO THE INDENTURE OF MORTGAGE AND DEED OF TRUST DATED
     JUNE 15, 1937, AS AMENDED, EXECUTED BY UNION ELECTRIC COMPANY TO
     THE BANK OF NEW YORK, AS TRUSTEE)

                                    --------

                       First Mortgage Bonds, Senior Notes
                                    Series AA

        This instrument was prepared by Steven R. Sullivan, Vice
        President, General Counsel and Secretary of Union
        Electric Company, 1901 Chouteau Avenue, St. Louis,
        Missouri 63103.

<Page>

     SUPPLEMENTAL INDENTURE, dated the 15th day of August, Two thousand and two
(2002) made by and between UNION ELECTRIC COMPANY, a corporation organized and
existing under the laws of the State of Missouri (hereinafter called the
"Company"), party of the first part, and The Bank of New York (successor trustee
to Bank of America, National Association, formerly Boatmen's Trust Company), a
bank existing under the laws of the State of New York (hereinafter called the
"Trustee"), as Trustee under the Indenture of Mortgage and Deed of Trust dated
June 15, 1937, hereinafter mentioned, party of the second part:

     WHEREAS, the Company has heretofore executed and delivered to the Trustee
its Indenture of Mortgage and Deed of Trust, dated June 15, 1937, as amended May
1, 1941, April 1, 1971, February 1, 1974, July 7, 1980 and February 1, 2000
(said Indenture of Mortgage and Deed of Trust as so amended, being hereinafter
referred to as the "Original Indenture"), to secure the payment of the principal
of and the interest (and premium, if any) on all bonds at any time issued and
outstanding thereunder, and indentures supplemental thereto dated June 15, 1937,
May 1, 1941, March 17, 1942, April 13, 1945, April 27, 1945, October 1, 1945,
April 11, 1947, April 13, 1949, September 13, 1950, December 1, 1950, September
20, 1951, May 1, 1952, March 1, 1954, May 1, 1955, August 31, 1955, April 1,
1956, July 1, 1956, August 1, 1957, February 1, 1958, March 1, 1958, November 5,
1958, March 16, 1959, June 24, 1959, December 11, 1959, August 17, 1960,
September 1, 1960, October 24, 1960, June 30, 1961, July 1, 1961, August 9,
1962, September 30, 1963, November 1, 1963, March 12, 1965, April 1, 1965, April
14, 1966, May 1, 1966, February 17, 1967, March 1, 1967, February 19, 1968,
March 15, 1968, August 21, 1968, April 7, 1969, May 1, 1969, September 12, 1969,
October 1, 1969, March 26, 1970, April 1, 1970, June 12, 1970, January 1, 1971,
April 1, 1971, September 15, 1971, December 3, 1973, February 1, 1974, April 25,
1974, February 3, 1975, March 1, 1975, June 11, 1975, May 12, 1976, August 16,
1976, April 26, 1977, October 15, 1977, November 7, 1977, December 1, 1977,
August 1, 1978, October 12, 1979, November 1, 1979, July 7, 1980, August 1,
1980, August 20, 1980, February 1, 1981, October 8, 1981, August 27, 1982,
September 1, 1982, December 15, 1982, March 1, 1983, June 21, 1984, December 12,
1984, June 11, 1985, March 1, 1986, May 1, 1986, May 1, 1990, December 1, 1991,
December 4, 1991, January 1, 1992, September 30, 1992, October 1, 1992, December
1, 1992, February 1, 1993, February 18, 1993, May 1, 1993, August 1, 1993,
October 1, 1993, January 1, 1994, and February 1, 2000, respectively, have
heretofore been entered into between the Company and the Trustee; and

     WHEREAS, Bonds have heretofore been issued by the Company under the
Original Indenture as follows:

          (1)  $80,000,000 principal amount of First Mortgage and Collateral
     Trust Bonds, 3 3/4% Series due 1962, all of which have been redeemed prior
     to the date of the execution hereof;

          (2)  $90,000,000 principal amount of First Mortgage and Collateral
     Trust Bonds, 3 3/8% Series due 1971, which are described in the
     Supplemental Indenture dated May 1, 1941 (hereinafter called the
     "Supplemental Indenture of May 1, 1941"), all of which have been paid at
     maturity prior to the date of the execution hereof;

          (3)  $13,000,000 principal amount of First Mortgage and Collateral
     Trust Bonds, 2 3/4% Series due 1975 (herein called the "Bonds of 1975
     Series"), which are described in the Supplemental Indenture dated October
     1, 1945 (hereinafter called the

<Page>

     "Supplemental Indenture of October 1, 1945"), all of which have been paid
     at maturity prior to the date of the execution hereof;

          (4)  $25,000,000 principal amount of First Mortgage and Collateral
     Trust Bonds, 2 7/8% Series due 1980 (herein called the "Bonds of 1980
     Series"), which are described in the Supplemental Indenture dated December
     1, 1950 (hereinafter called the "Supplemental Indenture of December 1,
     1950"), all of which have been paid at maturity prior to the date of the
     execution hereof;

          (5)  $30,000,000 principal amount of First Mortgage and Collateral
     Trust Bonds, 3 1/4% Series due 1982 (herein called the "Bonds of 1982
     Series"), which are described in the Supplemental Indenture dated May 1,
     1952 (hereinafter called the "Supplemental Indenture of May 1, 1952"), all
     of which have been paid at maturity prior to the date of the execution
     hereof;

          (6)  $40,000,000 principal amount of First Mortgage Bonds, 3 3/4%
     Series due 1986 (herein called the "Bonds of 1986 Series"), which are
     described in the Supplemental Indenture dated July 1, 1956 (hereinafter
     called the "Supplemental Indenture of July 1, 1956"), all of which have
     been paid at maturity prior to the date of the execution hereof;

          (7)  $35,000,000 principal amount of First Mortgage Bonds, 4 3/8%
     Series due 1988 (herein called the "Bonds of 1988 Series"), which are
     described in the Supplemental Indenture dated March 1, 1958 (hereinafter
     called the "Supplemental Indenture of March 1, 1958"), all of which have
     been paid at maturity prior to the date of the execution hereof;

          (8)  $50,000,000 principal amount of First Mortgage Bonds, 4 3/4%
     Series due 1990 (herein called the "Bonds of 1990 Series"), which are
     described in the Supplemental Indenture dated September 1, 1960
     (hereinafter called the "Supplemental Indenture of September 1, 1960"), all
     of which have been paid at maturity prior to the date of the execution
     hereof;

          (9)  $30,000,000 principal amount of First Mortgage Bonds, 4 3/4%
     Series due 1991 (herein called the "Bonds of 1991 Series"), which are
     described in the Supplemental Indenture dated July 1, 1961 (hereinafter
     called the "Supplemental Indenture of July 1, 1961"), all of which have
     been paid at maturity prior to the date of the execution hereof;

          (10) $30,000,000 principal amount of First Mortgage Bonds, 4 1/2%
     Series due 1993 (herein called the "Bonds of 1993 Series"), which are
     described in the Supplemental Indenture dated November 1, 1963 (hereinafter
     called the "Supplemental Indenture of November 1, 1963"), all of which have
     been redeemed prior to the date of the execution hereof;

          (11) $35,000,000 principal amount of First Mortgage Bonds, 4 1/2%
     Series due 1995 (herein called the "Bonds of 1995 Series"), which are
     described in the Supplemental Indenture dated April 1, 1965 (hereinafter
     called the "Supplemental Indenture of April 1, 1965"), all of which have
     been paid at maturity prior to the date of the execution hereof;

          (12) $30,000,000 principal amount of First Mortgage Bonds, 5 1/2%
     Series due 1996 (herein called the "Bonds of 1996 Series"), which are
     described in the Supplemental

                                        2
<Page>

     Indenture dated May 1, 1966 (hereinafter called the "Supplemental Indenture
     of May 1, 1966"), all of which have been paid at maturity prior to the date
     of the execution hereof;

          (13) $40,000,000 principal amount of First Mortgage Bonds, 5 1/2%
     Series due 1997 (herein called the "Bonds of 1997 Series"), which are
     described in the Supplemental Indenture dated March 1, 1967 (hereinafter
     called the "Supplemental Indenture of March 1, 1967"), all of which have
     been paid at maturity prior to the date of the execution hereof;

          (14) $50,000,000 principal amount of First Mortgage Bonds, 7% Series
     due 1998 (herein called the "Bonds of 1998 Series"), which are described in
     the Supplemental Indenture dated March 15, 1968 (hereinafter called the
     "Supplemental Indenture of March 15, 1968"), all of which have been
     redeemed prior to the date of the execution hereof;

          (15) $35,000,000 principal amount of First Mortgage Bonds, 7 3/8%
     Series due 1999 (herein called the "Bonds of May 1999 Series"), which are
     described in the Supplemental Indenture dated May 1, 1969 (hereinafter
     called the "Supplemental Indenture of May 1, 1969"), all of which have been
     redeemed prior to the date of the execution hereof;

          (16) $40,000,000 principal amount of First Mortgage Bonds, 8 1/4%
     Series due 1999 (herein called the "Bonds of October 1999 Series"), which
     are described in the Supplemental Indenture dated October 1, 1969
     (hereinafter called the "Supplemental Indenture of October 1, 1969"), all
     of which have been redeemed prior to the date of the execution hereof;

          (17) $100,000,000 principal amount of First Mortgage Bonds, 9.95%
     Series due 1999 (herein called the "Bonds of November 1999 Series"), which
     are described in the Supplemental Indenture dated November 1, 1979
     (hereinafter called the "Supplemental Indenture of November 1, 1979"), all
     of which have been redeemed prior to the date of the execution hereof;

          (18) $60,000,000 principal amount of First Mortgage Bonds, 9% Series
     due 2000 (herein called the "Bonds of 2000 Series"), which are described in
     the Supplemental Indenture dated April 1, 1970 (hereinafter called the
     "Supplemental Indenture of April 1, 1970"), all of which have been redeemed
     prior to the date of the execution hereof;

          (19) $50,000,000 principal amount of First Mortgage Bonds, 7 7/8%
     Series due 2001 (herein called the "Bonds of January 2001 Series"), which
     are described in the Supplemental Indenture dated January 1, 1971
     (hereinafter called the "Supplemental Indenture of January 1, 1971"), all
     of which have been redeemed prior to the date of the execution hereof;

          (20) $50,000,000 principal amount of First Mortgage Bonds, 7 5/8%
     Series due 2001 (herein called the "Bonds of April 2001 Series"), which are
     described in the Supplemental Indenture dated April 1, 1971 (hereinafter
     called the "Supplemental Indenture of April 1, 1971"), all of which have
     been redeemed prior to the date of the execution hereof;

                                        3
<Page>

          (21) $60,000,000 principal amount of First Mortgage Bonds, 8 1/8%
     Series due 2001 (herein called the "Bonds of October 2001 Series"), which
     are described in the Supplemental Indenture dated September 15, 1971
     (hereinafter called the "Supplemental Indenture of September 15, 1971"),
     all of which have been redeemed prior to the date of the execution hereof;

          (22) $70,000,000 principal amount of First Mortgage Bonds, 8 3/8%
     Series due 2004 (herein called the "Bonds of 2004 Series"), which are
     described in the Supplemental Indenture dated February 1, 1974 (hereinafter
     called the "Supplemental Indenture of February 1, 1974"), all of which have
     been redeemed prior to the date of the execution hereof;

          (23) $70,000,000 principal amount of First Mortgage Bonds, 10 1/2%
     Series due 2005 (herein called the "Bonds of 2005 Series"), which are
     described in the Supplemental Indenture dated March 1, 1975 (hereinafter
     called the "Supplemental Indenture of March 1, 1975"), all of which have
     been redeemed prior to the date of the execution hereof;

          (24) $70,000,000 principal amount of First Mortgage Bonds, 8 7/8%
     Series due 2006 (herein called the "Bonds of 2006 Series"), which are
     described in the Supplemental Indenture dated August 16, 1976 (hereinafter
     called the "Supplemental Indenture of August 16, 1976"), all of which have
     been redeemed prior to the date of the execution hereof;

          (25) $27,085,000 principal amount of First Mortgage Bonds, 5.80%
     Environmental Improvement Series 1977, which are described in the
     Supplemental Indenture dated October 15, 1977 (hereinafter called the
     "Supplemental Indenture of October 15, 1977"), all of which have been
     redeemed prior to the date of the execution hereof;

          (26) $60,000,000 principal amount of First Mortgage Bonds, 8 5/8%
     Series due 2007 (herein called the "Bonds of 2007 Series"), which are
     described in the Supplemental Indenture dated December 1, 1977 (hereinafter
     called the "Supplemental Indenture of December 1, 1977"), all of which have
     been redeemed prior to the date of the execution hereof;

          (27) $55,000,000 principal amount of First Mortgage Bonds, 9.35%
     Series due 2008 (herein called the "Bonds of 2008 Series"), which are
     described in the Supplemental Indenture dated August 1, 1978 (hereinafter
     called the "Supplemental Indenture of August 1, 1978"), all of which have
     been redeemed prior to the date of the execution hereof;

          (28) $60,000,000 principal amount of First Mortgage Bonds,
     Environmental Improvement Series 1980, which are described in the
     Supplemental Indenture dated August 1, 1980 (hereinafter called the
     "Supplemental Indenture of August 1, 1980"), all of which have been
     redeemed prior to the date of the execution hereof;

          (29) $150,000,000 principal amount of First Mortgage Bonds, 15 3/8%
     Series due 1991 (herein called the "Bonds of February 1991 Series"), which
     are described in the Supplemental Indenture dated February 1, 1981
     (hereinafter called the "Supplemental

                                        4
<Page>

     Indenture of February 1, 1981"), all of which have been redeemed prior to
     the date of the execution hereof;

          (30) $125,000,000 principal amount of First Mortgage Bonds, 15% Series
     due 1992 (herein called the "Bonds of 1992 Series"), which are described in
     the Supplemental Indenture dated September 1, 1982 (hereinafter called the
     "Supplemental Indenture of September 1, 1982"), all of which have been
     redeemed prior to the date of the execution hereof;

          (31) $100,000,000 principal amount of First Mortgage Bonds, 13% Series
     due 2013 (herein called the "Bonds of 2013 Series"), which are described in
     the Supplemental Indenture dated March 1, 1983 (hereinafter called the
     "Supplemental Indenture of March 1, 1983"), all of which have been redeemed
     prior to the date of the execution hereof;

          (32) $100,000,000 principal amount of First Mortgage Bonds, 9 3/8%
     Series due 2016 (herein called the "Bonds of 2016 Series"), which are
     described in the Supplemental Indenture dated March 1, 1986 (hereinafter
     called the "Supplemental Indenture of March 1, 1986"), all of which have
     been redeemed prior to the date of the execution hereof;

          (33) $100,000,000 principal amount of First Mortgage Bonds, 8 7/8%
     Series due 1996 (herein called the "Bonds of 1996 Series"), which are
     described in the Supplemental Indenture dated May 1, 1986 (hereinafter
     called the "Supplemental Indenture of May 1, 1986"), all of which have been
     redeemed prior to the date of the execution hereof;

          (34) $60,000,000 principal amount of First Mortgage Bonds,
     Environmental Improvement Series 1990A, which are described in the
     Supplemental Indenture dated May 1, 1990 (hereinafter called the
     "Supplemental Indenture of May 1, 1990"), all of which have been redeemed
     prior to the date of the execution hereof;

          (35) $125,000,000 principal amount of First Mortgage Bonds, 8 3/4%
     Series due 2021 (herein called the "Bonds of 2021 Series"), which are
     described in the Supplemental Indenture dated December 1, 1991 (hereinafter
     called the "Supplemental Indenture of December 1, 1991"), all of which are
     outstanding at the date of the execution hereof;

          (36) $75,000,000 principal amount of First Mortgage Bonds, 8.33%
     Series due 2002 (herein called the "Bonds of 2002 Series"), which are
     described in the Supplemental Indenture dated December 4, 1991 (hereinafter
     called the "Supplemental Indenture of December 4, 1991"), all of which are
     outstanding at the date of the execution hereof;

          (37) $100,000,000 principal amount of First Mortgage Bonds, 7.65%
     Series due 2003 (herein called the "Bonds of 2003 Series"), which are
     described in the Supplemental Indenture dated January 1, 1992 (hereinafter
     called the "Supplemental Indenture of January 1, 1992"), all of which are
     outstanding at the date of the execution hereof;

          (38) $204,000,000 aggregate principal amount of First Mortgage Bonds,
     consisting of $100,000,000 principal amount of 6 3/4% Series due 1999 and

                                        5
<Page>

     $104,000,000 principal amount of 8 1/4% Series due 2022 (herein called the
     "Bonds of 1999 Series" and "Bonds of 2022 Series", respectively), which are
     described in the Supplemental Indenture dated October 1, 1992 (hereinafter
     called the "Supplemental Indenture of October 1, 1992"), of which the Bonds
     of 1999 Series have been paid at maturity prior to the date of execution
     hereof and the Bonds of 2022 Series are outstanding at the date of the
     execution hereof;

          (39) $170,000,000 aggregate principal amount of First Mortgage Bonds,
     consisting of $85,000,000 principal amount of 7 3/8% Series due 2004 and
     $85,000,000 principal amount of 8% Series due 2022 (herein called the
     "Bonds of December 2004 Series" and "Bonds of December 2022 Series",
     respectively, which are described in the Supplemental Indenture dated
     December 1, 1992, (hereinafter called the "Supplemental Indenture of
     December 1, 1992), all of which are outstanding at the date of the
     execution hereof;

          (40) $188,000,000 principal amount of First Mortgage Bonds, 6 7/8%
     Series due 2004 (herein called the "Bonds of August 2004 Series"), which
     are described in the Supplemental Indenture dated February 1, 1993
     (hereinafter called the "Supplemental Indenture of February 1, 1993"), all
     of which are outstanding at the date of the execution hereof;

          (41) $148,000,000 principal amount of First Mortgage Bonds, 6 3/4%
     Series due 2008 (herein called the "Bonds of May 2008 Series"), which are
     described in the Supplemental Indenture dated May 1, 1993 (hereinafter
     called the "Supplemental Indenture of May 1, 1993"), all of which are
     outstanding at the date of the execution hereof;

          (42) $75,000,000 principal amount of First Mortgage Bonds, 7.15%
     Series due 2023 (herein called the "Bonds of 2023 Series"), which are
     described in the Supplemental Indenture dated August 1, 1993 (hereinafter
     called the "Supplemental Indenture of August 1, 1993"), all of which are
     outstanding at the date of the execution hereof;

          (43) $44,000,000 principal amount of First Mortgage Bonds,
     Environmental Improvement Series 1993 (herein called the "Bonds of 2028
     Series"), which are described in the Supplemental Indenture dated October
     1, 1993 (hereinafter called the "Supplemental Indenture of October 1,
     1993"), all of which are outstanding at the date of the execution hereof;
     and

          (44) $100,000,000 principal amount of First Mortgage Bonds, 7% Series
     due 2024 (herein called the "Bonds of 2024 Series"), which are described in
     the Supplemental Indenture dated January 1, 1994 (hereinafter called the
     "Supplemental Indenture of January 1, 1994"), all of which are outstanding
     at the date of the execution hereof;

and

     WHEREAS, the Company on August 31, 1955 acquired all of the properties of
Union Electric Power Company, the Subsidiary as defined in Article I of the
Original Indenture, upon the dissolution of the Subsidiary; the Company, by
Supplemental Indenture dated August 31, 1955, conveyed all of the properties so
acquired (other than property of the character defined as excepted property in
the granting clauses of the Original Indenture) to the Trustee upon the terms

                                        6
<Page>

and trusts in the Original Indenture and the indentures supplemental thereto set
forth for the equal and proportionate benefit and security of all present and
future holders of the Bonds and coupons issued and to be issued thereunder, all
the shares of stock of the Subsidiary were released from the lien of the
Original Indenture; and the Company became entitled to change the general
designation of the Bonds so as to omit the words "and Collateral Trust"; and

     WHEREAS, the Articles of Incorporation of the Company were duly amended on
April 23, 1956, to change its corporate name from "Union Electric Company of
Missouri" to "Union Electric Company"; and

     WHEREAS, the Articles of Agreement of the Trustee were duly amended
effective on January 4, 1982 to change its corporate name from "St. Louis Union
Trust Company" to "Centerre Trust Company of St. Louis", and further amended on
December 9, 1988, to change its corporate name from "Centerre Trust Company of
St. Louis" to "Boatmen's Trust Company"; and

     WHEREAS, that on March 13, 1998, Boatmen's Trust Company merged into
NationsBank, National Association and effective July 5, 1999, changed its name
to Bank of America, National Association; and

     WHEREAS, that on February 1, 2000, The Bank of New York, as transferee of
the corporate trust business of Bank of America, National Association (formerly
known as Boatmen's Trust Company), Trustee under the Original Indenture, became
successor Trustee under the Original Indenture; and

     WHEREAS, the Company is entitled at this time to have authenticated and
delivered additional Bonds on the basis of "refundable bonds" upon compliance
with and pursuant to the provisions of Section 6 of Article III of the Original
Indenture; and

     WHEREAS, the Company has entered into an Indenture dated as of August 15,
2002 (the "Senior Note Indenture") with The Bank of New York, as trustee (the
"Senior Note Trustee") providing for the issuance from time to time of senior
notes thereunder; and

     WHEREAS, the Company desires by this Supplemental Indenture to provide for
the creation of, and the issuance to the Senior Note Trustee of, a new series of
Bonds under the Original Indenture as security for $173,000,000 aggregate
principal amount of the Company's 5.25% Senior Secured Notes due 2012 (the
"Senior Notes") to be issued under the Senior Note Indenture, to have the
designation provided in Article I, Section 1 hereof (herein called the "New
Bonds"), and the Original Indenture provides that certain terms and provisions,
as determined by the Board of Directors of the Company, of the Bonds of any
particular series may be expressed in and provided by the execution of an
appropriate supplemental indenture; and

     WHEREAS, the Company also desires by this Supplemental Indenture to amend
the provisions of Article XV of the Original Indenture to establish new
procedures concerning amendments thereof, as set forth in Article VI hereof; and

     WHEREAS, the Original Indenture provides that the Company and the Trustee
may enter into indentures supplemental to the Original Indenture specifically to
convey, transfer and assign to the Trustee and to subject to the lien of the
Original Indenture additional properties acquired by the Company; and

                                        7
<Page>

     WHEREAS, the Company, in the exercise of the powers and authority conferred
upon and reserved to it under the provisions of the Original Indenture and
pursuant to appropriate resolutions of the Board of Directors, has duly resolved
and determined to make, execute and deliver to the Trustee a Supplemental
Indenture in the form hereof for the purposes herein provided; and

     WHEREAS, all conditions and requirements necessary to make this
Supplemental Indenture a valid, binding and legal instrument have been done,
performed and fulfilled and the execution and delivery hereof have been in all
respects duly authorized;

     NOW, THEREFORE, THIS INDENTURE WITNESSETH:

     That, in consideration of the premises and of the mutual covenants herein
contained and of the acceptance of this trust by the Trustee and of the sum of
One Dollar duly paid by the Trustee to the Company at or before the time of the
execution of this Supplemental Indenture, and of other valuable considerations,
the receipt whereof is hereby acknowledged, and in order further to secure the
payment of the principal of and interest (and premium, if any) on all Bonds at
any time issued and outstanding under the Original Indenture, according to their
tenor and effect, and to secure the Senior Notes, the Company has executed and
delivered this Supplemental Indenture and has granted, bargained, sold,
warranted, aliened, remised, released, conveyed, assigned, transferred,
mortgaged, pledged, set over and confirmed and by these presents does grant,
bargain, sell, warrant, alien, remise, release, convey, assign, transfer,
mortgage, pledge, set over and confirm unto The Bank of New York, as Trustee,
and to its successors in trust under the Original Indenture forever, all and
singular the following described properties (in addition to all other properties
heretofore subjected to the lien of the Original Indenture and not heretofore
released from the lien thereof) - that is to say:

                                        8
<Page>

                                     FIRST.

     ALL power houses, plants, buildings and other structures, dams, dam sites,
substations, heating plants, gas works, holders and tanks, together with all and
singular the electric, heating, gas and mechanical appliances appurtenant
thereto of every nature whatsoever, now owned by the Company, including all and
singular the machinery, engines, boilers, furnaces, generators, dynamos,
turbines and motors, and all and every character of mechanical appliance for
generating or producing electricity, steam, gas and other agencies for light,
heat, cold, or power or other purposes, and all transmission and distribution
systems used for the transmission and distribution of electricity, steam, gas
and other agencies for light, heat, cold or power or any other purpose
whatsoever, whether underground or overhead, surface or otherwise, now owned by
the Company, including all poles, towers, posts, wires, cables, conduits,
manholes, mains, pipes, tubes, drains, furnaces, switchboards, transformers,
conductors, insulators, supports, meters, lamps, fuses, junction boxes,
regulator stations, and other electric, steam and gas fixtures and apparatus;
all of the aforementioned property being located in the City of St. Louis, the
counties of Adair, Audrain, Benton, Bollinger, Boone, Butler, Caldwell,
Callaway, Camden, Cape Girardeau, Clark, Clay, Clinton, Cole, Cooper, Crawford,
Daviess, Dunklin, Franklin, Gasconade, Howard, Iron, Jefferson, Knox, Lewis,
Lincoln, Livingston, Macon, Madison, Maries, Marion, Miller, Mississippi,
Moniteau, Montgomery, Morgan, New Madrid, Osage, Pemiscot, Perry, Pettis,
Phelps, Pike, Pulaski, Ralls, Randolph, Ray, Reynolds, Ripley, St. Charles, St.
Francois, Ste. Genevieve, St. Louis, Saline, Schuyler, Scott, Stoddard, Warren,
Washington, and Wayne, Missouri, the counties of Adams, Alexander, Calhoun,
Franklin, Hancock, Henderson, Jackson, Jersey, Macoupin, Madison, Massac,
Monroe, Perry, Pike, Pulaski, St. Clair, Union, and Washington, Illinois, and
the counties of Des Moines, Henry, Johnson, Lee, and Washington, Iowa, upon real
estate owned by the Company, or occupied by it under rights to so occupy, which
real estate is described in the Indenture of Mortgage and Deed of Trust dated
June 15, 1937, in the Supplemental Indentures dated May 1, 1941, March 17, 1942,
April 13, 1945, April 27, 1945, October 1, 1945, April 11, 1947, April 13, 1949,
September 13, 1950, December 1, 1950, September 20, 1951, May 1, 1952, March 1,
1954, May 1, 1955, August 31, 1955, April 1, 1956, July 1, 1956, August 1, 1957,
February 1, 1958, March 1, 1958, November 5, 1958, March 16, 1959, June 24,
1959, December 11, 1959, August 17, 1960, September 1, 1960, October 24, 1960,
June 30, 1961, July 1, 1961, August 9, 1962, September 30, 1963, November 1,
1963, March 12, 1965, April 1, 1965, April 14, 1966, May 1, 1966, February 17,
1967, March 1, 1967, February 19, 1968, March 15, 1968, August 21, 1968, April
7, 1969, May 1, 1969, September 12, 1969, October 1, 1969, March 26, 1970, April
1, 1970, June 12, 1970, January 1, 1971, April 1, 1971, September 15, 1971,
December 3, 1973, February 1, 1974, April 25, 1974, February 3, 1975, March 1,
1975, June 11, 1975, May 12, 1976, August 16, 1976, April 26, 1977, October 15,
1977, November 7, 1977, December 1, 1977, August 1, 1978, October 12, 1979,
November 1, 1979, July 7, 1980, August 1, 1980, August 20, 1980, February 1,
1981, October 8, 1981, August 27, 1982, September 1, 1982, December 15, 1982,
March 1, 1983, June 21, 1984, December 12, 1984, June 11, 1985, March 1, 1986,
May 1, 1986, May 1, 1990, December 1, 1991, December 4, 1991, January 1, 1992,
September 30, 1992, October 1, 1992, December 1, 1992, February 1, 1993,
February 18, 1993, May 1, 1993, August 1, 1993, October 1, 1993, January 1,
1994, February 1, 2000 and in this Supplemental Indenture, or attached to or
connected with such real estate or transmission or distribution systems of the
Company leading from or into such real estate.

                                        9
<Page>

                                     SECOND.

     ALSO, (except as in the Original Indenture expressly excepted) all
franchises and all permits, ordinances, easements, privileges, immunities and
licenses, all rights to construct, maintain and operate overhead, surface and
underground systems for the distribution and transmission of electricity, steam,
gas or other agencies for the supply to itself or others of light, heat, cold or
power, all rights-of-way, all waters, water rights and flowage rights and all
grants and consents, now owned or, subject to the provisions of Article XII of
the Original Indenture, which it may hereafter acquire.

     ALSO, (except as in the Original Indenture expressly excepted) all
inventions, patent rights and licenses of every kind now owned by the Company
or, subject to the provisions of Article XII of the Original Indenture, which it
may hereafter acquire.

                                     THIRD.

     ALSO, subject to the provisions of Article XII of the Original Indenture,
all other property, real, personal and mixed (except as therein or herein
expressly excepted) of every nature and kind and wheresoever situated now or
hereafter possessed by or belonging to the Company, or to which it is now, or
may at any time hereafter be, in any manner entitled at law or in equity.

     TO HAVE AND TO HOLD all said properties, real, personal and mixed,
mortgaged, pledged and conveyed by the Company as aforesaid, or intended so to
be, unto the Trustee and its successors and assigns forever;

     SUBJECT, HOWEVER, to the exceptions and reservations and matters
hereinabove recited, to existing leases, to existing liens upon rights of way
for transmission or distribution line purposes, as defined in Article I of the
Original Indenture, and any extensions thereof, and subject to existing
easements for streets, alleys, highways, rights-of-way and railroad purposes
over, upon and across certain of the property hereinbefore described, and
subject also to all the terms, conditions, agreements, covenants, exceptions and
reservations expressed or provided in the deeds or other instruments
respectively under and by virtue of which the Company acquired the properties
hereinabove described, and to undetermined liens and charges, if any, incidental
to construction or other existing permitted liens as defined in Article I of the
Original Indenture;

     IN TRUST, NEVERTHELESS, upon the terms and trusts in the Original Indenture
and the indentures supplemental thereto, including this Supplemental Indenture,
set forth, for the equal and proportionate benefit and security of all present
and future holders of the Bonds and coupons issued and to be issued thereunder,
or any of them, without preference of any of said Bonds and coupons of any
particular series over the Bonds and coupons of any other series, by reason of
priority in the time of the issue, sale or negotiation thereof, or by reason of
the purpose of issue or otherwise howsoever, except as otherwise provided in
Section 2 of Article IV of the Original Indenture.

     AND IT IS HEREBY COVENANTED, DECLARED AND AGREED, by and between the
parties hereto, for the benefit of those who shall hold the Bonds and coupons,
or any of them to be issued under the Original Indenture, as follows:

                                       10
<Page>

                                    ARTICLE I

                          DESCRIPTION OF THE NEW BONDS

     Section 1. There is hereby created a new series of Bonds to be executed,
authenticated and delivered under and secured by the Original Indenture which
shall, subject to the provisions of Section 1 of Article II of the Original
Indenture, be designated as "First Mortgage Bonds, Senior Notes Series AA" (the
"New Bonds") of the Company. The New Bonds shall be executed, authenticated and
delivered in accordance with the provisions of, and shall in all respects be
subject to all of the terms, conditions and covenants of, the Original Indenture
and shall be issued to, and registered in the name of, the Senior Note Trustee
under the Senior Note Indenture to secure any and all obligations of the Company
under the Senior Notes and any other series of senior notes from time to time
outstanding under the Senior Note Indenture.

     The New Bonds shall mature on September 1, 2012, and shall bear interest at
the rate per annum set forth in the form of the New Bond contained in Section 3
of this Article I, payable semi-annually on the 1st day of March and the 1st day
of September in each year, commencing on March 1, 2003, and at maturity. The New
Bonds shall be payable as to principal, premium, if any, and interest in any
coin or currency of the United States of America which at the time of payment is
legal tender for public and private debts, and shall be payable, in immediately
available funds, at the office of the Senior Note Trustee.

     Section 2. The New Bonds shall not be assignable or transferable except as
permitted or required by Section 4.04 of the Senior Note Indenture. Any such
transfer shall be effected at the principal office or place of business of the
Trustee under the Original Indenture. The New Bonds are exchangeable for the New
Bonds of other denominations, as in the Original Indenture provided, except that
payment of a service charge therefor will not be required by the Company.

     Notwithstanding the provisions of Section 6 of Article II of the Original
Indenture, the New Bonds shall be dated the date of authentication and shall
bear interest from the interest payment date to which interest on the New Bonds
has been paid next preceding the date thereof, unless such date is an interest
payment date to which interest has been paid, in which case they shall bear
interest from the date thereof, or unless the date thereof is prior to March 1,
2003, in which case they shall bear interest from August 22, 2002; provided,
however, that, subject to the provisions of this Section with respect to failure
by the Company to pay any interest on an interest payment date, the holder of
any New Bond dated after a record date (as hereinafter defined) for the payment
of interest and prior to the date of payment of such interest shall not be
entitled to payment of such interest and shall have no claim against the Company
with respect thereto.

     The person in whose name any New Bond is registered at the close of
business on any record date with respect to any interest payment date shall be
entitled to receive the interest payable on such interest payment date
notwithstanding the cancellation of such Bond upon any transfer or exchange
thereof subsequent to the record date and prior to such interest payment date,
except if and to the extent the Company shall default in the payment of the
interest due on such interest payment date, in which case such defaulted
interest shall be paid to the person in whose name such Bond is registered on
the date of payment of such defaulted interest or on a subsequent record date
for such payment if one shall have been established as hereinafter

                                       11
<Page>

provided. A subsequent record date may be established by the Company by notice
mailed to the holders of the New Bonds not less than ten days preceding such
record date, which record date shall be not more than thirty days prior to the
subsequent interest payment date. The term "record date" as used in this Section
with respect to any regular interest payment date shall mean the February 15 or
August 15, as the case may be, next preceding such interest payment date, or, if
such February 15 or August 15 shall be a legal holiday in the State of New York
or in the State of Missouri or a day on which banking institutions in the
Borough of Manhattan, The City of New York, or the City of St. Louis, Missouri,
are authorized by law to close, the next preceding day which shall not be a
legal holiday or a day on which such institutions are so authorized to close.

     Upon any payment of the principal of, premium, if any, and interest on, all
or any portion of the Senior Notes, whether at maturity or prior to maturity by
redemption or otherwise or upon provision for the payment thereof having been
made in accordance with Section 5.01(a) of the Senior Note Indenture, the New
Bonds in a principal amount equal to the principal amount of such Senior Notes
and having both a corresponding maturity date and interest rate shall, to the
extent of such payment of principal, premium, if any, and interest, be deemed
paid and the obligation of the Company thereunder to make such payment shall be
discharged to such extent and, in the case of the payment of principal (and
premium, if any), such New Bonds shall be surrendered to the Company for
cancellation as provided in Section 4.08 of the Senior Note Indenture. The
Trustee may at any time and all times conclusively assume that the obligation of
the Company to make payments with respect to the principal of and premium, if
any, and interest on the Senior Notes, so far as such payments at the time have
become due, has been fully satisfied and discharged pursuant to the foregoing
sentence unless and until the Trustee shall have received a written notice from
the Senior Note Trustee signed by one of its officers stating (i) the timely
payment of principal, or premium, if any, or interest on, the Senior Notes has
not been made, (ii) that the Company is in arrears as to the payments required
to be made by it to the Senior Note Trustee pursuant to the Senior Note
Indenture, and (iii) the amount of the arrearage.

     Section 3. The New Bonds and the Trustee's certificate on the New Bonds
shall be substantially in the following forms respectively:

                                       12
<Page>

                           [FORM OF FACE OF NEW BOND]

No.____                                                                $________
                               III. C. C. No. 6226

            NOTWITHSTANDING ANY PROVISIONS HEREOF OR IN THE ORIGINAL
         INDENTURE THIS BOND IS NOT ASSIGNABLE OR TRANSFERABLE EXCEPT AS
         PERMITTED OR REQUIRED BY SECTION 4.04 OF THE INDENTURE DATED AS
         OF AUGUST 15, 2002, BETWEEN UNION ELECTRIC COMPANY AND THE BANK
                            OF NEW YORK, AS TRUSTEE.

                             UNION ELECTRIC COMPANY
             (Incorporated under the laws of the State of Missouri)
                  First Mortgage Bonds, Senior Notes Series AA

     UNION ELECTRIC COMPANY, a corporation organized and existing under the laws
of the State of Missouri (hereinafter called the "Company", which term shall
include any successor corporation as defined in the Amended Indenture referred
to on the reverse hereof), for value received, hereby promises to pay to The
Bank of New York, as trustee under the Senior Note Indenture hereinafter
referred to, or registered assigns, the sum of _________________________________
Dollars, on the 1st day of September, 2012 in any coin or currency of the United
States of America which at the time of payment is legal tender for public and
private debts, and to pay interest thereon, in like coin or currency, at the
rate of FIVE AND ONE QUARTER per centum (5.25%) per annum, payable
semi-annually, on March 1 and September 1 in each year until maturity,
commencing March 1, 2003, and at maturity or, if the Company shall default in
the payment of the principal hereof, until the Company's obligation with respect
to the payment of such principal shall be discharged as provided in the Amended
Indenture referred to on the reverse hereof. Such interest shall be payable from
the March 1 or September 1, as the case may be, next preceding the date hereof
to which interest has not been paid, unless the date hereof is a March 1 or
September 1 to which interest has been paid, in which case from the date hereof,
or unless the date hereof is prior to the first payment of interest, in which
case from August 22, 2002. The interest so payable will be paid to the person in
whose name this Bond, or the Bond in exchange or substitution for which this
Bond shall have been issued, shall have been registered at the close of business
on the February 15 or August 15, as the case may be, next preceding the date of
payment, subject to certain exceptions set forth in the Amended Indenture. The
principal of, and interest and premium, if any, on, this Bond are payable, in
immediately available funds, at the office of the Senior Note Trustee
hereinafter referred to.

     Under an Indenture dated as of August 15, 2002 (the "Senior Note
Indenture") between the Company and The Bank of New York, as trustee (the
"Senior Note Trustee"), the Company will issue, concurrently with the issuance
of this Bond, an issue of notes under the Senior Note Indenture entitled "5.25%
Senior Secured Notes due 2012" (the "Senior Notes"). Pursuant to Article IV of
the Senior Note Indenture, this Bond is issued to the Senior Note Trustee to
secure any and all obligations of the Company under the Senior Notes and any
other series of senior notes from time to time outstanding under the Senior Note
Indenture. Payment of principal of, or premium, if any, or interest on, the
Senior Notes shall constitute payments on this Bond as

                                       13
<Page>

further provided herein and in the Supplemental Indenture dated August 15, 2002
pursuant to which this Bond has been issued (the "Supplemental Indenture").

     Upon any payment of the principal of, premium, if any, and interest on, all
or any portion of the Senior Notes, whether at maturity or prior to maturity by
redemption or otherwise or upon provision for the payment thereof having been
made in accordance with Section 5.01(a) of the Senior Note Indenture, a
principal amount of this Bond equal to the principal amount of such Senior Notes
and having both a corresponding maturity date and interest rate shall, to the
extent of such payment of principal, premium, if any, and interest, be deemed
paid and the obligation of the Company thereunder to make such payment shall be
discharged to such extent and, in the case of the payment of principal (and
premium, if any), such bonds shall be surrendered to the Company for
cancellation as provided in Section 4.08 of the Senior Note Indenture. The
Trustee (as hereinafter defined) may at anytime and all times conclusively
assume that the obligation of the Company to make payments with respect to the
principal of and premium, if any, and interest on, the Senior Notes, so far as
such payments at the time have become due, has been fully satisfied and
discharged pursuant to the foregoing sentence unless and until the Trustee shall
have received a written notice from the Senior Note Trustee signed by one of its
officers stating (i) that timely payment of principal, or premium or interest
on, the Senior Notes has not been made, (ii) that the Company is in arrears as
to the payments required to be made by it to the Senior Note Trustee pursuant to
the Senior Note Indenture, and (iii) the amount of the arrearage.

     For purposes of Section 4.09 of the Senior Note Indenture, this Bond shall
be deemed to be the "Related Series of Senior Note First Mortgage Bonds" in
respect of the Senior Notes.

     This Bond shall not be entitled to any benefit under the Amended Indenture
or any indenture supplemental thereto, or become valid or obligatory for any
purpose, until The Bank of New York, the Trustee under the Amended Indenture, or
a successor trustee thereto under the Amended Indenture, or an agent therefor,
shall have signed the form of certificate endorsed hereon.

     The provisions of this Bond are continued on the reverse hereof and such
continued provisions shall for all purposes have the same effect as though fully
set forth at this place.

     IN WITNESS WHEREOF, Union Electric Company has caused this Bond to be
signed in its name by its Chairman of the Board or President or a Vice President
by manual signature or a facsimile thereof, and its corporate seal (or a
facsimile thereof) to be hereto affixed and attested by its Secretary or an
Assistant Secretary by manual signature or a facsimile thereof.

     Dated,

                                         UNION ELECTRIC COMPANY,

                                         By
                                           ------------------------
                                               Vice President

[CORPORATE SEAL]

Attest:
------------------------------------
Secretary

                                       14
<Page>

                         [FORM OF TRUSTEE'S CERTIFICATE]

     This Bond is one of the Bonds, of the series designated therein, described
in the within-mentioned Amended Indenture and Supplemental Indenture of August
15, 2002.

                                         THE BANK OF NEW YORK, as
                                         TRUSTEE

                                         By
                                           ------------------------------
                                               Authorized Officer

                          [FORM OF REVERSE OF NEW BOND]

     This Bond is one of a duly authorized issue of Bonds of the Company (herein
called the "Bonds"), in unlimited aggregate principal amount, of the series
hereinafter specified, all issued and to be issued under and equally secured by
the indenture of mortgage and deed of trust, dated June 15, 1937, executed by
the Company to The Bank of New York (successor trustee to Bank of America,
National Association, formerly Boatmen's Trust Company), as trustee (herein
called the "Trustee"), as amended by indentures supplemental thereto dated May
1, 1941, April 1, 1971, February 1, 1974, July 7, 1980 and February 1, 2000,
between the Company and the Trustee (said mortgage and deed of trust, as so
amended, being herein called the "Amended Indenture"), to which Amended
Indenture and all indentures supplemental thereto reference is hereby made for a
description of the properties mortgaged and pledged, the nature and extent of
the security, the rights of the bearers or registered owners of the Bonds and of
the Trustee in respect thereto, and the terms and conditions upon which the
Bonds are, and are to be, secured. To the extent permitted by, and as provided
in, the Amended Indenture, modifications or alterations of the Amended
Indenture, or of any indenture supplemental thereto, and of the rights and
obligations of the Company and of the holders of the Bonds may be made with the
consent of the Company by an affirmative vote of not less than 60% in amount of
the Bonds entitled to vote then outstanding, at a meeting of Bondholders called
and held as provided in the Amended Indenture, and by an affirmative vote of not
less than 60% in amount of the Bonds of any series entitled to vote then
outstanding and affected by such modification or alteration, in case one or more
but less than all of the series of Bonds then outstanding under the Amended
Indenture are so affected. Additionally, the Company may amend the Amended
Indenture, as supplemented, by an appropriate written consent of not less than
60% in aggregate principal amount of the Bonds outstanding without a meeting of
such Bondholders. No such modification or alteration shall be made which will
affect the terms of payment of the principal of, or interest or premium on, this
Bond, which are unconditional. The Bonds may be issued in series, for various
principal sums, may mature at different times, may bear interest at different
rates and may otherwise vary as in the Amended Indenture provided. This Bond is
one of a series designated as the "First Mortgage Bonds, Senior Notes Series AA"
(herein called the "Bonds of this Series") of the Company, issued under and
secured by the Amended Indenture and described in the indenture (hereinafter
called the "New Supplemental Indenture") dated August 15, 2002, between the
Company and the Trustee, supplemental to the Amended Indenture.

     The Bonds of this Series are not entitled to the benefit of any
improvement, maintenance or analogous fund.

                                       15
<Page>

     This Bond is not redeemable except on the date, in the principal amount and
for the redemption price that correspond to the redemption dates for, the
principal amount to be redeemed of, and the redemption price for, the Senior
Notes, and except upon written demand of the Senior Note Trustee following the
occurrence of an event of default under the Senior Note Indenture and the
acceleration of the Senior Notes, as provided in Section 8.01 of the Senior Note
Indenture.

     In case an event of default, as defined in the Amended Indenture, shall
occur, the principal of all the Bonds at any such time outstanding under the
Amended Indenture may be declared or may become due and payable, upon the
conditions and in the manner and with the effect provided in the Amended
Indenture. The Amended Indenture provides that such declaration may in certain
events be waived by the holders of a majority in principal amount of the Bonds
outstanding.

     This Bond shall not be assignable or transferable except as permitted or
required by Section 4.04 of the Senior Note Indenture. This Bond is exchangeable
by the registered owner hereof, in person or by duly authorized attorney, on the
books of the Company to be kept for that purpose at the office of the Company in
the City of St. Louis, Missouri, upon surrender and cancellation of this Bond
and on presentation of a duly executed written instrument of transfer, and
thereupon a new Bond or Bonds of the same series, of the same aggregate
principal amount and in authorized denominations will be issued to the
transferee or transferees in exchange herefor, without payment of any charge
other than stamp taxes and other governmental charges incident thereto; and this
Bond with or without others of like series, may in like manner be exchanged for
one or more new Bonds of the same series of other authorized denominations but
of the same aggregate principal amount; all subject to the terms and conditions
set forth in the Amended Indenture.

     As provided in Section 4.11 of the Senior Note Indenture, from and after
the Release Date (as defined in the Senior Note Indenture), the obligations of
the Company with respect to this Bond shall be deemed to be satisfied and
discharged, this Bond shall cease to secure in any manner any Senior Notes
outstanding under the Senior Note Indenture, and, pursuant to Section 4.08 of
the Senior Note Indenture, the Senior Note Trustee shall forthwith deliver this
Bond to the Company for cancellation.

     No recourse shall be had for the payment of the principal of, premium, if
any, on or the interest on, this Bond, or for any claim based hereon or on the
Amended Indenture or any indenture supplemental thereto, against any
incorporator, or against any stockholder, director or officer, past, present or
future, of the Company, or of any predecessor or successor corporation, either
directly or through the Company or any such predecessor or successor
corporation, whether for amounts unpaid on stock subscriptions or by virtue of
any constitution, statute or rule of law, or by the enforcement of any
assessment or penalty or otherwise, all such liability, whether at common law,
in equity, by any constitution, statute or otherwise, of incorporators,
stockholders, directors or officers being released by every owner hereof by the
acceptance of this Bond and as part of the consideration for the issue hereof,
and being likewise released by the terms of the Amended Indenture.

                      [END OF FORM OF REVERSE OF NEW BOND]

     Section 4. Until New Bonds in definitive form are ready for delivery, the
Company may execute, and upon its request in writing the Trustee shall
authenticate and deliver, in lieu

                                       16
<Page>

thereof, New Bonds in temporary form, as provided in Section 9 of Article II of
the Original Indenture.

                                   ARTICLE II

                             ISSUE OF THE NEW BONDS

     Section 1. The principal amount of the New Bonds which may be authenticated
and delivered hereunder is limited to an amount equal to the principal amount of
the Senior Notes issued under the Senior Note Indenture and secured thereby and
are further subject to the limitations regarding the principal amount of Bonds
which may be issued under the Original Indenture set forth therein.

     Section 2. The New Bonds in the aggregate principal amount of One Hundred
Seventy Three Million Dollars ($173,000,000), being the initial issue of the New
Bonds, may forthwith at any time or from time to time be executed by the Company
and delivered to the Trustee and shall be authenticated by the Trustee and
delivered (either before or after the filing or recording hereof) to or upon the
order of the Company, upon compliance by the Company with the applicable
provisions of Article III and Article XVIII of the Original Indenture.

     Section 3. For purposes of Section 4.09 of the Senior Note Indenture, the
New Bonds shall be deemed to be the "Related Series of Senior Notes First
Mortgage Bonds" in respect of the Senior Notes.

     Section 4. As provided in Section 4.11 of the Senior Note Indenture, from
and after the Release Date (as defined in the Senior Note Indenture), the
obligations of the Company with respect to the New Bonds shall be deemed to be
satisfied and discharged, the New Bonds shall cease to secure in any manner any
Notes outstanding under the Senior Note Indenture, and, pursuant to Section 4.08
of the Senior Note Indenture, the Senior Note Trustee shall forthwith deliver
the New Bonds to the Company for cancellation.

                                   ARTICLE III

                           REDEMPTION OF THE NEW BONDS

     Section 1. The New Bonds are not redeemable except on the date, in the
principal amount and for the redemption price that correspond to the redemption
date for, the principal amount to be redeemed of, and the redemption price for,
the Senior Notes, and except as set forth in Section 2 of this Article III.

     In the event that the Company redeems any Senior Notes prior to maturity in
accordance with the provisions of the Senior Note Indenture, the Senior Note
Trustee shall on the same date deliver to the Company the New Bonds in principal
amount corresponding to the Senior Notes so redeemed, as provided in Section
4.08 of the Senior Note Indenture. The Company agrees to give the Senior Note
Trustee notice of any such redemption of the Senior Notes on or before the date
fixed for any such redemption.

     There shall be no improvement, maintenance or analogous fund for the New
Bonds.

                                       17
<Page>

     Section 2. Upon the occurrence of an Event of Default under the Senior Note
Indenture and the acceleration of the Senior Notes, the New Bonds shall be
redeemable in whole upon receipt by the Trustee of a written demand (hereinafter
called a "Redemption Demand") from the Senior Note Trustee stating that there
has occurred under the Senior Note Indenture both an Event of Default and a
declaration of acceleration of payment of principal, accrued interest and
premium, if any, on the Senior Notes specifying the last date to which interest
on such Senior Notes has been paid (such date being hereinafter referred to as
the "Initial Interest Accrual Date") and demanding redemption of the New Bonds.
The Company waives any right it may have to prior notice of such redemption
under the Original Indenture. Upon surrender of the New Bonds by the Senior Note
Trustee to the Trustee, the New Bonds shall be redeemed at a redemption price
equal to the principal amount thereof plus accrued interest thereon from the
Initial Interest Accrual Date to the date of the Redemption Demand; provided,
however, that in the event of a rescission or annulment of acceleration of the
Senior Notes pursuant to the last paragraph of Section 8.01(a) of the Senior
Note Indenture, then any Redemption Demand shall thereby deemed to be rescinded
by the Senior Note Trustee although no such rescission or annulment shall extend
to or affect any subsequent default or impair any right consequent thereon.

                                   ARTICLE IV

                                    COVENANTS

     The Company hereby covenants, warrants and agrees;

     Section 1. That the Company is lawfully seized and possessed of all of the
mortgaged property described in the granting clauses of this Supplemental
Indenture; that it has good right and lawful authority to mortgage the same as
provided in this Supplemental Indenture; and that such mortgaged property is, at
the actual date of the issue of the New Bonds, free and clear of any deed of
trust, mortgage, lien, charge or encumbrance thereon or affecting the title
thereto prior to the Original Indenture, except as set forth in the granting
clauses of the Original Indenture or this Supplemental Indenture.

     Section 2. That, so long as any of the New Bonds are outstanding, whenever
any officers' certificate is required to be filed or deposited with the Trustee
pursuant to Section 3(b) of Article III of the Original Indenture upon an
application for the authentication of additional Bonds pursuant to Article III
of the Original Indenture, such officers' certificate shall include, in addition
to the matters required to be stated therein by said Section 3(b), the statement
with respect to the net earnings of the Company available for interest after
property retirement appropriations required by Section 2 of Article V of the
Supplemental Indenture of July 1, 1956.

     Section 3. That, so long as any of the New Bonds are outstanding, the
Company will not apply for the authentication and delivery of additional Bonds
pursuant to Section 4 of Article III of the Original Indenture or the withdrawal
of cash from the trust estate or the reduction of the amount of cash required to
be paid into the trust estate or to satisfy the maintenance and improvement
funds under any provision of the Original Indenture or the Supplemental
Indentures creating prior series of Bonds, on the basis of the amount of
$15,000,000 excluded from net bondable value of property additions not subject
to an unfunded prior lien pursuant to Section 3 of Article V of the Supplemental
Indenture of October 1, 1945, or on the basis of the amount of $7,500,000
excluded from net bondable value of property additions not subject to an

                                       18
<Page>

unfunded prior lien pursuant to Section 3 of Article V of the Supplemental
Indenture of July 1, 1956.

     Section 4. That, so long as any of the New Bonds are outstanding, the
Company will not issue or permit to be issued any prior lien bonds secured by an
unfunded prior lien in addition to the prior lien bonds secured by such unfunded
prior lien at the time of first acquisition by the Company of property subject
thereto (other than in lieu of lost, stolen or mutilated bonds or on the
exchange for bonds already outstanding of an equal principal amount of other
bonds of the same issue and the same series, if any, and of the same maturity),
except upon compliance with the provisions of Section 16 of Article IV of the
Original Indenture, nor unless the net earnings of the Company available for
interest after property retirement appropriations (determined as provided in
Section 2 of Article V of the Supplemental Indenture of July 1, 1956), for any
twelve consecutive calendar months during the period of fifteen calendar months
immediately preceding the first day of the month in which the additional prior
lien bonds are to be issued, have been, in the aggregate, equal to not less than
twice the annual interest charges on the indebtedness specified in subparagraphs
(i) and (ii) of paragraph (1) of Section 2(a) of said Article V; provided that,
if the application for the issue of such additional prior lien bonds is upon the
basis of payment at maturity of prior lien bonds theretofore sold or otherwise
disposed of or the redemption or purchase thereof after a date two years prior
to the date of maturity, the additional requirement imposed by this Section 4
with respect to net earnings of the Company available for interest after
property retirement appropriations shall not apply. Any officers' certificate
with respect to net earnings of the Company, required to be filed with the
Trustee as a condition precedent to the issue of such additional prior lien
bonds, shall include, in addition to the matters otherwise required to be stated
therein, the matters required to be stated in an officers' certificate pursuant
to paragraphs (1) and (2) of Section 2(a) of said Article V.

     Section 5. That, so long as any of the New Bonds are outstanding, the
Company will not acquire, by purchase, merger or otherwise, any property subject
to a lien or liens which will on acquisition be an unfunded prior lien or prior
liens, except upon compliance with the provisions of Section 14 of Article IV of
the Original Indenture, nor unless the net earnings of such property available
for interest after property retirement appropriations (determined in the manner
provided in Section 2 of Article V of the Supplemental Indenture of July 1,
1956), for any twelve consecutive calendar months during the period of fifteen
calendar months immediately preceding the first day of the month in which the
first acquisition of property subject to such lien or liens occurs, have been,
in the aggregate, equal to not less than twice the amount of annual interest
charges, on all outstanding indebtedness secured by such lien or liens. Any
officers' certificate with respect to net earnings of such property, required to
be filed with the Trustee as a condition precedent to the acquisition of such
property, shall include, in addition to the matters otherwise required to be
stated therein, the matters required to be stated in an officers' certificate
pursuant to Section 2 of said Article V applicable, however, only to the net
earnings of such property and to the indebtedness secured by such liens to which
such property is subject.

                                       19
<Page>

                                    ARTICLE V

                                   THE TRUSTEE

     The Trustee hereby accepts the trusts hereby declared and provided, and
agrees to perform the same upon the terms and conditions in the Original
Indenture and in this Supplemental Indenture set forth, and upon the following
terms and conditions:

     The Trustee shall not be responsible in any manner whatsoever for or in
respect of the validity or sufficiency of this Supplemental Indenture or the due
execution hereof by the Company or for or in respect of the recitals contained
herein, all of which recitals are made by the Company solely.

                                   ARTICLE VI

           AMENDMENTS OF CERTAIN PROVISIONS OF THE ORIGINAL INDENTURE.

     Section 1. Pursuant to the reservation of right in the Supplemental
Indenture of August 16, 1976 and each supplemental indenture dated thereafter,
and there being no outstanding Bonds of any series created prior to the Bonds
created by such Supplemental Indenture of August 16, 1976, the Company hereby
amends the Original Indenture, as supplemented, so as to substitute in Article
XV thereof "sixty percent (60%)" for "eighty percent (80%)" wherever appearing
in said Article XV.

     Section 2. Pursuant to the reservation of right in the Supplemental
Indenture of August 16, 1976 and each supplemental indenture dated thereafter,
and there being no outstanding Bonds of any series created prior to the Bonds
created by such Supplemental Indenture of August 16, 1976, the Company hereby
amends the Original Indenture, as supplemented, to amend Article XV thereof by
adding thereto a Section 9 to read as follows:

          "SECTION 9. (A) Anything in this Article XV contained to the contrary
          notwithstanding, the Trustee shall receive the written consent (in any
          number of instruments of similar tenor executed by Bondholders or by
          their attorneys appointed in writing) of the holders of sixty percent
          (60%) or more in principal amount of the Bonds outstanding hereunder,
          and, if the rights of one or more, but less than all, series of Bonds
          then outstanding are to be affected by action taken pursuant to such
          consent, then also by consent of the holders of at least sixty percent
          (60%) in principal amount of each series of Bonds so to be affected
          and outstanding hereunder (at the time the last such needed consent is
          delivered to the Trustee) in lieu of the holding of a meeting pursuant
          to this Article XV and in lieu of all action at such a meeting and
          with the same force and effect as a resolution duly adopted in
          accordance with the provisions of Section 6 of this Article XV.

               (B) Instruments of consent shall be witnessed or in the
          alternative may (a) have the signature guaranteed by a bank or trust
          company or a registered dealer in securities, (b) be acknowledged
          before a Notary Public or other officer authorized to take
          acknowledgements, or (c)

                                       20
<Page>

          have their genuineness otherwise established to the satisfaction of
          the Trustee.

               The amount of Bonds payable to bearer, and the series and serial
          numbers thereof, held by a person executing an instrument of consent
          (or whose attorney has executed an instrument of consent in his
          behalf), and the date of his holding the same may be proved by
          exhibiting the Bonds to and obtaining a certificate executed by (i)
          any bank or trust or insurance company, or (ii) any trustee,
          secretary, administrator or other proper officer of any pension,
          welfare, hospitalization or similar fund or funds, or (iii) the United
          States of America, any Territory thereof, the District of Columbia,
          any State of the United States or any public instrumentality of the
          United States, or of any State or of any Territory, or (iv) any other
          person or corporation satisfactory to the Trustee. A Bondholder in any
          of the foregoing categories may sign a certificate in his own behalf.

               Each such certificate shall be dated and shall state, in effect,
          that as of the date thereof, a coupon Bond or Bonds bearing a
          specified serial number or numbers was deposited with or exhibited to
          the signer of such certificate. The holding by the person named in any
          such certificate of any Bond specified therein shall be presumed to
          continue unless (1) any certificate bearing a later date issued in
          respect of the same Bond shall be produced, (2) the Bond specified in
          such certificate (or any Bond or Bonds issued in exchange or
          substitution for such Bond) shall be produced by another holder, or
          (3) the Bond specified in such certificate shall be registered as to
          principal in the name of another holder or shall have been surrendered
          in exchange for a fully registered bond registered in the name of
          another holder. The Trustee may nevertheless, in his discretion,
          require further proof in cases where it deems further proof desirable.
          The ownership of registered Bonds shall be proved by the registry
          books.

               (C) Until such time as the Trustee shall receive the written
          consent of the necessary per cent. in principal amount of the Bonds
          required by the provisions of subsection (A) above for action
          contemplated by such consent, any holder of a Bond, the serial number
          of which is shown by the evidence to be included in the Bonds the
          holders of which have consented to such action, may, by filing written
          notice with the Trustee at its principal office and upon proof of
          holding as provided in subsection (B) above, revoke such consent so
          far as it concerns such Bond. Except as aforesaid, any such action
          taken by the holder of any Bond shall be conclusive and binding upon
          such holder and upon all future holders of such Bond (and any Bond
          issued in lieu thereof or exchanged therefor), irrespective of whether
          or not any notation of such consent is made upon such Bond, and in any
          event any action taken by the holders of the percentage in aggregate
          principal amount of the Bonds specified in subsection (A) above in
          connection with such action shall be conclusively binding upon the
          Company, the Trustee and the holders of all the Bonds."

                                       21
<Page>

                                   ARTICLE VII

                            MISCELLANEOUS PROVISIONS.

     Section 1. Except as otherwise defined herein, all terms contained in this
Supplemental Indenture shall, for all purposes thereof, have the meanings given
to such terms in Article I of the Original Indenture.

     Section 2. This Supplemental Indenture may be simultaneously executed in
any number of counterparts, each of which when so executed shall be deemed to be
an original; but such counterparts shall together constitute but one and the
same instrument.

                                       22
<Page>

     IN WITNESS WHEREOF, said Union Electric Company has caused this
Supplemental Indenture to be executed on its behalf by its Chairman of the Board
or President or one of its Vice Presidents and its corporate seal to be hereto
affixed and said seal and this Supplemental Indenture to be attested by its
Secretary or one of its Assistant Secretaries; and said The Bank of New York, in
evidence of its acceptance of the trust hereby created, has caused this
Supplemental Indenture to be executed on its behalf by its President or one of
its Vice Presidents, and its corporate seal to be hereto affixed and said seal
and this Supplemental Indenture to be attested by its Secretary, or one of its
Assistant Secretaries; all as of the 15th day of August, Two thousand and two.

Attested:                               UNION ELECTRIC COMPANY,
                                           1901 Chouteau Avenue
                                           St. Louis, Missouri 63103

       /s/ G. L. Waters                 By:       /s/ Warner L. Baxter
----------------------------------         -----------------------------
     G. L. Waters                       Name:  Warner L. Baxter
     Assistant Secretary                Title: Senior Vice President

Signed, sealed and delivered by
   UNION ELECTRIC COMPANY
   in the presence of:

       /s/ Daphyne H. Bradley
----------------------------------
     Daphyne H. Bradley

       /s/ D. T. McGillicuddy
----------------------------------
     D. T. McGillicuddy
            As Witnesses

Attested:                               THE BANK OF NEW YORK,
                                           911 Washington Avenue
                                           St. Louis, Missouri 63101

       /s/ Linda Krull                  By:    /s/ J. Bruce Herd
----------------------------------         -------------------------------------
    Linda Krull                         Name:  J. Bruce Herd
    As Agent for The Bank of New York   Title: As Agent for the Bank of New York

Signed, sealed and delivered by
    THE BANK OF NEW YORK
    in the presence of:

       /s/ P. C. QuiBelle
----------------------------------
    P. C. QuiBelle

       /s/ N. Mogelnicki
----------------------------------
    N. Moglenicki
            As Witnesses

                                       23
<Page>

STATE OF MISSOURI,         }
                           } SS.:
CITY OF ST. LOUIS,         }

     On this 19th day of August 2002, before me appeared WARNER L. BAXTER, to me
personally known, who, being by me duly sworn, did say that he is a Senior Vice
President of THE BANK OF NEW YORK, a corporation, and that the seal affixed to
the foregoing instrument is the corporate seal of said corporation, and that
said instrument was signed and sealed in behalf of said corporation, as the
trustee thereunder by authority of its Board of Directors, and said WARNER L.
BAXTER, acknowledged said instrument to be the free act and deed of said
corporation as the trustee under said instrument.

     IN TESTIMONY WHEREOF, I have hereto set my hand and affixed my official
seal at my office, in the City and State aforesaid, the day and year last above
written.

                                           /s/ Mary Hoyt
                                      ------------------------------------------
                                           Mary Hoyt

                                      MARY HOYT
                                      NOTARY PUBLIC - NOTARY SEAL
                                      STATE OF MISSOURI
                                      JEFFERSON COUNTY
                                      MY COMMISSION EXPIRES APRIL 1, 2006

                                       24
<Page>

STATE OF MISSOURI,         }
                           } SS.:
CITY OF ST. LOUIS,         }

     On this 19th day of August 2002, before me appeared WARNER L. BAXTER, to me
personally known, who, being by me duly sworn, did say that he is a Senior Vice
President of THE BANK OF NEW YORK, a corporation, and that the seal affixed to
the foregoing instrument is the corporate seal of said corporation, and that
said instrument was signed and sealed in behalf of said corporation, as the
trustee thereunder by authority of its Board of Directors, and said WARNER L.
BAXTER, acknowledged said instrument to be the free act and deed of said
corporation as the trustee under said instrument.

     IN TESTIMONY WHEREOF, I have hereto set my hand and affixed my official
seal at my office, in the City and State aforesaid, the day and year last above
written.

                                           /s/ Mary Hoyt
                                      ------------------------------------------
                                           Mary Hoyt

                                      MARY HOYT
                                      NOTARY PUBLIC - NOTARY SEAL
                                      STATE OF MISSOURI
                                      JEFFERSON COUNTY
                                      MY COMMISSION EXPIRES APRIL 1, 2006

                                       25

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00042-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00042-of-00352.parquet"}]]