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                                                                     Exhibit 4.3



REGISTERED                                                            REGISTERED

                            Ill. C. C. No. 6277

       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
                       4.75% SENIOR SECURED NOTE DUE 2015

CUSIP:   906548BZ4                               NUMBER: 1
ISIN:    US906548BZ47
ORIGINAL ISSUE DATE:  April 9, 2003              PRINCIPAL AMOUNT:  $114,000,000

INTEREST RATE:  4.75%                            MATURITY DATE:  April 1, 2015

       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 FOURTEEN MILLION DOLLARS
($114,000,000) on the Maturity Date set forth above, and to pay interest thereon
from April 9, 2003 or from the most recent Interest Payment Date to which
interest has been paid or duly provided for, semi-annually in arrears on the
April 1 and October 1 in each year, commencing October 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 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
March 15 or September 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 Date of which is after a Regular Record Date


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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
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 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 4.75%
Senior Secured Notes due 2015 (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 $114,000,000.

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


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       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.

       The Notes of this Series are not redeemable by the Company prior to the
Maturity 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 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 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

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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, 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 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.






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

                                  UNION ELECTRIC COMPANY


                                  By:     /s/ Jerre E. Birdsong
                                          --------------------------------------

                                  Title:  Vice President and Treasurer
                                          --------------------------------------

                                  Attest: /s/ Ronald K. Evans
                                          --------------------------------------

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

TRUSTEE'S CERTIFICATE
OF AUTHENTICATION

Dated:  April 9, 2003

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/ Belinda Brown
   --------------------------------
         AUTHORIZED SIGNATORY


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                                  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:

<Table>
<S>                                            <C>
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
</Table>

                    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


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


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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").