Unassociated Document


    Exhibit
      4(a)


    


    


    
      


    

    


    


    


    


    


    


    


    PUBLIC
      SERVICE COMPANY OF OKLAHOMA

    


    


    and

    


    


    THE
      BANK
      OF NEW YORK,

    AS
      TRUSTEE

    


    


    ___________________

    


    


    SEVENTH
      SUPPLEMENTAL INDENTURE

    


    Dated
      as
      of November 14, 2007

    


    


    Supplemental
      to the Indenture

    dated
      as
      of November 1, 2000

    


    


    


    


    


    6.625%
      Senior Notes, Series G, Due 2037

    


    


    


    


    
      


    

    SEVENTH
      SUPPLEMENTAL INDENTURE, dated
      as of November 14, 2007, between PUBLIC SERVICE COMPANY OF OKLAHOMA, a
      corporation duly organized and existing under the laws of the State of Oklahoma
      (the "Company"), and THE BANK OF NEW YORK, a New York banking corporation
      organized and existing under the laws of the State of New York, as Trustee
      under
      the Original Indenture referred to below (the "Trustee").

    


    RECITALS
      OF THE COMPANY

     

    The
      Company has heretofore executed and
      delivered to the Trustee an indenture dated as of November 1, 2000 (the
      "Original Indenture"), to provide for the issuance from time to time of its
      debentures, notes or other evidences of indebtedness (the "Senior Notes"),
      the
      form and terms of which are to be established as set forth in Section 201 and
      301 of the Original Indenture.

    


    Section
      901 of the Original Indenture
      provides, among other things, that the Company and the Trustee may enter into
      indentures supplemental to the Original Indenture for, among other things,
      the
      purpose of establishing the form and terms of the Senior Notes of any series
      as
      permitted in Sections 201 and 301 of the Original Indenture.

    


    The
      Company desires to create a series
      of the Senior Notes in an aggregate principal amount of $250,000,000 to be
      designated the "6.625% Senior Notes, Series G, Due 2037" (the "Series G Notes"),
      and all action on the part of the Company necessary to authorize the issuance
      of
      the Series G Notes under the Original Indenture and this Seventh Supplemental
      Indenture has been duly taken.

    


    All
      acts and things necessary to make
      the Series G Notes, when executed by the Company and completed, authenticated
      and delivered by the Trustee as provided in the Original Indenture and this
      Seventh Supplemental Indenture, the valid and binding obligations of the Company
      and to constitute these presents a valid and binding supplemental indenture
      and
      agreement according to its terms, have been done and performed.

    


    NOW,
      THEREFORE, THIS SEVENTH
      SUPPLEMENTAL INDENTURE WITNESSETH:

    


    That
      in
      consideration of the premises and of the acceptance and purchase of the Series
      G
      Notes by the Holders thereof and of the acceptance of this trust by the Trustee,
      the Company covenants and agrees with the Trustee, for the equal benefit of
      the
      Holders of the Series G Notes, as follows:

    


    ARTICLE
      ONE

    Definitions

    


    SECTION
      101. DEFINITIONS.

    


    The
      use of the terms and expressions
      herein is in accordance with the definitions, uses and constructions contained
      in the Original Indenture and the form of the Series G Notes attached hereto
      as
Exhibit A.

     

    ARTICLE
      TWO

    Terms
      and
      Issuance of the 6.625% Senior Notes, Series G, Due 2037

    


    SECTION
      201.  Issue of the Series G Notes.

    


    A
      series of Senior Notes which shall be
      designated the "6.625% Senior Notes, Series G, Due 2037" shall be executed,
      authenticated and delivered in accordance with the provisions of, and shall
      in
      all respects be subject to, the terms, conditions and covenants of, the Original
      Indenture and this Seventh Supplemental Indenture (including the form of Series
      G Notes set forth in Exhibit A hereto).  The aggregate
      principal amount of the Series G Notes which may be authenticated and delivered
      under this Seventh Supplemental Indenture shall initially be $250,000,000,
      and
      such principal amount of the Series G Notes may be increased from time to
      time.  All Series G Notes need not be issued at the same time and such
      series may be reopened at any time, without the consent of any Holder, for
      issuance of additional Series G Notes.  Any such additional Series G
      Notes will have the same interest rate, maturity and other terms as those
      initially issued.

    


    SECTION
      202.  Form of Series G Notes; Incorporation of
      Terms.

    


    The
      Series G Notes shall be issued
      initially in the form of one Global Security.  The form of the Series
      G Notes shall be substantially in the form of Exhibit A attached
      hereto.  The terms of such Series G Notes are herein incorporated by
      reference and are part of this Seventh Supplemental Indenture.

    


    SECTION
      203.  Depositary for Global Securities.

    


    The
      Depositary for any Global
      Securities of the series of which this Series G Note is a part shall be the
      Depository Trust Company in The City of New York.

    


    SECTION
      204.  Restriction on Liens.

    


    The
      covenant contained in Section 1007 of the Original Indenture shall not be
      applicable to the Series G Notes.

    


    So
      long
      as any of the Series G Notes are outstanding, the Company will not create or
      suffer to be created or to exist any additional mortgage, pledge, security
      interest, or other lien (collectively "Liens") on any of its utility properties
      or tangible assets now owned or hereafter acquired to secure any indebtedness
      for borrowed money ("Secured Debt"), without providing that the Series G Notes
      will be similarly secured.  This restriction does not apply to the
      Company's subsidiaries, nor will it prevent any of them from creating or
      permitting to exist Liens on their property or assets to secure any Secured
      Debt.  In addition, this restriction does not prevent the creation or
      existence of:

    


    
      	 	
              (a)

            	
              Liens
                on property existing at the time of acquisition or construction of
                such
                property (or created within one year after completion of such acquisition
                or construction), whether by purchase, merger, construction or otherwise,
                or to secure the payment of all or any part of the purchase price
                or
                construction cost thereof, including the extension of any Liens to
                repairs, renewals, replacements, substitutions, betterments, additions,
                extensions and improvements then or thereafter made on the property
                subject thereto;

            
	 	 	 
	 	
              (b)

            	
              Financing
                of the Company's accounts receivable for electric
                service;

            
	 	 	 
	 	
              (c)

            	
              Any
                extensions, renewals or replacements (or successive extensions, renewals
                or replacements), in whole or in part, of liens permitted by the
                foregoing
                clauses; and

            
	 	 	 
	 	
              (d)

            	
              The
                pledge of any bonds or other securities at any time issued under
                any of
                the Secured Debt permitted by the above
                clauses.

            


    

    


    In
      addition to the permitted issuances above, Secured Debt not otherwise so
      permitted may be issued in an amount that does not exceed 15% of Net Tangible
      Assets as defined below.

    


    “Net
      Tangible Assets” means the total of all assets (including revaluations thereof
      as a result of commercial appraisals, price level restatement or otherwise)
      appearing on the Company’s balance sheet, net of applicable reserves and
      deductions, but excluding goodwill, trade names, trademarks, patents,
      unamortized debt discount and all other like intangible assets (which term
      shall
      not be construed to include such revaluations), less the aggregate of the
      Company’s current liabilities appearing on such balance sheet.  For
      purposes of this definition, the Company’s balance sheet does not include assets
      and liabilities of its subsidiaries.

    


    This
      restriction also does not apply to or prevent the creation or existence of
      leases made, or existing on property acquired, in the ordinary course of
      business.

    


    SECTION
      205.          Place of
      Payment.

    


    The
      Place of Payment in respect of the
      Series G Notes will be at the principal office or place of business of the
      Trustee or its successor in trust under the Indenture, which, at the date
      hereof, is located at 101 Barclay Street, New York, NY 10286, Attention:
      Corporate Trust Administration.

    


    SECTION
      206.  Optional Redemption.

    


    The
      Series G Notes may be redeemed at the Company’s option at any time upon no more
      than 60 and not less than 30 days’ notice by mail.  The Series G Notes
      may be redeemed either as a whole or in part at a redemption price equal to
      the
      greater of (1) 100% of the principal amount of the Series G Notes being redeemed
      and (2) the sum of the present values of the remaining scheduled payments of
      principal and interest on the Series G Notes being redeemed (excluding the
      portion of any such interest accrued to the date of redemption) discounted
      (for
      purposes of determining present value) to the redemption date on a semi-annual
      basis (assuming a 360-day year consisting of twelve 30-day months) at the
      Treasury Rate (as defined below) plus 30 basis points; plus, in each case,
      accrued interest thereon to the date of redemption.

    


    "Business
      Day" means any day that is not a day on which banking institutions in New York
      City are authorized or required by law or regulation to close.

    


    “Comparable
      Treasury Issue” means the
      United States Treasury security selected by an Independent Investment Banker
      as
      having a maturity comparable to the remaining term (“remaining life”) of the
      Series G Notes 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 life of the Series
      G
      Notes.

    


    “Comparable
      Treasury Price” means, with
      respect to any redemption date, (1) the average of the Reference Treasury Dealer
      Quotations for such redemption date, after excluding the highest and lowest
      such
      Reference Treasury Dealer Quotations, or (2) if the Company obtains fewer than
      four such Reference Treasury Dealer Quotations, the average of all such
      quotations.

    


    “Independent
      Investment Banker” means
      one of the Reference Treasury Dealers appointed by the Company and reasonably
      acceptable to the Trustee.

    


    “Reference
      Treasury Dealer” means
      Citigroup Global Markets Inc., Merrill Lynch, Pierce, Fenner & Smith
      Incorporated, Morgan Stanley & Co. Incorporated and UBS Securities LLC and
      their respective successors; provided, however, that if any of the foregoing
      shall cease to be primary U.S. government securities dealers the Company will
      substitute therefor another primary U.S. government securities dealer reasonably
      acceptable to the Trustee.

    


    “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 or before 3:30 p.m., New York City time, on the third Business Day
      preceding such redemption date.

    


    “Treasury
      Rate” means, with respect to
      any redemption date: (i) the yield, under the heading which represents the
      average for the week immediately preceding the date on which the notice of
      redemption is mailed to the registered Holders of the Securities (the
“calculation date”), appearing in the most recently published statistical
      release designated “H.15(519)” or any successor publication which is published
      weekly by the Board of Governors of the Federal Reserve System and which
      establishes yields on actively traded U.S. Treasury securities adjusted to
      constant maturity under the caption “Treasury Constant Maturities,” for the
      maturity corresponding to the Comparable Treasury Issue (if no maturity is
      within three months before or after the remaining life (as defined above),
      yields for the two published maturities most closely corresponding to the
      Comparable Treasury Issue will be determined by the Independent Investment
      Banker and the Treasury Rate will be interpolated or extrapolated from such
      yields by the Independent Investment Banker on a straight line basis, rounding
      to the nearest month); or (ii) if such release (or any successor release) is
      not
      published during the week preceding the calculation date or does not contain
      such yields, the rate per annum equal to the semiannual equivalent yield to
      maturity of the Comparable Treasury Issue, calculated by the Independent
      Investment Banker using 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.

    


    SECTION
      207.  Sinking Funds.

    


    Article
      Twelve of the Indenture shall not apply to the Series G Notes.

    


    SECTION
      208.  Regular Record Date.

    


    The
      "Regular Record Date" will be the May 1 or November 1, as the case may be,
      next
      preceding an interest payment date.

    


    ARTICLE
      THREE

    Miscellaneous

    


    SECTION
      301.  Execution as Supplemental Indenture.

    


    This
      Seventh Supplemental Indenture is executed and shall be construed as an
      indenture supplemental to the Original Indenture and, as provided in the
      Original Indenture, this Seventh Supplemental Indenture forms a part
      thereof.

    


    SECTION
      302.  Conflict with Trust Indenture Act.

    


    If
      any
      provision hereof limits, qualifies or conflicts with another provision hereof
      which is required to be included in this Seventh Supplemental Indenture by
      any
      of the provisions of the Trust Indenture Act, such required provision shall
      control.

    


    SECTION
      303.  Effect of Headings.

    


    The
      Article and Section headings herein are for convenience only and shall not
      affect the construction hereof.

    


    SECTION
      304.  Successors and Assigns.

    


    All
      covenants and agreements by the Company in this Seventh Supplemental Indenture
      shall bind its successors and assigns, whether so expressed or not.

    


    SECTION
      305.  Separability Clause.

    


    In
      case
      any provision in this Seventh Supplemental Indenture or in the Series G Notes
      shall be invalid, illegal or unenforceable, the validity, legality and
      enforceability of the remaining provisions shall not in any way be affected
      or
      impaired thereby.

    


    SECTION
      306.  Benefits of Seventh Supplemental Indenture.

    


    Nothing
      in this Seventh Supplemental Indenture or in the Series G Notes, express or
      implied, shall give to any Person, other than the parties hereto and their
      successors hereunder and the Holders, any benefit or any legal or equitable
      right, remedy or claim under this Seventh Supplemental Indenture.

    


    SECTION
      307.  Execution and Counterparts.

    


    This
      Seventh Supplemental Indenture may be executed in any number of counterparts,
      each of which shall be deemed to be an original, but all such counterparts
      shall
      together constitute but one and the same instrument.

    


    


    [REMAINDER
      OF PAGE INTENTIONALLY LEFT BLANK]

    
       

       

       

    

    IN
      WITNESS WHEREOF, the parties hereto have caused this Seventh Supplemental
      Indenture to be duly executed and attested, all as of the day and year first
      above written.

    


    


    PUBLIC
      SERVICE COMPANY OF
      OKLAHOMA

    


    


    By__/s/
      Stephan T.
      Haynes                                                                           

    Name: 
Stephan
      T.
      Haynes

    Title:    
      Assistant Treasurer

    


    Attest:

    


    


    _/s/
      Thomas G.
      Berkemeyer                                                                           

    Name: 
      Thomas G. Berkemeyer

    Title:    
      Assistant Secretary

    


    THE
      BANK OF NEW YORK, as
      Trustee

    


    


    By_
      /s/ Mary
      LaGumina                                                                

    Authorized
      Signatory

    


    Attest:

    


    


    __/s/_Beata
      Hryniewicka__________

    Authorized
      Signatory


    
       

       

       

    

    STATE
      OF
      OHIO                                )

                   :
      ss.:

    COUNTY
      OF
      FRANKLIN                 )

    


    


    On
      the 14th  day of
      November, 2007, personally appeared before me, a Notary Public within and for
      said County in the State of Ohio, Stephan T. Haynes and Thomas G. Berkemeyer,
      to
      me known and known to me to be respectively the Assistant Treasurer and
      Assistant Secretary of Public Service Company of Oklahoma, one of the
      corporations named in and which executed the foregoing instrument, who severally
      acknowledged that they did sign said instrument as such Assistant Treasurer
      and
      Assistant Secretary for and on behalf of said corporation and that the same
      is
      their free act and deed as such Assistant Treasurer and Assistant Secretary,
      respectively, and the free and corporate act and deed of said
      corporation.

    


    In
      witness whereof, I have hereunto set my hand notarial seal this 14th day of
      November,
      2007.

    


    


    


    /s/
      David C.
      House                                                                

    


    


    


    


    


    STATE
      OF
      NEW YORK         )

     
  :
      ss.:

    COUNTY
      OF
      NEW YORK    )

    


    


    On
      the 14th day of
      November,
      2007, personally appeared before me, a Notary Public within and for said County
      in the State of New York, Mary LaGumina and Beata Hryniewicka, to me known
      and
      known to me to be respectively the Vice President and Assistant Vice President
      of The Bank of New York, one of the corporations named in and which executed
      the
      foregoing instrument, who severally acknowledged that they did sign said
      instrument as such Vice President and Assistant Vice President for and on behalf
      of said corporation and that the same is their free act and deed as such Vice
      President and Assistant Vice President, respectively, and the free and corporate
      act and deed of said corporation.

    


    In
      witness whereof, I have hereunto set my hand notarial seal this 14th day of
      November,
      2007.

    


    


    ___/s/
      Carlos R.
      Luciano_________________


    
       

       

       

    

     

    Exhibit
      A

    


    THIS
      SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE HEREINAFTER
      REFERRED TO AND IS REGISTERED IN THE NAME OF A DEPOSITARY OR A NOMINEE OF A
      DEPOSITARY.  THIS SECURITY IS EXCHANGEABLE FOR SECURITIES REGISTERED
      IN THE NAME OF A PERSON OTHER THAN THE DEPOSITARY OR ITS NOMINEE ONLY IN THE
      LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE, AND NO TRANSFER OF THIS
      SECURITY (OTHER THAN A TRANSFER OF THIS SECURITY 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) MAY BE REGISTERED EXCEPT IN LIMITED
      CIRCUMSTANCES.

     

    Unless
      this certificate is presented by an authorized representative of The Depository
      Trust Company, a New York corporation (“DTC”), to Public Service Company of
      Oklahoma or its agent for registration of transfer, exchange or payment, and
      any
      definitive certificate issued is registered in the name of Cede & Co. or in
      such other name as is requested by an authorized representative of DTC (and
      any
      payment is made to Cede & Co. or to such other entity as is requested by an
      authorized representative of DTC), ANY TRANSFER, PLEDGE, OR OTHER USE HEREOF
      FOR
      VALUE OR OTHERWISE BY OR TO ANY PERSON IS WRONGFUL in as much as the registered
      owner hereof, Cede & Co., has an interest herein.

     

    No.
      R-1

    


    PUBLIC
      SERVICE COMPANY OF OKLAHOMA

    6.625%
      Senior Notes, Series G, due 2037

    


    CUSIP
      No.
      744533
      BJ8                                                                                                                                                                                   
      $250,000,000

    


    PUBLIC
      SERVICE COMPANY OF OKLAHOMA, a corporation duly organized and existing under
      the
      laws of the State of Oklahoma (the “Company”, which term includes any successor
      Person under the Indenture hereinafter referred to), for value received, hereby
      promises to pay to CEDE & CO. or registered assigns, the principal sum of
      TWO HUNDRED FIFTY MILLION DOLLARS ($250,000,000) on November 15, 2037 (the
      “Final Maturity”), and to pay interest thereon from November 14, 2007 or from
      the most recent Interest Payment Date to which interest has been paid or duly
      provided for, semi-annually on May 15 and November 15 each year, commencing
      May
      15, 2008, at the interest rate per annum specified above, until the principal
      amount shall have been paid or duly provided for.  Interest shall be
      computed on the basis of a 360-day year of twelve 30-day months.

    


    The
      interest so payable, and punctually paid or duly provided for, on any Interest
      Payment Date will, as provided in such Indenture, be paid to the Person in
      whose
      name this Security (or one or more Predecessor Securities) is registered at
      the
      close of business on the Regular Record Date for such interest, which shall
      be
      the May 1 or November 1 (whether or not a Business Day) immediately preceding
      the Interest Payment Date.  Any such interest not so punctually paid
      or duly provided for will forthwith cease to be payable to the Holder on such
      Regular Record Date and may either be paid to the Person in whose name this
      Security (or one or more Predecessor Securities) 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 Holders of Securities
      of this series not less than 10 days prior to such Special Record Date, or
      be
      paid at any time in any other lawful manner not inconsistent with the
      requirements of any securities exchange on which the Securities of this series
      may be listed, and upon such notice as may be required by such exchange, all
      as
      more fully provided in said Indenture.

    


    Payment
      of the principal of (and premium, if any) and interest on this Security will
      be
      made at the office or agency of the Company maintained for that purpose in
      the
      Borough of Manhattan, The City of New York, New York, in such coin or currency
      of the United States of America as at the time of payment is legal tender for
      the payment of public and private debts; provided, however, that at the option
      of the Company payment of interest may be made by check mailed to the address
      of
      the Person entitled thereto as such address shall appear in the Security
      Register.

    


    This
      Security has initially been issued in the form of a Global Security, and the
      Company has initially designated The Depository Trust Company (the “Depositary”,
      which term shall include any successor depositary) as the depositary for this
      Security.  For as long as this Security or any portion hereof is
      issued in such form, and notwithstanding the previous paragraph, all payments
      of
      interest, principal and other amounts in respect of this Security or portion
      thereof shall be made to the Depositary or its nominee in accordance with the
      Applicable Procedures in the coin or currency specified above and as further
      provided herein.

    


    This
      Security is one of a duly authorized issue of securities of the Company (the
      “Securities”), issued and to be issued in one or more series under an Indenture,
      dated as of November 1, 2000, as amended and supplemented from time to time
      (the
“Indenture”, which term shall have the meaning assigned to it in such
      instrument), between the Company and The Bank of New York, a New York banking
      corporation, as Trustee (the “Trustee”, which term includes any successor
      trustee under the Indenture), as to which Indenture and all indentures
      supplemental thereto reference is hereby made for a statement of the respective
      rights, limitations of rights, duties and immunities thereunder of the Company,
      the Trustee and the Holders and of the terms upon which the Securities are,
      and
      are to be, authenticated and delivered.  This Security is one of the
      series designated on the face hereof, limited in aggregate principal amount
      to
      $250,000,000; provided, however, the aggregate principal amount hereof can
      be
      increased, without the consent of the Holder, as permitted by the provisions
      of
      the Original Indenture.  The provisions of this Security, together
      with the provisions of the Indenture, shall govern the rights, obligations,
      duties and immunities of the Holder, the Company and the Trustee with respect
      to
      this Security, provided that, if any provision of this Security necessarily
      conflicts with any provision of the Indenture, the provision of this Security
      shall be controlling to the fullest extent permitted under the
      Indenture.

    


    The
      Securities of this Series are subject to redemption upon not less than 30 nor
      more than 60 days’ notice by mail to the Holders of such Securities at their
      addresses in the Security Register for such Series at the option of the Company,
      in whole or in part, from time to time at a Redemption Price equal to the
      greater of (i) 100% of the principal amount of the Securities being redeemed
      and
      (ii) the sum of the present values of the remaining scheduled payments of
      principal and interest on the Securities being redeemed (excluding the portion
      of any such interest accrued to the date of redemption) discounted (for purposes
      of determining present value) to the redemption date on a semi-annual basis
      (assuming a 360-day year consisting of twelve 30-day months) at the Treasury
      Rate (as defined below) plus 30 basis points, plus, in each case, accrued
      interest thereon to the date of redemption.

    


    “Comparable
      Treasury Issue” means the United States Treasury security selected by an
      Independent Investment Banker as having a maturity comparable to the remaining
      term (“remaining life”) of the Securities 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
      life
      of the Securities.

    


    “Comparable
      Treasury Price” means, with respect to any redemption date, (1) the average of
      the Reference Treasury Dealer Quotations for such redemption date after
      excluding the highest and lowest such Reference Treasury Dealer Quotations,
      or
      (2) if fewer than four such Reference Treasury Dealer Quotations are obtained,
      the average of all such quotations.

    


    “Independent
      Investment Banker” means one of the Reference Treasury Dealers appointed by the
      Company and reasonably acceptable to the Trustee.

    


    “Reference
      Treasury Dealer” means Citigroup Global Markets Inc., Merrill Lynch, Pierce,
      Fenner & Smith Incorporated, Morgan Stanley & Co. Incorporated and UBS
      Securities LLC and their respective successors; provided, however, that if
      any
      of the foregoing shall cease to be primary U.S. government securities dealers
      the Company will substitute therefor another primary U. S. government securities
      dealer reasonably acceptable to the Trustee.

    


    “Reference
      Treasury Dealer Quotations” mean, 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 or before 3:30 p.m., New York City time, on the
      third Business Day preceding such redemption date.

    


    “Treasury
      Rate” means, with respect to any redemption date: (i) the yield, under the
      heading which represents the average for the week immediately preceding the
      date
      on which the notice of redemption is mailed to the registered Holders of the
      Securities (the “calculation date”), appearing in the most recently published
      statistical release designated “H.15(519)” or any successor publication which is
      published weekly by the Board of Governors of the Federal Reserve System and
      which establishes yields on actively traded U.S. Treasury securities adjusted
      to
      constant maturity under the caption “Treasury Constant Maturities,” for the
      maturity corresponding to the Comparable Treasury Issue (if no maturity is
      within three months before or after the remaining life (as defined above),
      yields for the two published maturities most closely corresponding to the
      Comparable Treasury Issue will be determined by the Independent Investment
      Banker and the Treasury Rate will be interpolated or extrapolated from such
      yields by the Independent Investment Banker on a straight line basis, rounding
      to the nearest month); or (ii) if such release (or any successor release) is
      not
      published during the week preceding the calculation date or does not contain
      such yields, the rate per annum equal to the semiannual equivalent yield to
      maturity of the Comparable Treasury Issue, calculated by the Independent
      Investment Banker using 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.

    


    If
      notice
      has been given as provided in the Indenture and funds for redemption of any
      Securities (or any portion thereof) called for redemption shall have been made
      available on the Redemption Date referred to in such notice, such Securities
      (or
      any portion thereof) will cease to bear interest on the date fixed for such
      redemption specified in such notice and the only right of the Holders of such
      Securities will be to receive payment of the Redemption Price.

    


    In
      the
      event of redemption of this Security in part only, a new Security or Securities
      of this Series and of like tenor for the unredeemed portion hereof will be
      issued in the name of the Holder hereof upon the cancellation
      hereof.

    


    The
      Securities of this series will not be subject to any sinking fund.

    


    If
      an
      Event of Default with respect to Securities of this series shall occur and
      be
      continuing, the principal of the Securities of this series may be declared
      due
      and payable in the manner and with the effect provided in the
      Indenture.

    


    Interest
      payments with respect to this Security will be computed and paid on the basis
      of
      a 360-day year of twelve 30-day months for the actual number of days
      elapsed.

    


    The
      Indenture permits, with certain exceptions as therein provided, the amendment
      thereof and the modification of the rights and obligations of the Company and
      the rights of the Holders of the Securities of each series to be affected under
      the Indenture at any time by the Company and the Trustee with the consent of
      the
      Holders of a majority in principal amount of the Securities at the time
      Outstanding of all series to be affected (voting as a class).  The
      Indenture also contains provisions permitting the Holders of specified
      percentages in principal amount of the Securities of each Series at the time
      Outstanding, on behalf of the Holders of all Securities of such series, to
      waive
      compliance by the Company with certain provisions of the Indenture and certain
      past defaults under the Indenture and their consequences.  Any such
      consent or waiver by the Holder of this Security shall be conclusive and binding
      upon such Holder and upon all future Holders of this Security and of any
      Security issued upon the registration of transfer hereof or in exchange herefor
      or in lieu hereof, whether or not notation of such consent or waiver is made
      upon this Security.

    


    No
      reference herein to the Indenture and no provision of this Security or of the
      Indenture shall alter or impair the obligation of the Company, which is absolute
      and unconditional, to pay the principal of, premium, if any, and interest on
      this Security at the times, place and rate, and in the coin or currency, herein
      prescribed.

    


    This
      Security shall be exchangeable for Securities registered in the names of Persons
      other than the Depositary with respect to such series or its nominee only as
      provided in the Indenture.  This Security shall be so exchangeable if
      (x) the Depositary notifies the Company that it is unwilling or unable to
      continue as Depositary for such series or at any time ceases to be a clearing
      agency registered as such under the Exchange Act, (y) the Company executes
      and
      delivers to the Trustee an Officers’ Certificate providing that this Security
      shall be so exchangeable or (z) there shall have occurred and be continuing
      an
      Event of Default with respect to the Securities of such
      series.  Securities so issued in exchange for this Security shall be
      of the same series, having the same interest rate, if any, and maturity and
      having the same terms as this Security, in authorized denominations and in
      the
      aggregate having the same principal amount as this Security and registered
      in
      such names as the Depositary for such Global Security shall direct.

    


    As
      provided in the Indenture and subject to certain limitations therein set forth,
      the transfer of a Security of the series of which this Security is a part is
      registrable in the Security Register, upon surrender of this Security for
      registration of transfer at the office or agency of the Company in any place
      where the principal of and any premium and interest on this Security are
      payable, duly endorsed by, or accompanied by a written instrument of transfer
      in
      form satisfactory to the Company and the Security Registrar duly executed by,
      the Holder hereof or his attorney duly authorized in writing, and thereupon
      one
      or more new Securities of this Series and of like tenor, of authorized
      denominations and for the same aggregate principal amount, will be issued to
      the
      designated transferee or transferees.

    


    The
      Securities of this Series are issuable only in registered form without coupons
      in denominations of $1,000 and any integral multiple thereof.  As
      provided in the Indenture and subject to certain limitations therein set forth,
      Securities of this Series are exchangeable for a like aggregate principal amount
      of Securities of this Series and of like tenor of a different authorized
      denomination, as requested by the Holder surrendering the same.

    


    No
      service charge shall be made for any such registration of transfer or exchange,
      but the Company may require payment of a sum sufficient to cover any tax or
      other governmental charge payable in connection therewith.

    


    Prior
      to
      due presentment of this Security for registration of transfer, the Company,
      the
      Trustee and any agent of the Company or the Trustee may treat the Person in
      whose name this Security is registered as the owner hereof for all purposes,
      whether or not this Security be overdue, and neither the Company, the Trustee
      nor any such agent shall be affected by notice to the contrary.

    


    For
      so
      long as this Security is issued in the form of a Global Security, any notice
      to
      be given to the Holder of this Security shall be deemed to have been duly given
      to such Holder when given to the Depositary, or its nominee, in accordance
      with
      its Applicable Procedures.  Neither the Company nor the Trustee will
      have any responsibility with respect to those policies and procedures or for
      any
      notices or other communications among the Depositary, its direct and indirect
      participants and the beneficial owners of this Security in global
      form.

     

    If
      at any
      time this Security is not represented by a Global Security, any notice to be
      given to the Holder of this Security shall be deemed to have been duly given
      to
      such Holder upon the mailing of such notice to the Holder at such Holder’s
      address as it appears on the Security Register maintained by the Company or
      its
      agent as of the close of business preceding the day such notice is
      given.

    


    Neither
      the failure to give any notice nor any defect in any notice given to the Holder
      of this Security or any other Security of this series will affect the
      sufficiency of any notice given to another Holder of any Securities of this
      series.

    


    Prior
      to
      due presentment of this Security for registration of transfer, the Company,
      the
      Trustee and any agent of the Company or the Trustee may treat the Person in
      whose name this Security is registered as the owner hereof for all purposes,
      whether or not this Security be overdue, and neither the Company, the Trustee
      nor any such agent shall be affected by notice to the contrary.

    


    The
      Indenture provides that the Company, at its option, (a) will be discharged
      from
      any and all obligations in respect of the Securities (except for certain
      obligations to register the transfer or exchange of Securities, replace stolen,
      lost or mutilated Securities, maintain paying agencies and hold moneys for
      payment in trust) or (b) need not comply with certain restrictive covenants
      of
      the Indenture, in each case if the Company deposits, in trust, with the Trustee
      money or U.S. Government Obligations which, through the payment of interest
      thereon and principal thereof in accordance with their terms, will provide
      money, in an amount sufficient to pay all the principal of, and premium, if
      any,
      and interest, if any, on the Securities on the dates such payments are due
      in
      accordance with the terms of such Securities, and certain other conditions
      are
      satisfied.

    


    No
      recourse shall be had for the payment of the principal of or the interest on
      this Security, or for any claim based hereon, or otherwise in respect hereof,
      or
      based on or in respect of the Indenture or any indenture supplemental thereto,
      against any incorporator, organizer, member, limited partner, stockholder,
      officer or director, as such, past, present or future, of the Company or any
      successor Person, whether by virtue of any constitution, statute or rule of
      law,
      or by the enforcement of any assessment or penalty or otherwise, all such
      liability being, by the acceptance hereof and as part of the consideration
      for
      the issuance hereof, expressly waived and released.

    


    This
      Security shall be governed by and construed in accordance with the laws of
      the
      State of New York without regard to principles of conflict of law except Section
      5-1401 of the New York General Obligations Law.

    


    All
      terms
      used in this Security which are defined in the Indenture shall have the meanings
      ascribed to them in the Indenture.

    


    Unless
      the certificate of authentication hereon has been executed by the Trustee
      referred to herein by manual signature, this Security shall not be entitled
      to
      any benefit under the Indenture or be valid or obligatory for any
      purpose.

    
       

       

       

    

     

    IN
      WITNESS WHEREOF, Public Service Company of Oklahoma has caused this instrument
      to be duly executed.

    


    
      	 	
              PUBLIC
                SERVICE COMPANY OF OKLAHOMA

            
	 	 	 
	 	
              By:

            	 
	 	 	
              Assistant
                Treasurer

            


    

    


    


    


    This
      is
      one of the Securities of the series designated herein and referred to in the
      within-mentioned Indenture.

    


    
      	
              Dated:  November
                14, 2007

            	
              THE
                BANK OF NEW YORK

            
	 	 	 
	 	
              By:

            	 
	 	 	
              Authorized
                Signatory

            


    

    
       

       

       

    

    


    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 TYPE NAME AND ADDRESS, INCLUDING ZIP CODE, OF

    ________________________________________________________________

    ASSIGNEE)
      the within Note and all rights thereunder, hereby

    ________________________________________________________________

    irrevocably
      constituting and appointing such person attorney to

    ________________________________________________________________

    transfer
      such Note on the books of the Issuer, 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 Note in every particular, without alteration or
      enlargement or any change whatever and NOTICE:  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”).