Exhibit
      4.1

    


    
      	
              NUMBER

              U-__________

               

            	 	 	 	
              UNITS

            
	 	 	 
	
              SEE
                REVERSE FOR CERTAIN DEFINITIONS

            	
              ALYST
                ACQUISITION CORP.

            	 


    

     

    CUSIP
      ________

    


    UNITS
      CONSISTING OF ONE SHARE OF COMMON STOCK AND ONE WARRANT EACH TO PURCHASE ONE
      SHARE OF COMMON STOCK

    
 

    THIS
      CERTIFIES THAT
      ______________________________________________________________________

    


    is
      the
      owner of
      ____________________________________________________________________________Units.

    


    Each
      Unit
      (“Unit”) consists of one (1) share of common stock, par value $.0001 per share
      (“Common Stock”), of Alyst Acquisition Corp., a Delaware corporation (the
“Company”), and one warrant (the “Warrant(s)”). Each Warrant entitles the holder
      to purchase one (1) share of Common Stock for $5.00 per share (subject to
      adjustment). Each Warrant will become exercisable on the later of (i) the
      Company’s completion of a merger, capital stock exchange, asset acquisition or
      other similar business combination and (ii) ___________, 2008, and will expire
      unless exercised before 5:00 p.m., New York City Time, on ____________, 2011,
      or
      earlier upon redemption (the “Expiration Date”). The Common Stock and Warrants
      comprising the Units represented by this certificate are not transferable
      separately prior to __________, 2008, subject to earlier separation in the
      discretion of Jesup & Lamont Securities Corporation. The terms of
      the Warrants are governed by a Warrant Agreement, dated as of _______, 2007,
      between the Company and Continental Stock Transfer & Trust Company, as
      Warrant Agent, and are subject to the terms and provisions contained therein,
      all of which terms and provisions the holder of this certificate consents to
      by
      acceptance hereof. Copies of the Warrant Agreement are on file at the office
      of
      the Warrant Agent at 17 Battery Place, New York, New York 10004, and are
      available to any Warrant holder on written request and without cost.


     

    This
      certificate is not valid unless countersigned by the Transfer Agent and
      Registrar of the Company.

     

    Witness
      the facsimile seal of the Company and the facsimile signatures of its duly
      authorized officers.

    


    


    
      	
               

            	
               

            	 	 	 	 
	 

              By

            	 	
               

            	 
	 	 	 	 	 	 
	 	
              Chairman of
                the Board

            	 	 	
              Secretary
                

            


    

           


    
      
        
           

        

        
        

      

      
        
        

        
          

        

      

      
        
        

        
        

      

    



    Alyst
      Acquisition Corp.

     

    The
      Company will furnish without charge to each stockholder who so requests, a
      statement of the powers, designations, preferences and relative, participating,
      optional or other special rights of each class of stock or series thereof of
      the
      Company and the qualifications, limitations, or restrictions of such preferences
      and/or rights. 

     

    The
      following abbreviations, when used in the inscription on the face of this
      certificate, 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
                ______

            
	
               TEN ENT -  as
                tenants by the entireties

            	 	
                  (Cust)  
                (Minor)

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

            	 	
                under
                Uniform Gifts to
                Minors

            
	 	 	 	
                 
                Act ______________

            
	 	 	 	
                   
(State)

            

                           

    


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

     

    For
      value received, ___________________________ hereby sell, assign and transfer
      unto

    


    PLEASE
      INSERT SOCIAL SECURITY OR OTHER

    IDENTIFYING
      NUMBER OF ASSIGNEE

    
      	 	 	 	 
	 	 	 	 
	 	 	 	 
	 	 	 	 
	 
	
               (PLEASE
                PRINT OR TYPEWRITE NAME AND
                ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE)

            
	 	 	 	 
	 
	 
	 	Units
	 	 	 	 
	represented by the
              within
              Certificate, and do hereby irrevocably constitute and
              appoint
	 	 Attorney
	 	 	 	 


    

    to
      transfer the said Units on the books of the within named Company will 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 certificate in every particular, without alteration
                or
                enlargement or any change whatever.

            


    

    


    Signature(s)
      Guaranteed:

    


    
      
        	 	 
	
                THE
                  SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR
                  INSTITUTION

                (BANKS,
                  STOCKBROKERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS
                  WITH

                MEMBERSHIP
                  IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM, PURSUANT
                  

                TO
                  S.E.C. RULE 17Ad-15).