Enzymatic Joining of Polynucleotides

Polydeoxythymidylatein which the 5'-terminal phosphate is linked by a pyrophosphate bond to adenosine 5'-phosphate (poly dT-adenylate) serves as an intermediate in the reactions catalyzed by the Escherichia coli and T4-induced polynucleotide joining enzymes in the presence of polydeoxyadenylate.Adenosine 5'-phosphate release and phosphodiester bond formation occur stoichiometrically and with the same time course.The reaction is inhibited by DPN; hence it may be inferred that enzyme-adenylate is inactive in the reaction.The Km of the E. coli joining enzyme for poly dT-adenylate is 1 to 3 PM; the Km for poly dT is 0.003