Heteropolydeoxynucleotides Synthesized with Terminal Deoxyribonucleotidyltransferase

The nature and relative amounts of the pyrimidine nucleotide sequences which occur in heteropolydeoxynucleotides synthesized with terminal deoxyribonucleotidyltransferase have been determined for the limited class of products containing a single pyrimidine moiety and one or more purine types by the use of acid degradation followed by ion exchange chromatography. The results offer further proof that, in these products, the synthetic reaction is a true copolymerization and that no recognizable order in the sequences is present. The lengths and frequencies of sequences of repeated pyrimidine nucleotide residues in the various copolymers appear to be influenced by the identity of the purine nucleoside triphosphates present during the copolymerization, as well as to the stoichiometry of the reaction mixture.