Ribonuclease and oigoribonucleotide synthesis. II. Synthesis of oligonucleotides of specific sequence.

Ribonuclease A and ribonuclease S-protein have been investigated for their ability to catalyze the preparative synthesis of dinucleoside monophosphates and trinucleoside diphosphates of specific base composition and sequence. Kinetic analysis of identical reactions catalyzed by ribonuclease A and S-protein suggests that the synthetic activity of the native protein and the derivative differ with respect to rate constant, Km, and the effect of a nucleoside acceptor. Ribonuclease A has been used to prepare dinucleoside monophosphates and trinucleoside diphosphates of specific sequence by the reaction of pyrimidine 2’,3’-cyclic nucleotides with a nucleoside. S-Protein has been used to prepare trinucleoside diphosphates of specific sequence by the reaction of a pyrimidine 2’,3’-cyclic nucleotide with a dinucleoside monophosphate. Twenty-five trinucleoside diphosphates and four dinucleoside monophosphates have been synthesized. Isolation and purification procedures yielded products free from contaminating materials, sequence isomers, and 2’,5’-phosphodiester linkages. Representative compounds were characterized by chromatographic, electrophoretic, base ratio, and sequence analyses.