Ribosyl and Deoxyribosyl Transfer by Bacterial Enzyme Systems

Abstract

The enzymatic transfer of ribose and deoxyribose residues in pyrimidine nucleosides to purines was catalyzed by cell-free extracts of various bacteria. Almost all the strains belonging to Entero-bacteriaceae were capable of catalyzing the transfer reactions. The transfer activities were also detected among some bacterial strains of other families: Pseudomonadaceae, Corynebacteriaceae, Micrococ-caceae, Bacteriaceae and Bacillaceae. The rates of the transfer reactions were greantly enhanced in the presence of phosphate ion, and the participation of nucleoside phosphorylases in the reactions was suggested. Uridine phosphorylase, thymidine phosphorylase, and purine nucleoside phosphorylase were purified from cell-free extract of Aerobacter aerogenes IFO 3321. The ribosyl transfer from uridine to hypoxanthine was catalyzed by the coupled reactions of uridine and purine nucleoside phosphorylases and the deoxyribosyl transfer from thymidine to hypoxanthine by the coupled reactions of thymidine and purine nucleoside phosphorylases.