Ribosidases

Nucleotide-N-ribosidase is discussed by Schlenk (ref. 194, p. 508). There is doubt that the ribosidic bond of nucleotides can be enzymatically hydrolyzed. 

Cleavage of the iV-glycosidic bond of nucleomdes may also be effected by nucleoside hydrolase ( ribosidase ) according to the following reaction ... 

A nucleotide hydrolase, adenylic acid ribosidase, has been found in Azotobacter vinelandii which carries out the following reaction ... 

A pyridine ribosidase from Xanthomonas pruni has been described which splits nicotmamide riboside in preference to purine ribosides (18 ). The relative activity towards nicotinamide riboside and inosine is about 30 to 1. In contrast to this, extracts of SaccJiaromyces cereviaiae promote the hydroljrtic cleavage of nicotinamide riboside and inosine at approximately the same rate (183). A hydrolytic nucleoadase from a strain of Lactobacillus delbruckii has been purified and also shown to have equal activity towards the two nucleosides (184). Xanthomonas pyridine nucleosidase appears to be unusual for bacteria its significance is not clear as yet. 

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