In enzymology, an inosine nucleosidase () is an enzyme that catalyzes the chemical reaction inosine + H2O D-ribose + hypoxanthine Thus, the two substrates of this enzyme are inosine and H2O, whereas its two products are D-ribose and hypoxanthine. This enzyme belongs to the family of hydrolases, specifically those glycosylases that hydrolyse N-glycosyl compounds. The systematic name of this enzyme class is inosine ribohydrolase. Other names in common use include inosinase, and inosine-guanosine nucleosidase. This enzyme participates in purine metabolism. References EC 3.2.2 Enzymes of unknown structure