Purine nucleoside phosphorylase

UniProtKB accession:  Q8I3X4

Grouped By:  Matching UniProtKB accession

UniProtKB description:  As part of the purine salvage pathway, catalyzes the phosphorolytic breakdown of the N-glycosidic bond in the beta-(deoxy)ribonucleoside molecules, with the formation of the corresponding free purine bases and pentose-1-phosphate (PubMed:14982926, PubMed:16131758, PubMed:18957439, PubMed:19575810, PubMed:24416224, PubMed:29440412). Preferentially acts on inosine and guanosine, and to a lesser extent on 2'-deoxyguanosine and guanosine (PubMed:14982926, PubMed:16131758, PubMed:19575810). Also catalyzes the phosphorylation of S-methyl-5'-thioinosine (MTI) to hypoxanthine; MTI is produced by adenosine deaminase (ADA)-mediated breakdown of S-methyl-5'-thioadenosine (MTA), a major by-product of polyamine biosynthesis (PubMed:14982926, PubMed:18957439, PubMed:24416224). Generates hypoxanthine from both the purine salvage pathway and from polyamine metabolism which is required for nucleic acids synthesis (PubMed:14982926, PubMed:18957439, PubMed:24416224). Has no activity towards adenosine (By similarity).