Purine nucleoside phosphorylase (DeoD-type) (PNP)

Purine nucleoside phosphorylase (DeoD-type) from Escherichia coli is a hexameric enzyme (EC 2.4.2.1) that catalyzes the reversible phosphorolysis of purine ribonucleosides and 2′-deoxypurine nucleosides, yielding free purine bases and ribose 1-phosphate[1][3][4]. It plays a critical role in the purine salvage pathway, providing essential bases for DNA and RNA synthesis[1][4]. E. coli PNP is structurally and mechanistically distinct from mammalian PNPs; while both catalyze similar reactions, E. coli PNP is a hexamer with broader substrate specificity, unlike the trimeric mammalian enzymes[3]. This difference is harnessed in gene therapy strategies, where E. coli PNP can activate specific prodrugs that are inert to mammalian PNP, conferring selectivity for cells expressing the bacterial enzyme[3]. Acyclovir, an antiviral agent, is a known substrate analog for structural studies[1].

Other names

Purine nucleoside phosphorylasePNPDeoD

Catalyzes phosphorolysis of N-glycosidic bond in purine (deoxy)ribonucleosides using orthophosphate, yielding free purine bases and (deoxy)ribose-1-phosphate[1][2][3][4]