title: [Purine nucleoside phosphorylase (PNP)].
abstract: PNP, encoded by 6 exons on human chromosome 14q13, is a homotrimetic enzyme of approximately 96 k dalton. This enzyme reversibly catalyzes the phosphorolysis of purine nucleoside to their respective purine bases and the corresponding pentose-1-phosphate. The ultimate degradative product of purine nucleoside is uric acid, which is a depleted product with the absence of PNP activity. This leads to accumulation of deoxy-guanosine triphosphate, which inhibits the enzyme ribonucleoside reductase resulting in DNA synthesis block and T cell proliferation. Basic and brief knowledge of PNP biochemistry and functional physiology is summarized for the understanding of clinical features of PNP deficiency.
authors.affiliation: Department of 1st Pathology, St. Marianna University School of Medicine.
authors.forename: T
authors.initials: T
authors.lastname: Sakiyama
mesh_terms: D000818:Animals; D004247:DNA / Q000096:biosynthesis; D003848:Deoxyguanine Nucleotides / Q000378:metabolism / Q000502:physiology; D006160:Guanosine Triphosphate / Q000378:metabolism; D006801:Humans; D008213:Lymphocyte Activation; D011684:Purine Nucleosides / Q000378:metabolism; D011683:Purine-Nucleoside Phosphorylase / Q000172:deficiency / Q000502:physiology; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D003848:Deoxyguanine Nucleotides; D011684:Purine Nucleosides; D006160:Guanosine Triphosphate; C029603:deoxyguanosine triphosphate; D004247:DNA; D011683:Purine-Nucleoside Phosphorylase