Purine nucleoside phosphorylase

Purine nucleoside phosphorylase ( PNP) (Gen: NP ) is the one enzyme that removes the ribose of ribonucleic and deoxyribonucleic purine nucleosides. It is indispensable for reducing these basic building blocks of genetic information in all living things ( via corresponding enzymes in plants, however, is not yet known ). The PNP is localized in the cytosol. Mutations of the NP gene in humans can cause hereditary PNP deficiency, which is associated in childhood with severe T -cell immunodeficiency.

The active form of human PNP is a trimer with a molecular weight of about 100 kDa. PNP is responsible for the degradation of deoxyribonucleosides ( deoxyguanosine to guanine, adenine, and deoxyadenosine to deoxyinosine to hypoxanthine ) and ribonucleosides ( inosine to hypoxanthine, guanosine, xanthosine to xanthine and to guanine ). In each case one molecule of 2 -deoxyribose -1-phosphate or ribose -1-phosphate is produced.

Disturbances in purine metabolism lead to severe metabolic disorders. Have defects of the PNP for example, a strong reduction of T lymphocytes in the blood ( lymphopenia ) and neurological disorders ( mental retardation ) result.

Human Genome Organisation Glycosyltransferase Genome Human (disambiguation)
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