PNP

PNP is an enzyme which reversibly catalyzes the phosphorolysis of purine nucleosides. The enzyme is trimeric, containing three identical subunits. Mutations which result in nucleoside phosphorylase deficiency result in defective T-cell (cell-mediated) immunity but can also affect B-cell immunity and antibody responses. Neurologic disorders may also be apparent in patients with immune defects.

Purine Nucleoside Phosphorylase

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:9305964, PubMed:23438750).
Preferentially acts on 6-oxopurine nucleosides including inosine and guanosine (PubMed:9305964).

Allantoin metabolic processManual Assertion Based On ExperimentIDA:MGI
dAMP catabolic processManual Assertion Based On ExperimentIDA:MGI
Deoxyadenosine catabolic processManual Assertion Based On ExperimentIDA:MGI
Deoxyinosine catabolic processManual Assertion Based On ExperimentIDA:MGI
Immune responseManual Assertion Based On ExperimentIMP:UniProtKB
IMP catabolic processManual Assertion Based On ExperimentIDA:MGI
Inosine catabolic processManual Assertion Based On ExperimentIDA:UniProtKB
Nicotinamide riboside catabolic processManual Assertion Based On ExperimentIDA:UniProtKB
Nucleobase-containing compound metabolic processManual Assertion Based On ExperimentIDA:UniProtKB
Nucleotide biosynthetic processManual Assertion Based On ExperimentIGI:UniProtKB
Positive regulation of alpha-beta T cell differentiationManual Assertion Based On ExperimentIDA:MGI
Positive regulation of interleukin-2 productionManual Assertion Based On ExperimentIMP:UniProtKB
Positive regulation of T cell proliferationManual Assertion Based On ExperimentIDA:MGI
Purine ribonucleoside salvageIEA:UniProtKB-KW
Purine-containing compound salvageManual Assertion Based On ExperimentIDA:UniProtKB
Response to xenobiotic stimulusManual Assertion Based On ExperimentIMP:UniProtKB
Urate biosynthetic processManual Assertion Based On ExperimentIDA:MGI

Cytoplasm

Purine nucleoside phosphorylase deficiency (PNPD):
A disorder that interrupts both the catabolism of inosine into hypoxanthine and guanosine into guanine, and leads to the accumulation of guanosine, inosine, and their deoxified by-products. The main clinical presentation is recurrent infections due to severe T-cell immunodeficiency. Some patients also have neurologic impairment.