Purine nucleoside phosphorylase

Purine nucleoside phosphorylase (also known as PNPase) is an enzyme involved in purine metabolism. PNP metabolizes adenosine into adenine, inosine into hypoxanthine, and guanosine into guanine, in each case creating ribose phosphate.

Confusingly, the same abbreviation (PNPase), is also used for another, otherwise unrelated, enzyme, namely Polynucleotide Phosphorylase.

Diseases linked to PNP: PNP deficient patients will have an immunodeficiency problem. Curiously, it affects only T-cells, B-cells are unaffected by the deficiency.