Purine Nucleoside Phosphorylase Inhibitor

**Semantic type:** Chemical Viewed Functionally

**Definition:** Any substance that inhibits purine nucleoside phosphorylase, an enzyme involved in the purine salvage pathway that metabolizes adenosine into adenine, inosine into hypoxanthine, and guanosine into guanine. Inhibition of purine nucleoside phosphorylase results in accumulation of dGTP and the subsequent failure of DNA synthesis, with its greatest effect in T-cells.