The enzyme (HPRT1, hypoxanthine-guanine phosphoribosyl transferase, EC 18.104.22.168, 218 aa) that catalyses the conversion of hypoxanthine to inosine monophosphate and guanine to guanosine monophosphate as the first step in the purine salvage pathway. Normal cells can synthesize purines de novo, and are not totally dependent on the salvage pathway, but HGPRT-mutant cells are resistant to toxic purine analogues, which can be used as a basis for selection. See HAT medium. Mutation in the gene for HGPRT is responsible for Lesch–Nyhan syndrome.
Subjects: Medicine and Health.