Hypoxanthine-guanine phosphoribosyltransferase

Hypoxanthine-guanine phosphoribosyltransferase (HPRT ) is an enzyme in purine metabolism.

Functions
It catalyzes the following reactions:

The enzyme primarily functions to salvage purines from degraded DNA to renewed purine synthesis. In this role, it acts as a catalyst in the reaction between guanine and phosphoribosyl pyrophosphate (PRPP) to form GMP.

B cells contain this enzyme which enables them to survive when fused to myeloma cells when grown on HAT medium to produce monoclonal antibodies.

Role in disease
Mutations in the gene lead to hyperuricemia:
 * Lesch-Nyhan syndrome is due to HPRT mutations.
 * Some mutations have been linked to gout, the risk of which is increased in hyperuricemia.