Hypoxanthine-guanine phosphoribosyltransferase (HPRT) is an enzyme () in purine metabolism. It converts hypoxanthine to inosine monophosphate,and in some species, guanine to guanine monophosphate (often renamed as HGPRT). Certain HPRTs can also convert xanthine to xanthine monophosphate.

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.

Genetics

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HPRT is located on the X chromosome (Xq26-q27.2).

Role in disease

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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.

External link

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• Purine metabolism

EC 2.4.2