Phosphoribosyl pyrophosphate

Phosphoribosyl pyrophosphate (PRPP) is a pentosephosphate.
It is formed from ribose 5-phosphate by the enzyme ribose-phosphate diphosphokinase.
It plays a role in transferring phospho-ribose groups in several reactions:
In "de novo" generation of purines, the enzyme amidophosphoribosyltransferase acts upon PRPP to create phosphoribosylamine.
Increased PRPP.
Increased levels of PRPP is characterized by the overproduction and accumulation of uric acid leading to hyperuricemia and hyperuricosuria. It is one of the causes of gout.
Increased levels of PRPP are present in Lesch–Nyhan Syndrome. Decreased levels of hypoxanthine guanine phosphoribosyl transferase (HGPRT) causes this accumulation, as PRPP is a substrate used by HGPRT during purine salvage.