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Phosphoribosyl pyrophosphate (PRPP) is a pentosephosphate.

Phosphoribosyl pyrophosphate
Phosphoribosyl pyrophosphate.svg
Other names
5-phospho-alpha-D-ribose 1-diphosphate
3D model (JSmol)
MeSH Phosphoribosyl+pyrophosphate
Molar mass 390.07 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

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:

Enzyme Reactant Product
adenine phosphoribosyltransferase adenine AMP
hypoxanthine-guanine phosphoribosyltransferase guanine GMP
hypoxanthine-guanine phosphoribosyltransferase hypoxanthine IMP
orotate phosphoribosyltransferase orotate OMP
uracil phosphoribosyltransferase uracil UMP

In de novo generation of purines, the enzyme amidophosphoribosyltransferase acts upon PRPP to create phosphoribosylamine.

Increased PRPPEdit

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.

See alsoEdit