Biochemistry · Enzyme
PRPP synthetase !
Makes PRPP, the activated ribose needed to build and recycle every nucleotide.
Updated 2026-11-01
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Key facts
- Ribose-5-phosphate + ATP → PRPP + AMP, with Mg²⁺ and inorganic phosphate as activator.
- Its substrate comes from the pentose phosphate pathway.
- The PRPS1 gene is on the X chromosome: superactivity mainly affects males.
- Loss-of-function mutations cause a different picture: deafness, neuropathy or Arts syndrome.
Regulation
- ADP and GDP inhibit it (nucleotide feedback).
- Inorganic phosphate activates it.
Inhibitors and toxins
- ADP and GDP (physiological)
Clinical notes
- PRPP synthetase superactivity: more PRPP, more purine synthesis, gout and uric acid stones in youth.
- The severe form of superactivity comes with deafness and developmental delay from infancy.
Pathways
Related conditions
Related
- PRPP (phosphoribosyl pyrophosphate)
- Glutamine-PRPP amidotransferase
- Hypoxanthine-guanine phosphoribosyltransferase (HGPRT)
- UMP synthase
Test yourself
Think of the answer, then tap the question to see it.
What does PRPP synthetase make, and what is it used for?
PRPP: it feeds de novo purine and pyrimidine synthesis, base salvage and NAD⁺ synthesis.
Why does PRPP synthetase superactivity cause gout?
Extra PRPP drives the amidotransferase and purine synthesis, which end up as uric acid.
How is PRPP synthetase superactivity inherited?
X-linked (PRPS1 gene): it mainly affects males.
Educational information, not medical advice. For any symptom, see a health professional.
Sources: PRPS1: Ribose-phosphate pyrophosphokinase 1 (human) (UniProt, 2026); Phosphoribosylpyrophosphate synthetase superactivity: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2026); PRPS1 gene: MedlinePlus Genetics (MedlinePlus, US National Library of Medicine, 2026); 2HCR: crystal structure of human phosphoribosyl pyrophosphate synthetase 1 in complex with AMP(ATP), cadmium and sulfate ion (RCSB Protein Data Bank, 2026).
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Representative model, for educational purposes only.