PRPP
PRPP, or 5-phosphoribosyl-1-pyrophosphate, is a highly activated form of ribose phosphate that serves as a donor of the ribose-5-phosphate moiety in nucleotide metabolism. It is produced from ribose-5-phosphate by the enzyme ribose-phosphate pyrophosphokinase (also called PRPP synthetase), using ATP and yielding PRPP and AMP.
In de novo purine biosynthesis, PRPP provides the prime substrate for the enzyme glutamine-PRPP amidotransferase, which
PRPP also participates in salvage pathways that recycle bases into nucleotides. Hypoxanthine and guanine are converted
Regulation and clinical relevance: PRPP levels are tightly controlled to balance nucleotide synthesis with cellular energy