PRPP is an intermediate in nucleotide metabolism. It is found in several de novo and salvage pathways. PRPP is formed by action of the enzyme, PRPP Synthetase, as follows:
ATP + Ribose-5-Phosphate <=> PRPP + AMP
Enzymes that act on PRPP include Phosphoribosyltransferases (salvage synthesis and de novo synthesis of pyrimidines), PRPP amidotransferase (de novo purine synthesis)
See also: De Novo Biosynthesis of Purine Nucleotides, De Novo Pyrimidine Nucleotide Metabolism, Nucleotide Salvage Synthesis