Phosphoribosyl pyrophosphate (PRPP) is a crucial molecule in cellular metabolism, primarily involved in the synthesis of nucleotides and nucleic acids. It is formed from ribose-5-phosphate and ATP through the action of the enzyme PRPP synthetase. PRPP serves as a ribose donor in the formation of purines and pyrimidines, which are essential components of DNA and RNA. In addition to its role in nucleotide synthesis, PRPP is also involved in the biosynthesis of tryptophan and histidine, two important amino acids. The regulation of PRPP levels is vital for maintaining proper cellular function and ensuring balanced metabolic pathways.