PRPP

(noun)

Phosphoribosyl pyrophosphate (PRPP) is a pentosephosphate formed from ribose 5-phosphate by the enzyme ribose-phosphate diphosphokinase. It plays a role in transferring phospho-ribose groups in several reactions:

Related Terms

Examples of PRPP in the following topics:

  • Purine and Pyrimidine Synthesis

    • A key regulatory step is the production of 5-phospho-α-D-ribosyl 1-pyrophosphate (PRPP) by PRPP synthetase, which is activated by inorganic phosphate and inactivated by purine ribonucleotides.
    • It is not a committed step to purine synthesis because PRPP is also used in pyrimidine synthesis and salvage pathways.
    • The first committed step is the reaction of PRPP, glutamine and water to 5'-phosphoribosylamine, glutamate, and pyrophosphate - catalyzed by pyrophosphate amidotransferase, which is activated by PRPP and inhibited by AMP, GMP and IMP.
    • Unlike purines, pyrimidines are assembled before being attached to 5-phosphoribosyl-1-pyrophosphate (PRPP).