Phosphoribosyl pyrophosphate

Phosphoribosyl pyrophosphate (PRPP) is a pentose phosphate. It is a biochemical intermediate in the formation of purine nucleotides via inosine-5-monophosphate, as well as in pyrimidine nucleotide formation. Hence it is a building block for DNA and RNA. The vitamins thiamine and cobalamin, and the amino acid tryptophan also contain fragments derived from PRPP. It is formed from ribose 5-phosphate (R5P) by the enzyme ribose-phosphate diphosphokinase:

"PRPP" redirects here. Not to be confused with Pooled Retirement Pension Plan.
Phosphoribosyl pyrophosphate
Names
IUPAC name
α-D-Ribofuranose 1′-(trihydrogen diphosphate) 5′-(dihydrogen phosphate)
Systematic IUPAC name
(2R,3R,4S,5R)-3,4-Dihydroxy-5-[(phosphonooxy)methyl]oxolan-2-yl trihydrogen diphosphate
Other names
5-phospho-α-D-ribose 1-diphosphate
PRPP
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
DrugBank
MeSH Phosphoribosyl+pyrophosphate
UNII
  • InChI=1S/C5H13O14P3/c6-3-2(1-16-20(8,9)10)17-5(4(3)7)18-22(14,15)19-21(11,12)13/h2-7H,1H2,(H,14,15)(H2,8,9,10)(H2,11,12,13)/t2-,3-,4-,5-/m1/s1 Y
    Key: PQGCEDQWHSBAJP-TXICZTDVSA-N Y
  • InChI=1/C5H13O14P3/c6-3-2(1-16-20(8,9)10)17-5(4(3)7)18-22(14,15)19-21(11,12)13/h2-7H,1H2,(H,14,15)(H2,8,9,10)(H2,11,12,13)/t2-,3-,4-,5-/m1/s1
    Key: PQGCEDQWHSBAJP-TXICZTDVBW
  • O=P(O[C@H]1O[C@@H]([C@@H](O)[C@H]1O)COP(=O)(O)O)(O)OP(=O)(O)O
Properties
C5H13O14P3
Molar mass 390.07 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

It plays a role in transferring phospho-ribose groups in several reactions, some of which are salvage pathways:

EnzymeReactantProduct
adenine phosphoribosyltransferaseadenineAMP
hypoxanthine-guanine phosphoribosyltransferaseguanineGMP
hypoxanthine-guanine phosphoribosyltransferasehypoxanthineIMP
nicotinate phosphoribosyltransferasenicotinatenicotinate riboside
orotate phosphoribosyltransferaseorotateOMP
uracil phosphoribosyltransferaseuracilUMP
xanthine phosphoribosyltransferasexanthineXMP

In de novo generation of purines, the enzyme amidophosphoribosyltransferase acts upon PRPP to create phosphoribosylamine. The histidine biosynthesis pathway involves the reaction between PRPP and ATP, which activates the latter to ring cleavage. Carbon atoms from ribose in PRPP form the linear chain and part of the imidazole ring in histidine. The same is true for the biosynthesis of tryptophan, with the first step being N-alkylation of anthranilic acid catalysed by the enzyme anthranilate phosphoribosyltransferase.

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