Phosphoribosylamine

Phosphoribosylamine (PRA) is a biochemical intermediate in the formation of purine nucleotides via inosine-5-monophosphate, and hence is a building block for DNA and RNA.^[1][2][3] The vitamins thiamine^[4] and cobalamin^[5] also contain fragments derived from PRA.^[6]

Phosphoribosyl pyrophosphate (PRPP)

Phosphoribosylamine

Names
Other names PRA
Identifiers
CAS Number	14050-66-9 Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:17284
ChemSpider	2339538 Y
MeSH	Phosphoribosylamine
PubChem CID	3082052
CompTox Dashboard (EPA)	DTXSID10903977
InChI InChI=1S/C5H12NO7P/c6-5-4(8)3(7)2(13-5)1-12-14(9,10)11/h2-5,7-8H,1,6H2,(H2,9,10,11)/t2-,3-,4-,5?/m1/s1 Y Key: SKCBPEVYGOQGJN-SOOFDHNKSA-N Y
SMILES C([C@@H]1[C@H]([C@H](C(O1)N)O)O)OP(=O)(O)O
Properties
Chemical formula	C5H12NO7P
Molar mass	229.125 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 is the product of the enzyme amidophosphoribosyltransferase which attaches ammonia from glutamine to phosphoribosyl pyrophosphate (PRPP) at its anomeric carbon:^[2]

PRPP + glutamine → PRA + glutamate + PPi

The biosynthesis pathway next combines PRA with glycine in a process driven by ATP giving glycineamide ribonucleotide (GAR). The enzyme phosphoribosylamine—glycine ligase catalyses the reaction forming an amide bond:^[7]

PRA + glycine + ATP → GAR + ADP + Pi

See also

• 5-Aminoimidazole ribotide
• Purine metabolism