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. The vitamins thiamine and cobalamin also contain fragments derived from PRA.

Phosphoribosylamine
Names
Other names
PRA
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
MeSH Phosphoribosylamine
  • 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
  • C([C@@H]1[C@H]([C@H](C(O1)N)O)O)OP(=O)(O)O
Properties
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:

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:

PRA + glycine + ATP → GAR + ADP + Pi
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