EC - 5-(carboxyamino)imidazole ribonucleotide mutase

  IntEnz view ENZYME view

IntEnz Enzyme Nomenclature


Accepted name:
5-(carboxyamino)imidazole ribonucleotide mutase
Other names:
N5-CAIR mutase
N5-carboxyaminoimidazole ribonucleotide mutase
class I PurE
Systematic name:
5-carboxyamino-1-(5-phospho-D-ribosyl)imidazole carboxymutase



In eubacteria, fungi and plants, this enzyme, along with EC, 5-(carboxyamino)imidazole ribonucleotide synthase, is required to carry out the single reaction catalysed by EC, phosphoribosylaminoimidazole carboxylase, in vertebrates [6]. In the absence of EC, phosphoribosylaminoimidazolesuccinocarboxamide synthase, the reaction is reversible [3]. The substrate is readily converted into 5-amino-1-(5-phospho-D-ribosyl)imidazole by non-enzymic decarboxylation [3].

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0034023
CAS Registry Number: 255379-40-9
UniProtKB/Swiss-Prot: (25) [show] [UniProt]


  1. Meyer, E., Leonard, N.J., Bhat, B., Stubbe, J. and Smith, J.M.
    Purification and characterization of the purE, purK, and purC gene products: identification of a previously unrecognized energy requirement in the purine biosynthetic pathway.
    Biochemistry 31: 5022-5032 (1992). [PMID: 1534690]
  2. Mueller, E.J., Meyer, E., Rudolph, J., Davisson, V.J. and Stubbe, J.
    N5-carboxyaminoimidazole ribonucleotide: evidence for a new intermediate and two new enzymatic activities in the de novo purine biosynthetic pathway of Escherichia coli.
    Biochemistry 33: 2269-2278 (1994). [PMID: 8117684]
  3. Meyer, E., Kappock, T. J., Osuji, C. and Stubbe, J.
    Evidence for the direct transfer of the carboxylate of N5-carboxyaminoimidazole ribonucleotide (N5-CAIR) to generate 4-carboxy-5-aminoimidazole ribonucleotide catalyzed by Escherichia coli PurE, an N5-CAIR mutase.
    Biochemistry 38: 3012-3018 (1999). [PMID: 10074353]
  4. Mathews, I.I., Kappock, T.J., Stubbe, J. and Ealick, S.E.
    Crystal structure of Escherichia coli PurE, an unusual mutase in the purine biosynthetic pathway.
    Structure 7: 1395-1406 (1999). [PMID: 10574791]
  5. Firestine, S.M., Poon, S.-W., Mueller, E.J., Stubbe, J. and Davisson, V.J.
    Reactions catalyzed by 5-aminoimidazole ribonucleotide carboxylases from Escherichia coli and Gallus gallus: a case for divergent catalytic mechanisms.
    Biochemistry 33: 11927-11934 (1994). [PMID: 7918411]
  6. Firestine, S.M., Misialek, S., Toffaletti, D.L., Klem, T.J., Perfect, J.R. and Davisson, V.J.
    Biochemical role of the Cryptococcus neoformans ADE2 protein in fungal de novo purine biosynthesis.
    Arch. Biochem. Biophys. 351: 123-134 (1998). [PMID: 9500840]

[EC created 2006]