EC - 5-(carboxyamino)imidazole ribonucleotide synthase

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IntEnz Enzyme Nomenclature


Accepted name:
5-(carboxyamino)imidazole ribonucleotide synthase
Other names:
N5-CAIR synthetase
N5-carboxyaminoimidazole ribonucleotide synthetase
Systematic name:
5-amino-1-(5-phospho-D-ribosyl)imidazole:carbon-dioxide ligase (ADP-forming)



In Escherichia coli, this enzyme, along with EC, 5-(carboxyamino)imidazole ribonucleotide mutase, is required to carry out the single reaction catalysed by EC, phosphoribosylaminoimidazole carboxylase, in vertebrates. Belongs to the ATP grasp protein superfamily [3]. Carboxyphosphate is the putative acyl phosphate intermediate. Involved in the late stages of purine biosynthesis.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , DIAGRAM , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0034028
UniProtKB/Swiss-Prot: (29) [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. Thoden, J.B., Kappock, T.J., Stubbe, J. and Holden, H.M.
    Three-dimensional structure of N5-carboxyaminoimidazole ribonucleotide synthetase: a member of the ATP grasp protein superfamily.
    Biochemistry 38: 15480-15492 (1999). [PMID: 10569930]

[EC created 2006]