EC - Cobyrinate a,c-diamide synthase (glutamine-hydrolysing)

  IntEnz view ENZYME view

IntEnz Enzyme Nomenclature


Accepted name:
cobyrinate a,c-diamide synthase (glutamine-hydrolysing)
Other names:
cobyrinic acid a,c-diamide synthetase
Systematic name:
cobyrinate:L-glutamine amido-ligase (ADP-forming)



This enzyme is the first glutamine amidotransferase that participates in the anaerobic (early cobalt insertion) biosynthetic pathway of adenosylcobalamin, and catalyses the ATP-dependent synthesis of cobyrinate a,c-diamide from cobyrinate using either L-glutamine or ammonia as the nitrogen source. It is proposed that the enzyme first catalyses the amidation of the c-carboxylate, and then the intermediate is released into solution and binds to the same catalytic site for the amidation of the a-carboxylate. The Km for ammonia is substantially higher than that for L-glutamine.

Links to other databases

Enzymes and pathways: NC-IUBMB , BRENDA , ExplorEnz , ENZYME@ExPASy , KEGG , MetaCyc , UniPathway
Structural data: CSA , EC2PDB
Gene Ontology: GO:0043775 , GO:0042242
UniProtKB/Swiss-Prot: (42) [show] [UniProt]


  1. Fresquet, V., Williams, L., Raushel, F. M.
    Mechanism of cobyrinic acid a,c-diamide synthetase from Salmonella typhimurium LT2.
    Biochemistry 43: 10619-10627 (2004). [PMID: 15311923]

[EC created 2010]