IUBMB Enzyme Nomenclature


Accepted name: adenosylcobyric acid synthase (glutamine-hydrolysing)

Reaction: 4 ATP + adenosylcobyrinic acid a,c-diamide + 4 L-glutamine + 4 H2O = 4 ADP + 4 phosphate + adenosylcobyric acid + 4 L-glutamate

For diagram click here.

Other name(s): CobQ; cobyric acid synthase; 5'-deoxy-5'-adenosylcobyrinic-acid-a,c-diamide:L-glutamine amido-ligase; Ado-cobyric acid synthase [glutamine hydrolyzing]

Systematic name: adenosylcobyrinic-acid-a,c-diamide:L-glutamine amido-ligase (ADP-forming)

Comments: Requires Mg2+. NH3 can act instead of glutamine. This enzyme catalyses the four-step amidation sequence from cobyrinic acid a,c-diamide to cobyric acid via the formation of cobyrinic acid triamide, tetraamide and pentaamide intermediates.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 137672-90-3


1. Blanche, F., Couder, M., Debussche, L., Thibaut, D., Cameron, B. and Crouzet, J. Biosynthesis of vitamin B12: stepwise amidation of carboxyl groups b, d, e, and g of cobyrinic acid a,c-diamide is catalyzed by one enzyme in Pseudomonas denitrificans. J. Bacteriol. 173 (1991) 6046-6051. [PMID: 1917839]

2. Warren, M.J., Raux, E., Schubert, H.L. and Escalante-Semerena, J.C. The biosynthesis of adenosylcobalamin (vitamin B12). Nat. Prod. Rep. 19 (2002) 390-412. [PMID: 12195810]

[EC created 2004]

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