Accepted name: hydrogenobyrinic acid a,c-diamide synthase (glutamine-hydrolysing)
Reaction: 2 ATP + hydrogenobyrinic acid + 2 L-glutamine + 2 H2O = 2 ADP + 2 phosphate + hydrogenobyrinic acid a,c-diamide + 2 L-glutamate
Other name(s): CobB
Systematic name: hydrogenobyrinic-acid:L-glutamine amido-ligase (AMP-forming)
Comments: This enzyme, which participates in the aerobic (late cobalt insertion) cobalamin biosynthesis pathway, generates hydrogenobyrinate a,c-diamide, the substrate required by EC, cobaltochelatase, which adds cobalt to the macrocycle. The equivalent reaction in the anaerobic cobalamin biosynthesis pathway is catalysed by EC, cobyrinate a,c-diamide synthase.
1.  Debussche, L., Thibaut, D., Cameron, B., Crouzet, J. and Blanche, F. Purification and characterization of cobyrinic acid a,c-diamide synthase from Pseudomonas denitrificans. J. Bacteriol. 172 (1990) 6239–6244. [PMID: 2172209]
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]