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EC 6.3.5.11 Details
show Brenda entryEC number
6.3.5.11
Accepted name
cobyrinate a,c-diamide synthase
Reaction
2 ATP + cobyrinate + 2 L-glutamine + 2 H2O = 2 ADP + 2 phosphate + cobyrinate a,c-diamide + 2 L-glutamate (overall reaction);;(1a) ATP + cobyrinate + L-glutamine + H2O = ADP + phosphate + cobyrinate c-monamide + L-glutamate;;(1b) ATP + cobyrinate c-monamide + L-glutamine + H2O = ADP + phosphate + cobyrinate a,c-diamide + L-glutamate
Other name(s)
cobyrinic acid a,c-diamide synthetase,
CbiA
Systematic name
cobyrinate:L-glutamine amido-ligase (ADP-forming)
Comment
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. The equivalent reaction in the aerobic cobalamin biosynthesis pathway is catalysed by EC 6.3.5.9, hydrogenobyrinic acid a,c-diamide synthase (glutamine-hydrolysing).
History
created 2010
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1 Oxidoreductases
1.1.1 With NAD+ or NADP+ as acceptor
1.1.3.1 created 1961, deleted 1984 1.1.3.25 created 1986, deleted 2005 1.1.3.26 created 1989, deleted 2002 1.1.3.31 created 1992, deleted 2003 1.1.3.32 created 1999, deleted 2002 1.1.3.33 created 1999, deleted 2002 1.1.3.34 created 1999, deleted 2002 1.1.3.35 created 1999, deleted 2002 1.1.3.36 created 1999, deleted 2002
