IUBMB Enzyme Nomenclature


Accepted name: cobalt-precorrin-6B (C15)-methyltransferase [decarboxylating]

Reaction: S-adenosyl-L-methionine + cobalt-precorrin-6B = S-adenosyl-L-homocysteine + cobalt-precorrin-7 + CO2

For diagram of reaction, click here

Other name(s): cbiT (gene name); S-adenosyl-L-methionine:precorrin-7 C15-methyltransferase (C12-decarboxylating); cobalt-precorrin-7 (C15)-methyltransferase [decarboxylating]

Systematic name: S-adenosyl-L-methionine:precorrin-6B C15-methyltransferase (C12-decarboxylating)

Comments: This enzyme, which participates in the anaerobic (early cobalt insertion) adenosylcobalamin biosynthesis pathway, catalyses both methylation at C-15 and decarboxylation of the C-12 acetate side chain of cobalt-precorrin-6B. The equivalent activity in the aerobic adenosylcobalamin biosynthesis pathway is catalysed by the bifunctional enzyme EC, precorrin-6B C5,15-methyltransferase (decarboxylating).

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:


1. Keller, J.P., Smith, P.M., Benach, J., Christendat, D., deTitta, G.T. and Hunt, J.F. The crystal structure of MT0146/CbiT suggests that the putative precorrin-8w decarboxylase is a methyltransferase. Structure 10 (2002) 1475-1487. [PMID: 12429089]

2. Santander, P.J., Kajiwara, Y., Williams, H.J. and Scott, A.I. Structural characterization of novel cobalt corrinoids synthesized by enzymes of the vitamin B12 anaerobic pathway. Bioorg. Med. Chem. 14 (2006) 724-731. [PMID: 16198574]

3. Moore, S.J., Lawrence, A.D., Biedendieck, R., Deery, E., Frank, S., Howard, M.J., Rigby, S.E. and Warren, M.J. Elucidation of the anaerobic pathway for the corrin component of cobalamin (vitamin B12). Proc. Natl. Acad. Sci. USA 110 (2013) 14906-14911. [PMID: 23922391]

[EC created 2010, modified 2013]

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