IUBMB Enzyme Nomenclature


Accepted name: precorrin-6B C5,15-methyltransferase (decarboxylating)

Reaction: 2 S-adenosyl-L-methionine + precorrin-6B = 2 S-adenosyl-L-homocysteine + precorrin-8X + CO2 (overall reaction)
(1a) S-adenosyl-L-methionine + precorrin-6B = S-adenosyl-L-homocysteine + precorrin-7 + CO2
(1b) S-adenosyl-L-methionine + precorrin-7 = S-adenosyl-L-homocysteine + precorrin-8X

For diagram of reaction click here and mechanism (click here).

Glossary: precorrin-6B = precorrin-6Y

Other name(s): precorrin-6 methyltransferase; precorrin-6Y methylase; precorrin-6Y C5,15-methyltransferase (decarboxylating); cobL (gene name)

Systematic name: S-adenosyl-L-methionine:1-precorrin-6B C5,15-methyltransferase (C-12-decarboxylating)

Comments: The enzyme, which participates in the aerobic adenosylcobalamin biosynthesis pathway, has S-adenosyl-L-methionine-dependent methyltransferase and decarboxylase activities. The enzyme is a fusion protein with two active sites; one catalyses the methylation at C15 and the decarboxylation, while the other catalyses the methylation at C5.

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number: 162995-22-4


1. Blanche, F., Famechon, A., Thibaut, D., Debussche, L., Cameron, B., Crouzet, J. Biosynthesis of vitamin B12 in Pseudomonas denitrificans: the biosynthetic sequence from precorrin-6Y to precorrin-8X is catalyzed by the cobL gene product. J. Bacteriol. 174 (1992) 1050-1052. [PMID: 1732195]

2. Deery, E., Schroeder, S., Lawrence, A.D., Taylor, S.L., Seyedarabi, A., Waterman, J., Wilson, K.S., Brown, D., Geeves, M.A., Howard, M.J., Pickersgill, R.W. and Warren, M.J. An enzyme-trap approach allows isolation of intermediates in cobalamin biosynthesis. Nat. Chem. Biol. 8 (2012) 933-940. [PMID: 23042036]

[EC created 1999, modified 2013]

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