Reaction: S-adenosyl-L-methionine + precorrin-5 + H2O = S-adenosyl-L-homocysteine + precorrin-6A + acetate
For diagram click here and mechanism here.
Other name(s): precorrin-6X synthase (deacetylating); CobF
Systematic name: S-adenosyl-L-methionine:precorrin-5 C1-methyltransferase (deacetylating)
Comments: In the aerobic cobalamin biosythesis pathway, four enzymes are involved in the conversion of precorrin-3A to precorrin-6A. The first of the four steps is carried out by EC 126.96.36.199, precorrin-3B synthase (CobG), yielding precorrin-3B as the product. This is followed by three methylation reactions, which introduce a methyl group at C-17 (CobJ; EC 188.8.131.52), C-11 (CobM; EC 184.108.40.206) and C-1 (CobF; EC 220.127.116.11) of the macrocycle, giving rise to precorrin-4, precorrin-5 and precorrin-6A, respectively.
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, PDB, CAS registry number:
1. Debussche, L., Thibaut, D., Cameron, B., Crouzet, J. and Blanche, F. Biosynthesis of the corrin macrocycle of coenzyme B12 in Pseudomonas denitrificans. J. Bacteriol. 175 (1993) 7430-7440. [PMID: 8226690]
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]