IUBMB Enzyme Nomenclature


Accepted name: precorrin-8X methylmutase

Reaction: precorrin-8X = hydrogenobyrinate

For diagram of reaction click here.

Other name(s): precorrin isomerase; hydrogenobyrinic acid-binding protein; cobH (gene name)

Systematic name: precorrin-8X 11,12-methylmutase

Comments: The enzyme, which participates in the aerobic (late cobalt insertion) adenosylcobalamin biosynthesis pathway, catalyses the conversion of precorrin-8X to hydrogenobyrinate by methyl rearrangement. The equivalent enzyme in the anaerobic pathway is EC, cobalt-precorrin-8 methylmutase.

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


1. Thibaut, D., Couder, M., Famechon, A., Debussche, L., Cameron, B., Crouzet, J., Blanche, F. The final step in the biosynthesis of hydrogenobyrinic acid is catalyzed by the cobH gene product with precorrin-8X as the substrate. J. Bacteriol. 174 (1992) 1043-1049. [PMID: 1732194]

2. Roth, J.R., Lawrence, J.G., Rubenfield, M., Kieffer-Higgins, S., Church, G.M. Characterization of the cobalamin (vitamin B12) biosynthetic genes of Salmonella typhimurium. J. Bacteriol. 175 (1993) 3303-3316. [PMID: 8501034]

3. Roessner, C.A., Warren, M.J., Santander, P.J., Atshaves, B.P., Ozaki, S., Stolowich, N.J., Iida, K., Scott, A.I. Expression of Salmonella typhimurium enzymes for cobinamide synthesis. Identification of the 11-methyl and 20-methyl transferases of corrin biosynthesis. FEBS Lett. 301 (1992) 73-78. [PMID: 1451790]

4. Crouzet, J., Cameron, B., Cauchois, L., Rigault, S., Rouyez, M.C., Blanche, F. , Thibaut D., Debussche, L. Genetic and sequence analysis of an 8.7-kilobase Pseudomonas denitrificans fragment carrying eight genes involved in transformation of precorrin-2 to cobyrinic acid. J. Bacteriol. 172 (1990) 5980-5990. [PMID: 2211521]

5. Shipman, L.W., Li, D., Roessner, C.A., Scott, A.I. and Sacchettini, J.C. Crystal structure of precorrin-8x methyl mutase. Structure 9 (2001) 587-596. [PMID: 11470433]

[EC created 1999 as EC, transferred 2014 to EC]

Return to EC 5.4.99 home page
Return to EC 5.4 home page
Return to EC 5 home page
Return to Enzymes home page
Return to IUBMB Biochemical Nomenclature home page