5,6-dimethylbenzimidazole synthase explained

5,6-dimethylbenzimidazole synthase
Ec Number:	1.14.99.40

5,6-dimethylbenzimidazole synthase (BluB) is an enzyme with systematic name FMNH₂ oxidoreductase (5,6-dimethylbenzimidazole forming).^{[1] [2] [3]} This enzyme catalyses the following chemical reaction

FMNH₂ + NADH + H⁺ + O₂

\rightleftharpoons 5,6-dimethylbenzimidazole + D-erythrose 4-phosphate + NAD⁺ + other product

The C-2 of 5,6-dimethylbenzimidazole is derived from C-1' of the ribityl group of FMNH₂ and 2-H from the ribityl 1'-pro-S hydrogen. This enzyme is part of the biosynthetic pathway to cobalamin (vitamin B₁₂) in bacteria.

See also

• Cobalamin biosynthesis

Notes and References

1. Gray MJ, Escalante-Semerena JC . Single-enzyme conversion of FMNH2 to 5,6-dimethylbenzimidazole, the lower ligand of B12 . Proceedings of the National Academy of Sciences of the United States of America . 104 . 8 . 2921–6 . February 2007 . 17301238 . 1815282 . 10.1073/pnas.0609270104 . 2007PNAS..104.2921G . free .
2. Ealick SE, Begley TP . Biochemistry: molecular cannibalism . Nature . 446 . 7134 . 387–8 . March 2007 . 17377573 . 10.1038/446387a . 2007Natur.446..387E . free .
3. Taga ME, Larsen NA, Howard-Jones AR, Walsh CT, Walker GC . BluB cannibalizes flavin to form the lower ligand of vitamin B12 . Nature . 446 . 7134 . 449–53 . March 2007 . 17377583 . 2770582 . 10.1038/nature05611 . 2007Natur.446..449T .