Vitamin B12-dependent enzyme

Vitamin B12-dependent enzymes are a diverse family of proteins that require the organometallic cofactor cobalamin (vitamin B12) for catalytic activity. They fall into three main subfamilies based on their reaction chemistry: adenosylcobalamin-dependent isomerases, which catalyze radical-mediated rearrangements; methylcobalamin-dependent methyltransferases, which mediate transfer of methyl groups; and dehalogenases found primarily in anaerobic bacteria that catalyze reductive dehalogenation reactions. These enzymes play essential roles in amino acid metabolism, fatty acid breakdown, DNA synthesis, and detoxification pathways. Defects in individual members cause serious human diseases including megaloblastic anemia and inherited metabolic disorders such as methylmalonic acidemia and homocystinuria. While not themselves drug targets in the traditional sense outside rare cases like bacterial dehalogenases exploited biotechnologically, their function depends critically on adequate levels of dietary or supplemental vitamin B12.

Other names

Cobalamin-dependent enzymeCoenzyme B12-dependent enzymeCobalamin enzymeB12-enzyme

For drugs/supplements like vitamin B12 itself: Cofactor replacement for defective or deficient enzymatic activity. For potential inhibitors/antagonists (rare): Competitive inhibition at the cobalamin-binding site.