Adenosylcobalamin
Adenosylcobalamin, also known as coenzyme B12, cobamamide, and dibencozide, is, along with methylcobalamin, one of the biologically active forms of vitamin B12.
Adenosylcobalamin participates as a cofactor in radical-mediated 1,2-carbon skeleton rearrangements. These processes require the formation of the deoxyadenosyl radical through homolytic dissociation of the carbon-cobalt bond. This bond is exceptionally weak, with a bond dissociation energy of 31 kcal/mol, which is further lowered in the chemical environment of an enzyme active site. An enzyme that uses adenosylcobalamin as a cofactor is methylmalonyl-CoA mutase.
