Translations:Hydroxocobalamin/17/en

Mechanism of action

Vitamin B₁₂ refers to a group of compounds called cobalamins that are available in the human body in a variety of mostly interconvertible forms. Together with folate, cobalamins are essential cofactors required for DNA synthesis in cells where chromosomal replication and division are occurring—most notably the bone marrow and myeloid cells. As a cofactor, cobalamins are essential for two cellular reactions:

• the mitochondrial methylmalonyl-CoA mutase conversion of methylmalonic acid (MMA) to succinate, which links lipid and carbohydrate metabolism, and
• the activation of methionine synthase, which is the rate-limiting step in the synthesis of methionine from homocysteine and 5-methyltetrahydrofolate.