Cobalamin metabolic pathway

The cobalamin metabolic pathway encompasses the absorption, transport, intracellular processing, and utilization of vitamin B12 (cobalamin). This pathway involves dietary release of cobalamin, gastric and intestinal carrier proteins (haptocorrin, intrinsic factor), enterocyte transporters (e.g., cubilin), cellular uptake via receptors such as CD320, and complex intracellular conversion by enzymes including MMACHC and MMADHC. The ultimate metabolic products, methylcobalamin and adenosylcobalamin, serve as essential cofactors for methionine synthase, supporting methyl group transfer and nucleotide synthesis, and methylmalonyl-CoA mutase, supporting fatty acid metabolism and mitochondrial function[1][5][3][7]. Disruptions at various points cause a spectrum of inherited and acquired diseases, many of which are currently managed by targeted vitamin supplementation or adjunct therapies, though the pathway as a whole is *not* classically considered a single therapeutic target.

Other names

Vitamin B12 metabolic pathwayCobalamin metabolismVitamin B12 pathway

Supplementation to bypass metabolic blocks or correct deficiency (hydroxocobalamin, methylcobalamin, cyanocobalamin) Cofactor replacement for cobalamin-dependent enzymes such as methionine synthase and methylmalonyl-CoA mutase Remethylation pathway support (betaine as methyl donor)