MMACHC

Methylmalonic aciduria and homocystinuria type C protein is a protein that in humans is encoded by the MMACHC gene.

Function

The C-terminal region of the product of the MMACHC gene is similar to TonB, a bacterial protein involved in energy transduction for cobalamin uptake. The MMACHC gene product catalyzes the decyanation of cyanocobalamin as well as the dealkylation
of alkylcobalamins including methylcobalamin and adenosylcobalamin. The MMACHC gene product is characterised as a cyanocobalamin reductase (cyanide-eliminating) and a alkylcobalamin reductase. It enables the interconversion of cyano- and alkylcobalamins.

Clinical significance

Mutations are associated with combined homocystinuria and methylmalonic acidemia.