MMACHC

Methylmalonic aciduria and homocystinuria type C protein (MMACHC) 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. This function has also been attributed to cobalamin reductases. The MMACHC gene product and cobalamin reductases enable the interconversion of cyano- and alkylcobalamins.

Clinical significance
Mutations are associated with combined homocystinuria and methylmalonic acidemia.