The MMADHC gene provides instructions for making a protein that helps convert vitamin B12 (also called cobalamin) into one of two molecules, adenosylcobalamin (AdoCbl) or methylcobalamin (MeCbl). AdoCbl is required for the normal function of an enzyme known as methylmalonyl CoA mutase. This enzyme helps break down certain protein building blocks (amino acids), fat building blocks (fatty acids), and cholesterol. AdoCbl is called a cofactor because it helps methylmalonyl CoA mutase carry out its function. MeCbl is also a cofactor, but for an enzyme known as methionine synthase. This enzyme converts the amino acid homocysteine to another amino acid, methionine. The body uses methionine to make proteins and other important compounds.
Research indicates that the MMADHC protein plays a role in one of the last steps in AdoCbl and MeCbl formation. Together with another protein called MMACHC (produced from the MMACHC gene), MMADHC transports vitamin B12 to regions of the cell in which each cofactor is needed: specialized structures that serve as energy-producing centers (the mitochondria), where AdoCbl functions, or the fluid inside the cell (the cytoplasm), where MeCbl functions. Additional chemical reactions then convert vitamin B12 into AdoCbl or MeCbl.
Other Names
C2orf25; cblD; CL25022; methylmalonic aciduria (cobalamin deficiency) cblD type, with homocystinuria; methylmalonic aciduria and homocystinuria type D protein, mitochondrial; methylmalonic aciduria and homocystinuria type D protein, mitochondrial precursor; methylmalonic aciduria and homocystinuria, cblD type; MMAD_HUMAN
Related Genetics Topics
- Methylmalonic acidemia — MedlinePlus Genetics
- Homocystinuria — MedlinePlus Genetics
- Methylmalonic acidemia with homocystinuria — MedlinePlus Genetics
Identifiers
- NCBI Gene: 27249
- OMIM: 611935
Source: MedlinePlus Genetics, U.S. National Library of Medicine.
