Dimethylglycine Dehydrogenase (DMGDH)

DMGDH encodes an enzyme involved in the catabolism of choline, catalyzing the oxidative demethylation of dimethylglycine to form sarcosine. Mutation in this gene causes dimethylglycine dehydrogenase deficiency, characterized by a fishlike body odor, chronic muscle fatigue, and elevated levels of the muscle form of creatine kinase in serum.

Subsequently, sarcosine dehydrogenase (SDH) converts sarcosine to glycine via a similar reaction. Both enzymes are found as monomers in the mitochondrial matrix, and both contain 1 mol of covalently bound flavin adenine dinucleotide. DMGDH and SDH also utilize a noncovalently bound folate coenzyme that receives the 1-carbon groups that are removed by DMGDH and SDH, forming active formaldehyde.