is a member of the class-I pyridine nucleotide-disulfide oxidoreductase family. Lipoamide dehydrogenase is a component of the glycine cleavage system as well as of the alpha-ketoacid dehydrogenase complexes. DLD exists as a homodimer. DLD is involved in the hyperactivation of spermatazoa during capacitation and in the spermatazoal acrosome reaction. Mutations in its encoding gene have been identified in patients with E3-deficient maple syrup urine disease and lipoamide dehydrogenase deficiency.