Glycine Dehydrogenase (GLDC)

Degradation of glycine is brought about by the glycine cleavage system, which is composed of four mitochondrial protein components: P protein (a pyridoxal phosphate-dependent glycine decarboxylase), H protein (a lipoic acid-containing protein), T protein (a tetrahydrofolate-requiring enzyme), and L protein (a lipoamide dehydrogenase).

GLDC is the P protein, which binds to glycine and enables the methylamine group from glycine to be transferred to the T protein. Defects in this gene are a cause of nonketotic hyperglycinemia (NKH). The GLDC gene spans at least 135 kb and contains 25 exons. All donor and acceptor sites adhered to the canonical GT-AG rule, except for the donor site of intron 21, where a variant form GC is used instead of GT.