The enzyme system for cleavage of glycine (glycine cleavage system; GCS; EC 2.1.2.10), which is confined to the mitochondria, is composed of 4 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). Glycine encephalopathy (GCE; MIM 605899) may be due to a defect in any one of these enzymes; see MIM 238310, MIM 238330, and MIM 238331.[supplied by OMIM]