This is a family of glycine cleavage H-proteins, part of the glycine cleavage multienzyme complex (GCV) found in bacteria and the mitochondria of eukaryotes. GCV catalyses the catabolism of glycine in eukaryotes. A lipoyl group is attached to a completely conserved lysine residue. The H protein shuttles the methylamine group of glycine from the P protein to the T protein.

1: X-ray structure determination at 2.6-A resolution of a lipoate- containing protein: the H-protein of the glycine decarboxylase complex from pea leaves. Pares S, Cohen-Addad C, Sieker L, Neuburger M, Douce R; Proc Natl Acad Sci U S A 1994;91:4850-4853. PMID:8197146