Glycine dehydrogenase (decarboxylating)

Glycine decarboxylase also known as glycine cleavage system P protein or glycine dehydrogenase is an enzyme that in humans is encoded by the "GLDC" gene.
Reaction.
Glycine decarboxylase () is an enzyme that catalyzes the following chemical reaction:
Thus, the two substrates of this enzyme are glycine and H-protein-lipoyllysine, whereas its two products are H-protein-S-aminomethyldihydrolipoyllysine and CO2.
This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH2 group of donors with a disulfide as acceptor. This enzyme participates in glycine, serine and threonine metabolism. It employs one cofactor, pyridoxal phosphate.
Function.
Glycine decarboxylase is the P-protein of the glycine cleavage system in eukaryotes. The glycine cleavage system catalyzes the degradation of glycine. The P protein binds the alpha-amino group of glycine through its pyridoxal phosphate cofactor. Carbon dioxide is released and the remaining methylamine moiety is then transferred to the lipoamide cofactor of the H protein.
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).
Clinical significance.
Glycine encephalopathy is due to defects in "GLDC" or "AMT" of the glycine cleavage system.