The glycine cleavage system catalyzes the degradation of glycine. The P protein binds the alpha-amino group of glycine through its pyridoxal phosphate cofactor; CO(2) is released and the remaining methylamine moiety is then transferred to the lipoamide cofactor of the H protein. (R)-N(6)-lipoyl-L-lysyl-[glycine-cleavage complex H protein] + glycine + H(+) = (R)-N(6)-(S(8)-aminomethyldihydrolipoyl)-L-lysyl-[glycine-cleavage complex H protein] + CO2 The glycine cleavage system is composed of four proteins: P, T, L and H. By glycine. Belongs to the GcvP family.