The glycine cleavage system catalyzes the degradation of glycine. The P protein (GLDC) 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 (GCSH). {ECO:0000269|PubMed:1993704, ECO:0000269|PubMed:1996985, ECO:0000269|PubMed:28244183}. This is the function of GLDC (glycine decarboxylase, ENSG00000178445).