Decarboxylation Reaction of Oxalacetic Acid by Metal Chelates. III. Metal-Peptide

Abstract

Effect of the metal-peptide systems on decarboxylation of oxa1acetic acid was examined, using copper(II), manganese(II), and nickel(II) as metals, and as peptide ligands, glycyl-glycine glycyl-alanine, glycyl-leucine, glycyl-threonine, glycyl-tyrosine, alanyl-glycine, leucyl-glycine, alanyl-alanine, histidyl-histidine, glycyl-glycyl-glycine, and glycyl-g1ycyl-g1ycy1-glycine. Among the metal-dipeptide systems, the fastest decarboxylation was observed when copper or manganese to His-His ratio was 1 : 1. None of the nickel-dipeptide systems decarboxylated oxalacetic acid faster than nickel(II) ion did. Decarboxylation studies were carried out at the rate of metal to ligand of 1 : 1, using copper(II), nickel(II), and manganese(II) as metals, and amino acid, di-, tri-, and tetra-peptide as ligands. The reaction rate for copper ligand decreased in the order of Gly>Gly-Gly>Gly-Gly-Gly=Gly-Gly-Gly-Gly for nickel-ligand in the order of Gly>Gly-Gly=Gly-Gly-Gly=Gly-Gly-Gly-Gly, and for manganese-ligand, in the order of Gly<Gly-Gly<Gly-Gly-Gly=Gly-Gly-Gly-Gly.