COPPER(II) COMPLEXES OF LOW-MOLECULAR-WEIGHT DERIVATIVES OF THYMOPOIETIN

Copper(II) complexes of tri- and tetrapeptides containing either carbo xylate or amide group in the side chain were studied by potentiometric and spectroscopic methods. The ligands are tri- and tetrapeptide segm ents of the hormones thymopoietin and splenin. It was found that inter nal aspartyl residues significantly enhance the metal binding ability of oligopeptides, resulting in the cooperative deprotonation of the am ide nitrogens preceding the aspartyl residue, while the subsequent ami de groups do not take part in metal ion coordination. Glutamyl residue s have no significant effect on the complex formation processes of oli gopeptides.