Copper(II)-complexation by non enzymatically glycated peptides

The purpose of our work was to examine the metal binding abilities of selected peptide bound Maillard reaction products (MRPs). The N"-hippuryl-protected MRPs N'-fructoselysine and N e -carboxymethyllysine were synthesisedand measurement of stability constants for complexes formed with the physiologically important metal ions copper(II) and zinc(II) was carried out in aqueous solution (T = 298.1 K; I = 0.1M KNO 3 ) using pH-potentiometry. The stability constants of N'-fructoselysine and N e -carboxymethyllysine with Cu(II) proved that new coordination centres are formed by the nonenzymatic glycation of proteins. With zinc(II) no complexation was observed. Physiological consequences are discussed, but further studies are necessary in order to clarify the effects of this phenomenon.