ACTIVATION OF HYDROGEN-PEROXIDE BY COPPER(II) COMPLEXES WITH SOME HISTIDINE-CONTAINING PEPTIDES AND THEIR SOD-LIKE ACTIVITIES

The reactivities of copper(II) complexes with histidine-containing oli gopeptides towards active oxygen species such as hydrogen peroxide (H2 O2) and superoxide ion (O-2(-)) were investigated by electron spin res onance (ESR)-spin trapping and thiobarbituric acid (TBA) methods. At p hysiologicaI pH values, Cu(II) complexes with oligopeptides containing histidyl residue at the N-terminal could more easily activate H2O2 to yield hydroxyl radical (.OH) than other Cu(II)-oligopeptide complexes containing histidyl residue in the second or third position. Further, it was suggested that since all Cu(II)-oligopeptide complexes examine d could scavenge O-2(-), these complexes have SOD-like activities.