Activation of hydrogen peroxide by copper(II) complexes with some histidine-containing peptides and their SOD-like activities

Abstract

The reactivities of copper(II) complexes with histidine-containing oligopeptides towards active oxygen species such as hydrogen peroxide (H 2O 2) and superoxide ion (O 2 −) were investigated by electron spin resonance (ESR)-spin trapping and thiobarbituric acid (TBA) methods. At physiological pH values, Cu(II) complexes with oligopeptides containing histidyl residue at the N-terminal could more easily activate H 2O 2 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 examined could scavenge O 2 −, these complexes have SOD-like activities.