REDOX CHEMISTRY OF COMPLEXES OF NICKEL(II) WITH SOME BIOLOGICALLY IMPORTANT PEPTIDES IN THE PRESENCE OF REDUCED OXYGEN SPECIES - AN ESR STUDY

The reactions between some Ni(II) oligopeptides (Gly-His-Lys, (Gly)4, Asp-Ala-His-Lys, Gly-Gly-His, beta-Ala-His, and serum albumin) and reduced oxygen species have been characterized by spin-trapping experiments using DMPO and Me2SO. Most of the peptides possessed superoxide dismutase- and catalase-like activities leading to the formation of either oxene [NiO]2+ or, in the case of beta-Ala-His, hydroxyl radicals. Both these species may affect DNA integrity through distinct mechanisms.