Oxidative reactivity of Cu–TESHHK– and its alanine analogues

Abstract

Redox properties of Cu(II) complexes of the terminally blocked hexapeptide –TESHHK– and a series of its alanine substituted analogs: –TASHHK–, –TEAHHK–, –TESAHK–, –TESHAK–, were investigated in their reactions with hydrogen peroxide in solution and by cyclic voltammetry in a broad range of pH. The formation of reactive oxygen species was followed with the use of spectrophotometric indicators, NDMA and NBT. The results indicate that the ability of these complexes to generate hydroxyl-like radicals correlates with the formation of active Cu(III) complexes resulting from the oxidation of Cu(II) by H₂O₂, which interact with further H₂O₂ molecules specifically.