A study on a novel superoxide dismutase mimic bis(dioxotetraamine) copper(II) complex — kinetics of catalytic dismutation of superoxide anion by pulse radiolysis and solution equilibrium

Abstract A mimic of Cu 2 Zn 2 SOD has been investigated in detail. Its stability in solution has been obtained by the solution equilibrium study of N,N′,N″,N‴ -tetra(2-aminoethyl)-1,1,2,2,-ethanetetraamide with copper ions. The kinetics of catalytic dismutation of superoxide anions by copper(II) complex [Cu 2 (H −4 L)] was studied using pulse radiolysis. The rate constant of catalytic dismutation of O 2 − was determined to be K cat = 2.81 × 10 8 (pH = 7.8) and 1.63 × 10 8 mol −1 dm 3 s −1 (pH = 8.3) and the mechanism of catalytic dismutation of O 2 − was suggested. The k cat values have been compared with those of other Cu 2 Zn 2 SOD (SOD = superoxide dismutase) mimics. The experimental results show that the novel mimic exhibits high activity and stability at about pH = 7.8.