[Oxidative modification of cupro-zinc superoxide dismutase by reactive oxygen species]

Exposure of cupro-zinc superoxide dismutase (SOD) to hydrogen peroxide or ascorbate-Fe(III) gives rise to the extensively oxidative modification of SOD. The results showed as (1) the enzyme was irreversibly inactivated by H2O2 and ascorbate-Fe(III); (2) both human and bovine SOD showed an increase in reactivities with their antibodies; (3) the reduction and the loss of Cu(II) as well as the loss of His44, His118 and His78 indicated by 1HNMR and ESR might be responsible for the mechanism of SOD inactivation; (4) there were great changes in the primary structure and conformation in SOD; (5) the physicochemical properties of SOD were altered; (6) antigenic determinants analysis of SOD was performed and the results showed that there are at least three antigenic determinants in SOD.