[Acid and alkaline denaturation of superoxide dismutase]

Optical and ESR spectra of erythrocyte superoxide dismutase denaturated with acid and alkali are described. Sharp changes in activity and spectra were found. "Residual" activity of alkaline denaturated protein was higher than of acidic denaturated sample. It is suggested that covalent bonding copper-nitrogen is essential for superoxide dismutase activity of the protein or synthetic copper complexes.