Kinetic investigations of the autoxidation of adrenalin

Generation rates of superoxide anions (O2-) by autoxidizing adrenalin at pH 9.5 were determined in solutions containing either superoxide dismutase (0.85 M-1 S-1) or hydroxylamine (0.0185 M-1 S-1) as competitive scavengers. The rate constants of O2- with adrenalin and hydroxylamine were calculated for neutral and alkaline solutions. The respective values were for adrenalin: 5.6 X 10(4) M-1 S-1, pH 7.8; 7.0 X 10(3) M-1 S-1, pH 9.5--and for hydroxylamine 5.9 X 10(4) M-1 S-1, pH 7.8; 3.4 X 10(4) M-1 S-1, pH 9.5. The effects of various competitors and O2- sources on the rate constants were compared.