November 1, 1969Journal of Biological Chemistry12,878 citationsOpen Access
Superoxide Dismutase
View Full Paper
Key Points
- To purify superoxide dismutase and elucidate its role in mitigating oxidative damage.
- Superoxide dismutase was purified from bovine erythrocytes using a simple procedure.
- Electrolytic reduction of O2 in dimethylformamide generated stable superoxide radicals.
- Tissue distribution of superoxide dismutase was assessed in various mammalian tissues.
- Superoxide dismutase showed significant inhibition of reactions involving superoxide radicals.
- Copper removal was reversible, and its presence was essential for enzyme activity.
- Superoxide dismutase was found extensively distributed within mammalian organisms.
Abstract
An enzyme which catalyzes the dismutation of superoxide radicals (O2·- + O2·- + 2H+ → O2 + H2O2) has been purified by a simple procedure from bovine erythrocytes. This enzyme, called superoxide dismutase, contains 2 eq of copper per mole of enzyme. The copper may be reversibly removed, and it is required for activity. Superoxide dismutase has been shown to be identical with the previously described copper-containing erythrocuprein (human) and hemocuprein (bovine). Stable solutions of the superoxide radical were generated by the electrolytic reduction of O2 in an aprotic solvent, dimethylformamide. Slow infusion of such solutions into buffered aqueous media permitted the demonstration that O2·- can reduce ferricytochrome c and tetranitromethane, and that superoxide dismutase, by competing for the superoxide radicals, can markedly inhibit these reactions. Superoxide dismutase was used to show that the oxidation of epinephrine to adrenochrome by milk xanthine oxidase is mediated by the superoxide radical. An assay of several tissues indicates that superoxide dismutase is widely distributed within mammalian organisms.
Cite This Study
McCord et al. (1969) studied this question.