[The role of copper atoms in the cytochrome oxidase reaction].

It was found that cytochrome oxidase from bovine cardiac muscle possesses marked superoxide dismutase activity. Superoxide dismutase activity is inhibited by cyanide and azide or by alkaline or thermal treatments. This activity is also suppressed by chelating agents, e.g. bathocuproin. The data obtained indicate that superoxide dismutase activity of cytochrome oxidase is due to the copper atoms of the enzyme. The experiments on the copper-containing subunit support this conclusion. Possible physiological significance of superoxide dismutase activity of cytochrome oxidase is discussed.