[Interaction of inorganic anions with copper atoms of cytochrome oxidase].

The effects of cyanide, thiocyanide, azide, nitrite, nitrate, ferricyanide, persulfate, sulfide and halogenides on the intensities of the EPR spectrum and the band of 825 nm of cardiac cutochrome oxidase were studied. It was shown that according to their action on the copper the anions may be classified into three groups: 1) anions inducing the reduction of the copper (CN-, CNS-, S2-) anions changing the environment of the copper (N3-, NO2-); 3) anions slightly interacting with the copper (NO3-, halogenides). The incubation of cytochrome oxidase with ferricyanide led to the formation of a free-radical component without causing any pronounced changes in the copper environment; however, treatment of the protein with persulfate was accompanied by an irreversible modification of the copper EPR spectrum.