PHOTOREACTIVATION OF THE CYTOCHROME-OXIDASE COMPLEX WITH CYANIDE - THE REACTION OF HEME ALPHA(3) PHOTOREDUCTION

It is shown that the electron transfer activity of isolated cytochrome oxidase inhibited by 93-95% with cyanide in low concentrations increa ses by no less than three times under exposure of visible light. It is found that irradiation with visible light increases the rate of reduc tion of cytochrome oxidase heme groups in the presence of sodium dithi onite. Based on these results, it is suggested that modification of th e catalytic and spectral characteristic of the cytochrome oxidase-cyan ide complex is due to the photostimulation of the intramolecular elect ron transport at the interheme theme a - heme a(3)) transfer stage, i. e. is caused by photoreduction of the enzyme's heme a(3)-CN complex.