[Photochemical transformations of bacteriorhodopsin]

Results of experimental studies of bacteriorhodopsin photochemical transformations of purple membranes at low temperatures are presented. A scheme of reactions of light-adapted bacteriorhodopsin is proposed, some regularities of its phototransformations are considered. Relationships between quantum yields of direct and reverse photoreactions and absorption spectra of the states initiated during phototransformations of the pigment are determined. Proceeding from spectroscopic data the mechanisms of photochemical processes in bacteriorhodopsin are discussed. The author's and literature data point to the participation of retinal structural changes, of alterations in retinal interactions with opsin and of proton in bacteriorhodopsin photoreactions.