Pathways in the hydrolysis of vertebrate rhodopsin

A direct method for measuring the amount of retinal 387 was used along with spectral techniques to measure each of the intermediates in the photolysis of rhodopsin and to unequivocally determine the pathways in solution extracts of bovine rhodopsin and excised toad and skate retinas. Metarhodopsin II 380 was the earliest intermediate which hydrolyzed to retinal 387 plus opsin. In excised toad retinas three approaches were used to show that Meta III 465 decayed directly to retinal 387 plus opsin. The only pathway consistent with the data was: (Formula: See text). In solution extracts the formation and hydrolysis of N-Retinylidene-Opsin was also observed.