A method of isorhodopsin analysis and the photoreversal of rhodopsin intermediates.

ABSTRACT Following exposure to a brief flash of light, the visual pigment rhodopsin passes through a succession of thermally labile intermediate stages. These photoproducts, some of which seem intimately associated with visual excitation, are traditionally studied by observing their absorbance spectrum changes within several milliseconds of the flash. We have developed a new technique of photoreversal and analysis. This procedure interrupts the succession of intermediates and permits accurate measurement of the substances in the resulting mixture. Such experiments may permit us to examine, independent of spectral changes, molecular changes related to visual excitation and pigment regeneration.