49] Low-temperature spectrophotometry of intermediates of rhodopsin

Abstract

Publisher Summary This chapter discusses the low-temperature spectrophotometry of intermediates of rhodopsin. It is well known that the absorption spectrum of rhodopsin in the visible range is in good agreement with the scotopic luminosity curve. As it takes a few milliseconds to generate the receptor potential of the visual cell after capture of a photon, the photoreaction of rhodopsin in less than a few milliseconds is important for elucidating the function of rhodopsin in visual transduction. Because such a fast photoreaction was so difficult to study at room temperature, most investigations had been carried out at low temperatures, where the thermal reaction rate of intermediates of rhodopsin is remarkably reduced. The application of low-temperature spectrophotometry to the rhodopsin system has led to discovery of several intermediates in the process of photobleaching of rhodopsin.