Studies in rhodopsin. 3. Rhodopsin and transient orange

Abstract

The existence of transient orange was first estab- lished by Lythgoe & Quilliam (1938), who showed that if a rhodopsin solution was irradiated at a tem- perature near 00, a comparatively stable orange colour resulted, but if the solution was warmed to room temperature it became much paler (colourless at alkaline pH). The unstable orange substance showed A... at about 470 m,. and, on warming, this 'transient orange ' changedto' indicator yellow'. Further work (Broda & Goodeve, 1941) showed that at -70transient orange was stable and insensitive to light. Lythgoe accordingly formulated the photodecomposition of rhodopsin as follows: