Title: Porphyropsin
CAS Registry Number: 9009-58-9
Literature References: Photoreceptor protein found in the retinal rod cells of fresh water and migrating fish, lampreys, and certain amphibians. Absorption maximum approx 520-530 nm. Composed of the chromophore, 11-cis-3-dehydroretinal, q.v., bound to scotopsin, the specific protein component of rod pigments (see Opsins). Biological activity is similar to that of rhodopsin, q.v. Isoln from retinas: G. Wald, Nature 139, 1017 (1937); idem, J. Gen. Physiol. 22, 775 (1939). Prepn from 3-dehydroretinal and opsin: idem, Annu. Rev. Biochem. 22, 497 (1953). Methods of purification, prepn and assay: R. Hubbard et al., Methods Enzymol. 18, 615-653 (1971). Exposure to light initiates the conversion of porphyropsin through a series of distinct intermediates to yield opsin and trans-3-dehydroretinal. Bleaching kinetics and photochemistry: T. Yoshizawa in Handbook of Sensory Physiology Vol. VII(2), H. J. A. Dartnall, Ed. (Springer-Verlag, New York, 1972) pp 146-179. Porphyropsin may co-exist with rhodopsin in the retinas of certain amphibians and fish: T. E. Reuter et al., J. Gen. Physiol. 58, 351 (1971). Environmental effect on visual pigment formation and interconversion: P. Witkovsky et al., ibid. 72, 821 (1978); A. T. C. Tsin, D. D. Beatty, Exp. Eye Res. 30, 143 (1980). Review: G. Wald, Science 162, 230-239 (1968). |