منابع مشابه
Geometrical Isomers of Retinene
Five crystalline retinenes have been isolated, which have every appearance of being cis-trans isomers of one another. They are all-trans retinene; three apparently mono-cis isomers: neoretinenes a and b and isoretinene a; and isoretinene b, an apparently di-cis isomer. The absorption spectra of these substances display the relations expected of cis-trans isomers. The main absorption band is dis...
متن کاملGeometrical Isomers of Retinene by Ruth Hubbard,
We have described experiments involving the use of five crystalline isomers of retinene: the ordinary crystalline substance known previously from the work of Ball, Goodwin, and Morton (1948); neoretinenes a and b, first iso. lated in our laboratory; and isoretinenes a and b, isolated in the Organic Re. search Laboratory of Distillation Products Industries (Hubbard and Wald 1952; 1952-53). By al...
متن کاملCis-trans Isomers of Vitamin a and Retinene in the Rhodopsin System
Vitamin A and retinene, the carotenoid precursors of rhodopsin, occur in a variety of molecular shapes, cis-trans isomers of one another. For the synthesis of rhodopsin a specific cis isomer of vitamin A is needed. Ordinary crystalline vitamin A, as also the commercial synthetic product, both primarily all-trans, are ineffective. The main site of isomer specificity is the coupling of retinene w...
متن کاملRetinene Isomerase
Rhodopsin is formed by the condensation of opsin with a cis isomer of retinene, called neo-b. The bleaching of rhodopsin releases all-trans retinene which must be isomerized back to neo-b in order for rhodopsin to regenerate. Both retinene isomers are in equilibrium with the corresponding isomers of vitamin A, through the alcohol dehydrogenase system. An enzyme is found in cattle retinas and fr...
متن کاملConstant variation in structure and function of geometrical isomers of acitretin under natural light.
Acitretin, a beneficial retinoid, was shown to undergo constant structural interconversions among its geometrical isomers (all-trans-acitretin, 9-cis-acitretin, 13-cis-acitretin, 9, 13-di-cis-acitretin, etc.) by photoisomerization under natural light. The photoisomerization was zero order reaction with an apparent velocity of 4x107 M/min under illumination by white fluorescent lamps (1, 200 lx)...
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ژورنال
عنوان ژورنال: Journal of General Physiology
سال: 1953
ISSN: 1540-7748,0022-1295
DOI: 10.1085/jgp.36.3.415