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CHROMOPHORE OF A LONG‐LIVED PHOTOPRODUCT FORMED WITH METARHODOPSIN III IN THE ISOLATED FROG RETINA
Author(s) -
Azuma Masami,
Azuma Katsu
Publication year - 1984
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1984.tb04623.x
Subject(s) - chromophore , rhodopsin , digitonin , chemistry , retinal , high performance liquid chromatography , photochemistry , spectrophotometry , chromatography , biochemistry , membrane
Long‐lived photoproducts of frog rhodopsin in isolated retina and digitonin solution have been investigated by spectrophotometry and their chromophores have been analyzed by high‐pressure liquid chromatography (HPLC). By irradiation (> 560 nm) at 3°C and pH 8.6, a product analogous to metarhodopsin III (MIII) is formed, whose absorption maximum is at about 450 nm. This product decays more slowly than MIII does. The results of HPLC analysis indicate that the chromophore of this photoproduct is 7‐ cis retinal and that of MIII is all‐trans retinal. The product possessing 7‐ cis retinal is called 7‐ cis photoproduct. The amount of 7‐ cis isomer in rhodopsin solution irradiated at various temperatures between 15°C and –82°C, has been determined. The results suggest that the 7‐ cis photoproduct can be formed by the photoconversion of lumirhodopsin and metarhodopsin I.