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INTERFACIAL CHARGE SEPARATION IN PHOTORECEPTOR MEMBRANES
Author(s) -
Cafiso David S.,
Hubbell Wayne L.
Publication year - 1980
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.1751-1097.1980.tb03789.x
Subject(s) - membrane , chemical physics , dielectric , aqueous solution , receptor potential , chemistry , biophysics , phase (matter) , ion , cytoplasm , boundary (topology) , membrane potential , rhodopsin , materials science , analytical chemistry (journal) , chromatography , biology , receptor , organic chemistry , biochemistry , optoelectronics , retinal , mathematical analysis , mathematics
— A rapid change in an interfacial electric potential of isolated bovine rod outer‐segment disc membranes occurs upon illumination. This potential change, which has been detected by the use of spin labelled hydrophobic ions, apparently occurs within a low dielectric boundary region of the membrane near the external (cytoplasmic) surface and is positive with respect to the aqueous exterior of the disk. The magnitude of the potential change is pH and temperature dependent and appears with a first‐order half‐time of approximately 5 ms at 23°C. A simple model in which one positive charge per bleached rhodopsin is translocated from the cytoplasmic aqueous space into the membrane low dielectric boundary region readily accounts for all experimental observations. The similarity of the boundary potential change to the R 2 phase of the early receptor potential suggests that the two have the same molecular origin.