Comparison of permeant ion uptake and carotenoid band shift as methods for determining the membrane potential in chromatophores from Rhodopseudomonas sphaeroides Ga
- 15 April 1979
- journal article
- research article
- Published by Portland Press Ltd. in Biochemical Journal
- Vol. 180 (1) , 75-85
- https://doi.org/10.1042/bj1800075
Abstract
A comparison was made of 2 methods for estimating the membrane potential in chromatophores from R. sphaeroides. Illuminated chromatophores generated a potential that is apparently much larger when estimated on the basis of the red-band shift of carotenoids rather than from the extent of uptake of the permeant SCN- ion. When the chromatophores were oxidizing NADH or succinate the uptake of SCN- indicated a larger membrane potential than was estimated from the carotenoid band shift. The extent of SCN- uptake and the carotenoid-band shift respond differently to changes in the ionic composition of the reaction medium. The effects of antimycin on the carotenoid band shift and SCN- uptake are reported. The carotenoid band shift and the uptake of SCN- are responding to different aspects of the energized state.This publication has 33 references indexed in Scilit:
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