Effect of ionic strength on membrane potential generation in reconstituted cytochrome c oxidase.
In this study we applied the potential-sensitive fluorescent dye indocyanine to measure the initial rate of membrane potential development in liposomes containing reconstituted cytochrome c oxidase from bovine heart. A linear relationship was found between the initial rate of membrane potential development, related to the H+/e(-)-stoichiometry, and the rate of electron flow at various substrate concentrations. By increasing the salt concentration a decrease of the initial rate of membrane potential development was found. A similar dependence on the salt concentration was also found for the membrane potential under steady state conditions. The data further demonstrate variation of the H+/e(-)-stoichiometry in cytochrome c oxidase depending on the salt concentration in the buffer.
Ivashchuk-Kienbaum YuA
Fachbereich Chemie der Philipps-Universität, Marburg, Germany.
Kadenbach
B
B
D000818:Animals; D002417:Cattle; D003576:Electron Transport Complex IV / Q000378:metabolism*; D005456:Fluorescent Dyes; D007700:Kinetics; D008081:Liposomes / Q000378:metabolism; D008564:Membrane Potentials; D008928:Mitochondria / Q000201:enzymology; D009994:Osmolar Concentration; D010101:Oxygen Consumption; D013050:Spectrometry, Fluorescence / Q000295:instrumentation
D005456:Fluorescent Dyes; D008081:Liposomes; D003576:Electron Transport Complex IV