Respiration-dependent K+ fluxes across the limiting membranes of isolated rat liver mitochondria, measured by means of 42K, are stimulated by the oxidative phosphorylation inhibitor dibutylchloromethyltin chloride (DBCT). A lack of effect of Cl- concentration indicates that the stimulation of K+ flux by DBCT is not attributable to Cl-/OH- exchange activity. The mercurial mersalyl was previously shown to stimulate respiration-dependent K+ influx. The combined presence of mersalyl plus DBCT results in a greater stimulation of K4 influx than is caused by either DBCT or mersalyl alone. The oxidative phosphorylation inhibitor oligomycin, which alone has no effect on respiration-dependent K+ influx, enhances the stimulatory effect of mersalyl on K+ influx. The data are consistent with, although not proof of, a direct interaction of the K+ transport mechanism with the mitochondrial energy transduction apparatus.
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http://dx.doi.org/10.1007/BF00744076 | DOI Listing |
The properties of the components of the mitochondrial ATPase which interact with modulators of energy transduction have been examined. The chromatographic behavior and the size of the components which bind trialkyl tins, carbodiimides and uncouplers, have been shown to be different. However, they all appear to be proteolipids with apparent molecular weights around 10,000.
View Article and Find Full Text PDFPreincubation of coupled submitochondrial particles with low concentrations of triorganotin compounds results in complete inhibition of the oligomycin-sensitive ATPase activity without any significant effect on the rate of succinate-driven ATP synthesis. The residual ATP synthetic activity is inhibited by oligomycin and uncouplers. The differential inhibition of ATP synthesis and hydrolysis by the triorganotin compounds examined suggests that the two processes are not 'mirror images' of each other, but that they occur through different routes and that the F1F0-ATPase is at least bifunctional.
View Article and Find Full Text PDFJ Bioenerg Biomembr
October 1983
Biology Department, Rensselaer Polytechnic Institute, Troy, New York 12181, USA.
The oxidative phosphorylation inhibitor DBCT (dibutylchloromethyltin chloride) inhibits state 3 respiration at a concentration less than that which stimulates K+ flux into respiring rat liver mitochondria. Inhibition of ADP-stimulated respiration by DBCT can be reversed or blocked by the dithiol 2,3-dimercaptopropanol. The data are consistent with previous suggestions that DBCT may interact with the ATP synthase via reaction with a dithiol group.
View Article and Find Full Text PDFJ Bioenerg Biomembr
February 1982
Respiration-dependent K+ fluxes across the limiting membranes of isolated rat liver mitochondria, measured by means of 42K, are stimulated by the oxidative phosphorylation inhibitor dibutylchloromethyltin chloride (DBCT). A lack of effect of Cl- concentration indicates that the stimulation of K+ flux by DBCT is not attributable to Cl-/OH- exchange activity. The mercurial mersalyl was previously shown to stimulate respiration-dependent K+ influx.
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