Control of proton transport across the double electrical layers of mitochondrial membranes
Dragunova, S.F.; Krasinskaia, I.P.; Iaguzhinskiĭ, L.S.
Biokhimiia 46(6): 1087-1095
1981
ISSN/ISBN: 0320-9725 PMID: 7260195 Document Number: 179741
The effects of cardiolipin, dodecylsulfate anion and K+ on inhibition of respiration of intact and briefly frozen mitochondria by electrophilic compounds, e.g., .beta.-haloidalkylamines-p-(N,N-di-2-chlorethylamino)phenylacetic (I) and .sbd.phenylbutyric (II) acids were studied. In K+-containing media the increase of the negative surface charge of the frozen mitochondrial membrane enhances the inhibition of mitochondrial respiration. In media without K+ this effect is absent. The inhibition of mitochondrial respiration by I and II is due to a local increase of activity of the acids in mitochondrial membrane in the course of hydrolysis. The double electrical layers probably hamper the transport of the acid from the hydrophobic zone of the membrane into the environment including the water phase. Using this model, it was demonstrated that when the double electrical layer is destroyed, the inhibition of respiration by I is decreased at increased buffer capacity of the incubation medium. Correspondingly, in intact mitochondria the buffer capacity of the medium does not practically affect the inhibition of respiration by I.