Reversible inhibition of electron transfer in the ubiquinol

Abstract
Electron transfer through the ubiquinol:cytochrome c 1-segment of liver mitochondria isolated from hibernating ground squirrels Citellus undulatus is repressed by 70–80% as compared to mitochondria from the active animals. The inhibition site is likely to be localized between ubiquinone and the cytochrome bc 1, complex. Partial release of the inhibition can be observed upon swelling of the isolated mitochondria in a hypoosmotie medium, the effect being prevented by phospholipase A2 inhibitors. Possible role of phospholipase A2 in regulation of ubiquinol oxidation by complex bc 1, is discussed.