Reversible inhibition of electron transfer in the ubiquinol: Cytochrome c reductase segment of the mitochondrial respiratory chain in hibernating ground squirrels

• Published in: FEBS letters 1990-04, Vol.263 (1), p.73-76
• Main Authors: Brustovetsky, N.N., Amerkhanov, Z.G., Popova, E.Yu, Konstantinov, A.A.
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Carbonyl Cyanide m-Chlorophenyl Hydrazone - pharmacology; Cell structures and functions; Citellus undulatus; Cytochrome Reductases - metabolism; Cytochromes - metabolism; Electron flow regulation; Electron Transport; Fundamental and applied biological sciences. Psychology; Hibernation; Kinetics; Mitochondria and cell respiration; Mitochondria, Liver - drug effects; Mitochondria, Liver - enzymology; Mitochondria, Liver - metabolism; Molecular and cellular biology; NADH Dehydrogenase - metabolism; Oxidative phosphorylation; Oxygen Consumption; Phospholipase A 2; phospholipase A2; Rotenone - pharmacology; Sciuridae - physiology; Spermophilus undulatus; Ubiquinol: cytochrome c1 reductase; Ubiquinone - analogs & derivatives; Ubiquinone - metabolism
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(90)80708-Q

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 A 2 inhibitors. Possible role of phospholipase A 2 in regulation of ubiquinol oxidation by complex bc 1, is discussed.