Idebenone-induced recovery of glycerol-3-phosphate and succinate oxidation inhibited by digitonin.

H Rauchová, M Vokurková, Z Drahota

Physiological research / Academia Scientiarum Bohemoslovaca 2012

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Digitonin solubilizes mitochondrial membrane, breaks the integrity of the respiratory chain and releases two mobile redox-active components: coenzyme Q (CoQ) and cytochrome c (cyt c). In the present study we report the inhibition of glycerol-3-phosphate- and succinate-dependent oxygen consumption rates by digitonin treatment. Our results show that the inhibition of oxygen consumption rates is recovered by the addition of exogenous synthetic analog of CoQ idebenone (hydroxydecyl-ubiquinone; IDB) and cyt c. Glycerol-3-phosphate oxidation rate is recovered to 148 % of control values, whereas succinate-dependent oxidation rate only to 68 %. We find a similar effect on the activities of glycerol-3-phosphate and succinate cytochrome c oxidoreductase. Our results also indicate that succinate-dependent oxidation is less sensitive to digitonin treatment and less activated by IDB in comparison with glycerol-3-phosphate-dependent oxidation. These findings might indicate the different mechanism of the electron transfer from two flavoprotein-dependent dehydrogenases (glycerol-3-phosphate dehydrogenase and succinate dehydrogenase) localized on the outer and inner face of the inner mitochondrial membrane, respectively.

Citation

H Rauchová, M Vokurková, Z Drahota. Idebenone-induced recovery of glycerol-3-phosphate and succinate oxidation inhibited by digitonin. Physiological research / Academia Scientiarum Bohemoslovaca. 2012;61(3):259-65