Effects of quercetin and F1 inhibitor on mitochondrial ATPase and energy-linked reactions in submitochondrial particles.

Quercetin (3,3',4',5,7-pentahydroxyflavone) shares certain properties with the mitochondrial ATPase inhibitor protein. At low concentrations it inhibits both soluble and particulate mitochondrial ATPase and has no effect on oxidative phosphorylation in submitochondrial particles. Unlike the mitochondrial inhibitor protein quercetin inhibits the ATP-dependent reduction of NAD+ by succinate in fully reconstituted submitochondrial particles. A comparison of various flavones indicates that the hydroxyl groups at the 3' and perhaps 3 position are important for the inhibition of ATPase activity.