Interaction between ubiquinone and ATPase in mitochondrial membranes.
The extraction of ubiquinone from mitochondrial membranes produces alterations of ATPase activity including a reversible loss of oligomycin sensitivity which is restored by long-chain Q-homologs, Short-chain ubiquinones like Q3 produce a loss of oligomycin and dicyclohexyl carbodiimide (DCCD) sensitivity in submitochondrial particles. The effect shows uncompetitive or noncompetitive Kinetics with respect to oligomycin or DCCD respectively. Long-chain ubiquinones have a competitive effect with Q3, thus restoring oligomycin sensitivity; they behave, however, in about the same way as Q3 in lowering the DCCD sensitivity in submitochondrial particles. On the basis of these observations we suggest that ubiquinone may be a physiological modulator of ATPase activity in the mitochondrial membrane.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D004237:Diuron / Q000494:pharmacology; D007425:Intracellular Membranes / Q000201:enzymology*; D007700:Kinetics; D008929:Mitochondria, Heart / Q000201:enzymology*; D009840:Oligomycins / Q000494:pharmacology; D014451:Ubiquinone / Q000378:metabolism*
D009840:Oligomycins; D014451:Ubiquinone; D004237:Diuron; D000251:Adenosine Triphosphatases