Uncoupler-reversible inhibition of mitochondrial ATPase by metal chelates of bathophenanthroline. II. Comparison with other inhibitors.
(1) Trisbathophenanthroline-Fe2+ (BPh3Fe2+)alters the hyperbolic relationship between concentration of ATP and reaction velocity of F1-ATPase to sigmoidal, with a simultaneous decrease in maximal velocity. (2) BPh3Fe2+ binds to the beta-subunit of F1 and competes with the binding of aurovertin. The reversal of this effect uncouplers in enhanced by ADP and diminished by ATP. BPh3Fe2+ also changes the hyperbolic concentration dependence of aurovertin binding to sigmoidal. (3) BPh3Fe2+ stabilizes F1 against the cold inactivation and cold dissociation in an uncoupler-reversible manner. (4) BPh3Fe2+ efficiently protects F1 against the light-induced inactivation occurring in the presence of Rose Bengal, and the effect is reversed by uncouplers. (5) The results are discussed in relation to the reaction mechanism of F1-ATPase and other enzymes catalyzing the reversible hydrolysis of pyrophosphate bonds.
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D001313:Aurovertins / Q000494:pharmacology; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone / Q000494:pharmacology; D002417:Cattle; D007501:Iron / Q000494:pharmacology; D007700:Kinetics; D008929:Mitochondria, Heart / Q000201:enzymology*; D010086:Oxidative Phosphorylation Coupling Factors / Q000378:metabolism*; D010618:Phenanthrolines / Q000494:pharmacology*; D006180:Proton-Translocating ATPases; D012395:Rose Bengal / Q000494:pharmacology; D014475:Uncoupling Agents / Q000494:pharmacology*
D001313:Aurovertins; D010086:Oxidative Phosphorylation Coupling Factors; D010618:Phenanthrolines; D014475:Uncoupling Agents; D012395:Rose Bengal; D002259:Carbonyl Cyanide p-Trifluoromethoxyphenylhydrazone; C006686:bathophenanthroline; D007501:Iron; D000251:Adenosine Triphosphatases; D006180:Proton-Translocating ATPases