title: The effect of Co(III)(NH3)4ATP on the kinetics of beef heart mitochondrial ATPase.
abstract: Bidentate cobalt(III)tetraamine adenosine triphosphate [Co(NH3)4ATP] was investigated as an inhibitor of the beef heart mitochondrial F1-ATPase. The compound was found to have a mixed noncompetitive mechanism with a Ki of 0.4 mM and an alpha of 1.4 during ATP hydrolysis. Co(NH3)4ATP also noncompetitively inhibited ATP hydrolysis in the presence of bicarbonate. ITP hydrolysis was similarly affected. Co(NH3)4ATP was also used in dual inhibitor studies with adenylylimidodiphosphate (AMP-PNP) and azide; it was found to be mutually exclusive with AMP-PNP and azide. The compound also protected the F1 from modification by 4-chloro-7-nitrobenzofurazan. These results are discussed in terms of the regulation of the ATP hydrolysis reaction.
authors.forename: L
authors.initials: L
authors.lastname: Steinke
authors.forename: S M
authors.initials: SM
authors.lastname: Schuster
mesh_terms: D009327:4-Chloro-7-nitrobenzofurazan / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000266:Adenylyl Imidodiphosphate / Q000494:pharmacology; D000818:Animals; D001667:Binding, Competitive; D002417:Cattle; D006868:Hydrolysis; D066298:In Vitro Techniques; D007293:Inosine Triphosphate; D007700:Kinetics; D008929:Mitochondria, Heart / Q000201:enzymology*; D006180:Proton-Translocating ATPases / Q000037:antagonists & inhibitors*; D013379:Substrate Specificity
chemical_list: D007293:Inosine Triphosphate; D000266:Adenylyl Imidodiphosphate; D000255:Adenosine Triphosphate; D006180:Proton-Translocating ATPases; D009327:4-Chloro-7-nitrobenzofurazan