Mechanism of ATP hydrolysis by beef heart mitochondrial ATPase. Rate enhancements resulting from cooperative interactions between multiple catalytic sites.
نویسندگان
چکیده
منابع مشابه
Nucleotide binding sites on beef heart mitochondrial F1-ATPase. Cooperative interactions between sites and specificity of noncatalytic sites.
We have studied the properties of beef heart mitochondrial F1 having inhibitory MgADP bound at one of the three catalytic sites and various levels of occupancy of the three noncatalytic nucleotide sites including zero, two, or three ADP/ATPs or two ADP/ATP plus one GTP. The properties examined include the rate of MgATP-dependent reactivation and the rate of increase in the fraction of F1 contai...
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The effects of various substrates and alternative substrates on the hydrolytic activity of beef heart mitochondrial ATPase was examined. It was found that ATP and ADP are competitive inhibitors of ITP hydrolysis, and that in the presence of either ATP or ADP, ITP hydrolysis showed positive cooperativity. IDP inhibited ITP hydrolysis and caused positive cooperativity. When ITP was present during...
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Submitochondrial particles from beef heart, washed with dilute solutions of KCl so as to activate the latent, membrane-bound ATPase, F1, may be used to study single site catalysis by the enzyme. [gamma-32P]ATP, incubated with a molar excess of catalytic sites, a condition which favors binding of substrate in only a single catalytic site on the enzyme, is hydrolyzed via a four-step reaction mech...
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The mitochondrial F(1)F(o)-ATPase performs the terminal step of oxidative phosphorylation. Small molecules that modulate this enzyme have been invaluable in helping decipher F(1)F(o)-ATPase structure, function, and mechanism. Aurovertin is an antibiotic that binds to the beta subunits in the F(1) domain and inhibits F(1)F(o)-ATPase-catalyzed ATP synthesis in preference to ATP hydrolysis. Despit...
متن کاملInhibition of Mitochondrial F1-ATPase Activity by an Anti-a Subunit Monoclonal Antibody Which Modifies Interactions between Catalytic
A monoclonal antibody, 7B3, specific to the a subunit of the mitochondrial ATPase-ATP synthase inhibited the rate of ATP hydrolysis by either soluble F1 or electron transport particles up to a maximum of 75%. However, 7B3 did not modify the rate of ITP hydrolysis. In addition, the apparent K , for MgATP extrapolated at high ATP concentrations had the same value in the absence as in the presence...
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ورودعنوان ژورنال:
- The Journal of biological chemistry
دوره 257 20 شماره
صفحات -
تاریخ انتشار 1982