Metal interactions with beef heart mitochondrial ATPase.

Mechanism of ATP hydrolysis by beef heart mitochondrial ATPase. Rate enhancements resulting from cooperative interactions between multiple catalytic sites.

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...

Structural preferences for the binding of chromium nucleotides by beef heart mitochondrial ATPase.

The mono- and bidentate forms of adenosine 5'-diphosphate, chromium (III) salt (CrADP) were separated using Sephadex G-10 column chromatography. The isomeric purity of the two forms was monitored using high voltage electrophoresis and column chromatography. The same techniques were employed to assess the purity of the mono-, bi-, and tridentate forms of adenosine 5'-triphosphate, chromium (III)...

Hydrolysis of adenyl-5-yl imidodiphosphate by beef heart mitochondrial ATPase.

Beef heart mitochondrial ATPase (F1) catalyzes the hydrolysis of the ATP analog adenyl-5-yl imidodiphosphate (AMP-PNP). The reaction products are inorganic phosphate and adenyl-5-yl phosphoramidate (AMP-PN) as determined by HPLC analysis. The hydrolysis occurs in both the presence and absence of added divalent metal ions and is stimulated by potassium. The kinetic properties of the hydrolytic r...

Effect of Inosine 5’-(p,y-Imido)triphosphate and Other Nucleotides on Beef Heart Mitochondrial ATPase*

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...