Direct identification of the fluoroaluminate and fluoroberyllate species responsible for inhibition of the mitochondrial F₁‐ATPase

In the presence of ADP, fluoroaluminate and fluoroberyllate inhibit irreversibly the soluble mitochondrial F 1 ‐ATPase. We report here direct evidence that this inhibition is related to the tight binding of [ 3 H]ADP, beryllium and fluoride to the enzyme. In the case of beryllium‐induced inhibition, the stoichiometry of bound species is 1 mol [ 3 H]ADP, 1 mol beryllium and 2 or 3 mol fluoride depending on the initial fluoride concentration used, which indicates that both the combinations ADP 1 ,Be 1 ,F 3 and ADP 1 ,Be 1 ,F 3 are competent for inhibition. In the case of aluminium‐induced inhibition, the binding stoichiometry of 4 mol fluoride per mol [ 3 H]ADP favours the following combination of bound species ADP 1 ,Al 1 ,F 4 . These results favour a model where fluorometals mimic phosphate and form an abortive complex with ADP in the catalytic site(s) of F 1 .