Activation of F₁ ‐ATPase isolated from potato tuber mitochondria

The ATP‐hydrolyzing activity of F 1 ‐ATPase purified from potato tubers mitochondria was stimulated 2‐ and 3.5‐fold by anions, chloride and bicarbonate, respectively, and 5.5‐ and 6.5‐fold by detergents, octyl glucoside and lauryl dimethylamine oxide (LDAO), respectively. The maximal specific activity of the activated F 1 , 129 μmol/min per mg protein is the highest activity of plant mitochondrial F 1 hitherto reported and exceeds several‐fold values reported earlier. In the absence of activators F 1 ‐catalyzed ATP hydrolysis exhibits non‐linear double‐reciprocal plots of [ATP] −1 vs v −1 indicative of negative cooperativity, while in the presence of activators, linear plots are observed. It is suggested that the activators reduce the cooperativity originating from the interaction between different subunits of the enzyme.