Stabilization of rat liver mitochondrial F1-adenosine triphosphatase during chloroform-induced solubilization

Inhibition of mitochondrial ATPase by dicarbopolyborate, a new enzyme inhibitor

Polyborate anions were found to inhibit mitochondrial ATPase. Mercapto and chloro derivatives of dicarbononaborates showed full inhibition of the enzyme activity at 0.5-0.8 mM. The inhibitory effect of dodecaborates was lower. The inhibition was of competitive type with respect to ATP. The inhibition of soluble F1-ATPase indicates a direct interaction of the polyborate anion with the catalytic part of the enzyme molecule.

Proton ATPase of rat liver mitochondria: a rapid procedure for purification of a stable, reconstitutively active F1 preparation using a modified chloroform method

A method is described for the purification of rat liver F1-ATPase by a modification of the chloroform extraction procedure originally described by Beechey et al. (Biochem. J. (1975) 148, 533). Purified liver membrane vesicles are extracted with chloroform in the presence of ATP and EDTA. The procedure yields pure F1 in only 2-3 h without the necessity of ion-exchange chromatography. The enzyme exhibits the alpha, beta, gamma, delta, and epsilon bands characteristic of F1-ATPase. It has a high ATPase specific activity, and is reconstitutively active, catalyzing high rates of ATP synthesis. Significantly, it can be readily crystallized. If desired, the enzyme can be passed over a gel filtration column to place it in a stabilizing phosphate-EDTA buffer, lyophilized and stored indefinitely at -20 degrees C.