Optimization of the purification of mitochondrial F1-adenosine triphosphatase

A simple technique of purification of the soluble pig heart mitochondrial F₁-ATPase is described. It consists of removal of extrinsic proteins from mitochondrial membranes before extraction with chloroform and ammonium sulfate fractionation. A high degree of purity, an excellent stability and a good yield are attained after gel filtration through an Ultrogel ACA 34 column equilibrated in the presence of 50% glycerol. The tested properties of the F₁-ATPase prepared by this method are similar to those of the same enzyme extracted by sonication. The enzyme is virtually devoid of tightly bound nucleotides. In addition, some characteristics of the behaviour of the β subunit are shown.