Studies on the Mitochondrial Adenosine Triphosphatase System

An oligomycin-sensitive adenosine triphosphatase complex has been purified from bovine heart mitochondria by ammonium sulfate fractionation in presence of bile salts. With the exception of flavin and a small amount of cytochromes b and c1 the preparation is devoid of electron transfer components. The catalytic properties of the ATPase complex as judged by sensitivity to various inhibitors, specificity toward triphosphonucleotides, and activation by metals are not changed during the course of the isolation from sub-mitochondrial particles. The oligomycin-sensitive ATPase complex has been further resolved into two fractions. One of these is a soluble ATPase enzyme which is not inhibited by oligomycin and is cold inactivated. This water-soluble enzyme has been identified with the previously isolated F1. Analysis of the protein components of the oligomycin-sensitive ATPase by electrophoresis on polyacrylamide gel indicates that the enzyme complex contains in addition to the set of proteins characteristic of F1, two proteins that are not referable to F1.