| Abstract: | Immunoprecipitation of uniformly labeled yeast submitochondrial preparations using a subunit-specific or a holoenzyme antiserum has been employed to determine the subunit stoichiometry of the oligomycin-sensitive ATPase complex. The Triton-solubilized enzyme consists of 10 types of subunits. The number of copies of each subunit, in order of decreasing molecular weight, is 3:3:1:2:1:2:2:1:2:3. on the basis of the stoichiometry data, the ATPase complex has a molecular weight of 5.8 x 10(5) and contains a minimum of 20 polypeptide chains. Analysis of water-soluble ATPase (F1-ATPase) indicates that the stoichiometry of the three largest subunits of the enzyme is preserved in the absence of the other subunits. The molecular weights of both forms of the ATPase, derived from stoichiometry data, agree well with measurements obtained from gel filtration and sedimentation studies. The implications of these data for the structure, function, and assembly of the complex are discussed. |
