Quaternary Structure of Bovine Cytochrome Oxidase

摘要: A hydrodynamically homogeneous preparation of bovine mitochondrial cytochrome c oxidase can be obtained by anion-exchange chromatography alkaline-treated enzyme, followed a gel permeation step, which further removes some (aggregated) apoprotein. The molecular weight, Mr the monodisperse enzyme in Triton X-100 was found to 210000. This complex is composed six different polypeptides, with summing up about 110000 toto, relative one-to-one stoichiometry. Two sets these subunits constitute 210000-Mr complex. In contrast our earlier report [Saraste, Penttila, Coggins, and Wikstrom, FEBS Lett. 114 (1980) 35–38] contains four (and not two) haems A, therefore represents dimer aa3. One proposed seven subunits, number III, lacking this preparation.