title: Evidence that coupling factor B is bound to the matrix side of the inner mitochondrial membrane.
abstract: Rotenone-sensitive NADH dehydrogenase activity and Lubrol stimulation of cytochrome oxidase activity were measured to assess the opposite membrane polarity of beef heart mitoplast and inside-out particle preparations. The ATP-Pi exchange activity of mitoplasts was not affected by their incubation at pH 8.9 in the presence of 5 mM EDTA (a treatment known to extract coupling factor B (F beta) from submitochondrial particles), nor was it stimulated by the addition of F beta to intact and alkaline treated mitoplast preparations. In contrast, the exchange activity of inside-out particles was decreased 18 fold by the alkaline/EDTA treatment and was almost completely restored by the addition of F beta to F beta-depleted particles. From these results it is concluded that in beef heart mitochondria, the coupling factor F beta is bound to the matrix-side of the inner mitochondrial membrane.
authors.affiliation: Department of Cell Physiology, Boston Biomedical Research Institute, Mass. 02114.
authors.forename: G
authors.initials: G
authors.lastname: Stephenson
authors.forename: D R
authors.initials: DR
authors.lastname: Sanadi
mesh_terms: D000251:Adenosine Triphosphatases / Q000378:metabolism*; D000818:Animals; D002417:Cattle; D002499:Centrifugation, Density Gradient; D003576:Electron Transport Complex IV / Q000378:metabolism; D007425:Intracellular Membranes / Q000201:enzymology*; D008929:Mitochondria, Heart / Q000378:metabolism* / Q000648:ultrastructure; D025261:Mitochondrial Proton-Translocating ATPases; D010086:Oxidative Phosphorylation Coupling Factors; D011092:Polyethylene Glycols / Q000494:pharmacology
chemical_list: D010086:Oxidative Phosphorylation Coupling Factors; D011092:Polyethylene Glycols; C005092:lubrol; D003576:Electron Transport Complex IV; D000251:Adenosine Triphosphatases; C032410:coupling factor B; D025261:Mitochondrial Proton-Translocating ATPases