title: Cytochrome oxidase rotates in the inner membrane of intact mitochondria and submitochondrial particles.
abstract: A transient dichroism is detected after photolysis by a linearly polarized laser flash of the cytochrome oxidaseCO complex in bovine heart mitochondria, rat heart mitochondria, and bovine heart submitochondrial particles. A decay in the absorption anisotropy is characterized by a time constant of about 300 to 400 mus in both mitochondria and submitochondrial particles. Since vesicle tumbling in the time range less than 5 ms can be excluded in these experiments, we conclude that cytochrome oxidase rotates in the mitochondrial membrane with a relaxation time of several hundred microseconds. However, it is likely that only about one-half of cytochrome oxidase contributes to the observed decay, the remainder being relatively immobile.
mesh_terms: D000818:Animals; D002417:Cattle; D003576:Electron Transport Complex IV / Q000032:analysis*; D007425:Intracellular Membranes / Q000201:enzymology* / Q000648:ultrastructure; D007700:Kinetics; D008928:Mitochondria / Q000201:enzymology*; D008929:Mitochondria, Heart / Q000201:enzymology* / Q000648:ultrastructure; D013367:Submitochondrial Particles / Q000201:enzymology* / Q000648:ultrastructure
chemical_list: D003576:Electron Transport Complex IV