Partial Resolution of the Enzymes Catalyzing Oxidative Phosphorylation

Abstract 1. Evidence has been presented in this paper which greatly strengthens the suggestion that the spherical particles lining the inner membranes of mitochondria are the morphological representations of coupling factor 1 (ATPase). 2. With tritum-labeled ATPase it was shown that treatment of reconstituted particles with 2 m urea leads to a release of radioactivity which corresponded to the disappearance of the inner membrane spheres. 3. Certain salts, e.g. KI or KSCN were shown to facilitate the cold inactivation of ATPase in mitochondrial particles and to eliminate the inner membrane spheres. 4. Studies of the structural properties of reconstituted preparations of oligomycin-sensitive ATPase revealed characteristic fragments of membranes with inner membrane spheres. These preparations were essentially colorless and contained negligible amounts of respiratory enzymes. 5. A role of phospholipids in the organization of the membranous fragments was demonstrated.