Energy coupling in lysolecithin-treated submitochondrial particles

Abstract

Lysolecithin, at a level of 1.2 mg per mg protein, completely suppressed active transport of K + and energized H + uptake in ETP H, as well as eliminating vesicular profiles as determined by electron microscopic examination of positively stained ultrathin sections. Nonetheless, lysolecithin-treated ETP H showed essentially complete retention of two coupled functions, namely, uncoupler-stimulated ATPase activity and uncoupler-stimulated NADH oxidase activity and partial retention of ATP-P i exchange activity and phosphorylation coupled to NADH oxidation. These results indicate that the capacity to generate a H + gradient or a K + gradient is not a prerequisite for energy coupling and that the basic postulate of the chemiosmotic hypothesis (1) is therefore invalid.