[Formation of differences in the electric potentials of the membrane vesicle in Staphylococcus aureus]

Membrane vesicles isolated from Staphylococcus aureus cells by ultrasonication possess the NADH-, succinate-, and malate oxidase activities, contain cytochromes a and b and have the lipid/protein ratio of 0.12-0.24. Energized membrane vesicles absorb permeant anions of tetraphenylborate and phenyldicarbaundecaborane. This results in the electric field generation with a "plus" sign on the inner side of the membranes. The generation of the membrane potential occurs in response to the addition of a respiratory substrate (NADH, malate, or succinate) and is inhibited by electron transfer inhibitors, such as rotenone, 2-N-nonyl-4-oxyquinoline-N-oxide, cyanide and the protonophore uncoupler, M-chlorinecarbonylcyanidephenylhydrazonium. The generation of the membrane potential takes place during ATP hydrolysis and in the course of the transhydrogenase reaction. The data obtained suggest the similarity of energization systems of St. aureus and those of animal mitochondria.