ATP synthesis in Staphylococcus aureus cells during induction of membrane potentials and proton gradient

The dynamics of ATP synthesis in Staphylococcus aureus cells was studied during membrane potential induction and K+ gradient generation in the presence of valinomycin. The starting level of intracellular ATP was 0.05 mM. Valinomycin (30 micrograms/ml) caused an increment of the intracellular ATP level up to 0.25 mM. The protonophore uncoupler, m-chlorinecarbonylcyanidephenylhydrazonium, and the H+-ATPase inhibitor, N,N'-dicyclohexylcarbodiimide, effectively suppress ATP synthesis induced by valinomycin. No ATP synthesis occurs at K+ concentration of 200 mM. The transmembrane gradient formation results in the synthesis of a smaller amount of ATP (0.10 mM).