EN
Energetics of 109Cd efflux in resting cells of cadmium-resistant Staphylococcus aureus 17810R was assayed in 1 or 100 mM potassium/sodium phosphate buffer, pH 7 (PB). Experiments with the use of inhibitors and ionophores showed that Cd2+ extrusion in this organism required ATP and either a pH gradient (ApH) in 1 mM PB or membrane potential (A\y) in 100 mM PB. The role of high phosphate ion concentration in A\|/-dependent Cd2+ efflux is discussed.