Figure 7.

Time course of Na⁺ uptake into reconstituted proteoliposomes. Na⁺ uptake into proteoliposomes was measured in 20 mM Tris-HCl pH 7.6 containing 5 mM MgCl₂ and 5.7 mM ²²NaCl (80 μCi mmol^-1) at times indicated in the presence (closed circle) and absence (open circle) of 4 mM ATP and in the presence of 4 mM ATP with 0.05 mM CCCP (closed square), 100 mM KNO₃ (open square), 0.1 mM monensin (closed rhombus), 0.01 mM gramicidin D (closed triangle). Effectors were added at 10 min before starting the reaction with ATP.