FIGURE 6.

NADH-dependent ²²Na⁺ export from inverted membrane vesicles. For sodium transport, membrane vesicles (3 mg) were incubated in 1 ml of 100 mm Tris (pH 7.5), 5 mm MgCl₂, 2 mm NaCl, 100 μm ferredoxin, 2 mm DTE, and 2 μm resazurin in a nitrogen atmosphere. The reaction was started by the addition of 2 mm ATP. In the assay with NADH (■), the electron carrier was added at a concentration of 5 mm. In the assay without NADH (♦), water was added in an equal volume. The data shown are representative of three experiments using independent inverted membrane vesicle preparations.