FIGURE 4.

Phosphorylation levels at 150 mm and 600 mm Na⁺ relative to the maximum level obtained in the presence of oligomycin. Phosphorylation was carried out for 10 s at 0 °C in 20 mm Tris (pH 7.5), 3 mm MgCl₂, 1 mm EGTA, 10 μm ouabain, 2 μm [γ-³²P]ATP, and 150 (black columns) or 600 (gray columns) mm NaCl. The phosphorylation level is shown relative to that obtained at 150 mm NaCl in the presence of oligomycin (20 μg/ml). Standard errors are indicated by error bars. WT, wild type.