Figure 4.

Potential gradient effect on Ca²⁺ transport across inner-envelope vesicles. Ca²⁺ influx into inner-envelope vesicles prepared by extrusion was monitored under varying magnitudes of ΔΨ generated by adjusting the KCl and choline chloride solutions used in Figure 3. The intravesicular [K⁺] was maintained at 110 mm. The ΔΨ was varied by changing the external [K⁺]. Inner-envelope vesicles (15 μg of protein) were incubated with 2 nm valinomycin for 30 min before each experiment.