Fig. 4.
An inhibitor of SDH (3-NPA) activates the channel, whereas 5-HD reverses this effect. (A) Effects of 3-NPA on K+ transport in proteoliposomes. The K+ transport was significantly activated by addition of 1 mM 3-NPA, whereas 5-HD reversed this effect. (B) A similar response to 3-NPA was noted in lipid bilayer. Microsomes from the M-fraction were incorporated into lipid bilayer, and single K+ channel activity was recorded in the absence of any modulator. After addition of 1 mM of 3-NPA, the Po increased ≈4-fold. Addition of 5-HD reversed this activation significantly. Closed and open current levels for all recordings are indicated by solid and dashed horizontal lines, respectively. (C) Summary of studies on 3-NPA in lipid bilayer.