FIG. 6.

Effect of respiratory chain inhibitors on the NADH-induced formation of organic radicals by the membrane-bound Na⁺-NQR. Membranes from the wild-type V. cholerae strain were mixed with 29 mM KCN (blue trace) or 0.5 mM HQNO (red trace). After 10 min, 9 mM Na₂NADH was added, and the samples were frozen in liquid N₂. Black trace, membranes reduced with NADH in the absence of inhibitor. EPR conditions: microwave frequency, 9.674 GHz; modulation amplitude, 0.5 mT; microwave power, 1 mW; temperature, 70 K.