FIGURE 5.

Inhibitory effects of Reactive Blue-2 and ubiquinol on NADH-UQ₁ reductase activity of Ndi1. A, structures of UQ₁, UQ₁H₂, and several inhibitors for NQO1. B, NADH-UQ₁ reductase activities were measured in the presence of increasing concentrations of RB-2 (closed circle). The NADH-UQ₁ reductase activity was corrected for nonspecific inhibition using the value in the presence of 1 nm RB-2 as 100% activity (open circle). 100% activity was 900 μmol of NADH oxidized/min/mg of Ndi1. Each value and vertical bar represent the mean ± S.E.