Figure 1.

Screening of the inhibition potentials of tested hydroxynaphthoquinones (HNQ) on the oxidase reduction activity of purified E. coli cytbo₃ (white) and bd‐I (light gray) oxidase. Inhibition assay using HNQs at 250 μM in the presence of 200 μM ubiquinone‐1 and 5 mM dithiothreitol. Oxygen reduction activity was calculated from oxygen consumption rates at 30 nM enzyme concentration at RT for each experiment. 100 % activity=adding corresponding volume of EtOH. KCN (20 μM) and HQNO (250 μM) represent positive inhibition controls for cyt bo₃. The data are mean values of three independent experiments ± standard deviation.