Figure 6. A. Typical traces showing the reduction of cyt bH in N279Y strain at differnt redox potentials. As the potential is lowered, the quinone pool becomes reduced, and the concentration of substrate QH2 increases. The increased rate reflects the second-order reaction at the Qo-site, and the saturation behavior indicates the approach to a fully occupied site when the pool is only partially reduced.

B, C, D. Plots (1 / rate v. 1 / [quinol]) from which Km and Vmax were calculated.