Fig. 5.

Membrane potential generation (ΔΨ) during the oxygen reaction of the Glu-278–Gln variant as detected by time-resolved electrometry. The experimental data shows the mean of three experiments (black) and are plotted together with the theoretical fit (gray). Conditions were: Mops-KOH, 100 mM (pH 7); hexaamineruthenium, 100 nM; glucose, 50 mM; catalase, 0.3 mg/ml; glucose oxidase, 3 mg/ml; CO, 100%. The reaction was started by a laser flash 1.4 s after the beginning of the injection of 100 μl of oxygen-saturated buffer. (Inset) The same trace together with the potential generation upon CO photodissociation without oxygen addition on a shorter time scale. The experimental traces were scaled by the amplitude of CO photodissociation phase to match the WT enzyme.