Fig. 7. (A) CVs (10 mV/s) of 8OH/8NH₃⁺ (90/10) modified gold electrode in buffer, incubated with 0.5 μM CymA before (grey line) and after (black line) addition of POPC vesicles containing 1.0% (w/w) MQ-7. The dashed line is a CV before incubation with CymA. (Insert) idem, for (black line) pure 8OH and (grey) pure 8NH₃⁺ modified surfaces. (B) Black line: The maximum current determined at about −0.2 V vs SHE from CVs such as shown in (A) as a function of the relative amount of 8NH₃⁺ on the surface, which is given as 8NH₃⁺/(8NH₃⁺ + 8OH). Grey line: k_CymA (= the activity per CymA enzyme) as a function of the relative amount of 8NH₃⁺ on the surface.