FIGURE 4.

Impedance spectra of CcO embedded in a ptBLM recorded at a bias potential of +200 mV versus NHE, as a function of the concentration of reduced cyt c (a), black (0 M), red (2.3 × 10⁻⁴ M), green (5.6 × 10⁻⁴ M), blue (8.4 × 10⁻⁴ M), magenta (1.07 × 10⁻³ M), cyan (1.28 × 10⁻³ M), and orange (1.6 × 10⁻³ M). Spectra were fitted using the equivalent circuit shown in Fig. 3 d. Resistances thus obtained were plotted versus the concentration of cyt c (b). The decrease is considered in terms of proton transfer due to the activation with reduced cyt c.