Figure 3.

Electrocatalytic reduction of hydrogen peroxide at a PGE electrode with S134P/V135K G. sulfurreducens CcpA adsorbed onto the graphite electrode surface. (A) Voltammogram collected for S134P/V135K with 25 µM peroxide in the cell solution. The dotted voltammogram is the baseline before the addition of peroxide. The black dotted vertical lines represents the catalytic potentials for S134P/V135K while the red dashed line shows the P. aeruginosa CcP (−70 mV) catalytic potential. (B.) Voltammograms collected for increasing concentrations of peroxide in the cell solution. (black = 5 µM, red = 10 µM, orange = 20 µM, purple = 40 µM, blue = 50 µM) The inset shows the calculation of K_m for voltammograms collected at a specific pH. (Experimental conditions: pH 7, scan rate = 20 mV/s, rotation rate = 1000 rpm.)