Fig. 4: Anaerobic conversion between active and inactive CbA5H^WT monitored by PFE.

a Chronoamperograms recorded to analyze the kinetics of anaerobic (in)activation of CbA5H^WT by stepping between −0.31 and −0.21 V. The boxes along the abscissa depict the sequence of applied potential steps and the corresponding current response (black line). The plot also shows the best fits of models that consider the interconversion between two (green dotted line) or three (red dotted line) species. Experimental parameters: 5 °C, pH 7, 3000 rpm. b Dependence of the rate constants of the “AAI” model (A1 ↔ A2 ↔ H_inact) on potential and pH, based on the analyses of chronoamperograms recorded for CbA5H^WT at pH 10 (squares), 8.5 (triangle), and 7 (circle). Only k_react significantly depends on pH and electrode potential. Source data are provided in a source data file.