... efficiencies (the ratio of cathodic current in the presence and absence of substrate) using the values computed by Nicholson and Shain, and plotted vs. the inverse of the scan rate. The plotsyielded ... CoCl2,0.6andNa2B2O7,0.1. The optical density, the concentrations of nitrate [17] and nitrite [18], the pO2 and the pH of the medium weremonitored, and the composition of the gaseous phase in ... center of the enzyme. These modifications may beattributed to either the presence of the substrate and/ or aproduct in the vicinity of the T2Cu active center rather thanto disruption of this...