Figure 4. Effect of different NADPH concentrations on the kinetics of diformazan formation in the superoxide-generating reaction xanthine-xanthine oxidase: 1 – 1.0 mM; 2 – 0.5 mM: 3 – control. Measurement conditions: 50 mM carbonate buffer, pH 10.2, containing 0.4 mM EDTA, 0.1 mM xanthine, 0.025 mM NBT, xanthine oxidase 11 μg protein/ml. Temperature 19°C.