Figure 4.

Effects of pH (a) and temperature (b) on the robustness of ficin and HRP. 1.0 mg mL⁻¹ ficin and 1.0 μg mL⁻¹ HRP were first incubated at pH 1–14 for 2 h or 0–90 °C for 2 h. And then they were diluted to 0.10 μg mL⁻¹ (ficin) or 0.10 ng mL⁻¹ (HRP) to test the peroxidase activities under optimal conditions (20 mM PBS buffer, pH 5.0, 35 °C, 0.80 mM H₂O₂ and TMB). For each curve, the maximum point was defined as 100% and error bars represent the standard deviations of three independent experiments.