Figure 4.

Effects of pH and temperature on the activity of the purified recombinant PelN. (A) The optimal pH was determined at 45°C in 50 mM Tris–HCl buffer (pH 7.1–9.0, ■), 50 mM glycine–NaOH buffer (pH 9.0–11.0, ○), and 50 mM Na₂HPO₄–NaOH buffer (pH 11.0–12.0, ▲); (B) the optimal temperature was determined at pH 9.8. The highest specific activities in both the assays were respectively used as references (100%). Error bars represent ± SD (n = 4).