Effects of pH on activity and stability of cutinase-HlyAs and cutinase. (A) pH optimum. The samples were determined in the following buffer-potassium phosphate (pH 6.0-7.0) and Tris-HCl (pH 7.0-9.0). (B) pH stability. The samples were assayed after incubation 24 h at 37°C in various buffers-sodium acetate buffer(pH 4.0-6.0), potassium phosphate buffer (pH 6.0-7.0), Tris-HCl buffer (pH 7.0-9.0), and glycine-NaOH buffer (pH 9.0-11.0). ■, cutinase; ●, cutinase-HlyAs. The error bars show the standard deviations from three measurements.