FIG. 1.

(A) EST2 esterase and thioesterase activities as a function of pH. pNP-hexanoate (100 μM) and S-methyl thiobutanoate (20 mM) were used as the substrates. The buffers used were sodium citrate (pH 4.0 to 5.5), sodium phosphate (pH 5.5 to 7.0), and Tris-HCl (pH 7.0 to 8.0). Assays were performed at 30°C. (B) EST2 esterase and thioesterase activities as a function of NaCl concentration. pNP-hexanoate (100 μM) and S-methyl thiobutanoate (20 mM) were used as the substrates. Assays were performed at 30°C and pH 7.5. The activity is expressed relative to the activity without salt.