Estimation of the pH and temperature optima of SBcas3.3. a. Effect of pH on the relative activity of SBcas3.3. The ability to hydrolyse azocasein was assayed at 50°C in different buffers (♦) 50 mM Na-acetate buffer pH 5–6, (■) 50 mM Tris–HCl buffer pH 6–10, (▲) 50 mM glycine-NaOH buffer pH 8–12. b. Temperature-dependent activity of SBcas3.3, measured at pH 9 with azocasein as substrate. No error bars are indicated in these graphs (the standard error of the mean was always below 2%).