Figure 3

Effects of pH on activity and stability of purified  S  -HMGSH dehydrogenase. The following buffer solutions were used: 50 mM citrate-NaOH buffer (squares, pH 3–6), 50 mM phosphate buffer (triangles, pH 6–8) and 50 mM borate-NaOH buffer (circles, pH 8–10). The reaction was carried out at 35°C for 10 min at various pH values (open symbols). In pH stability experiments, the enzyme was treated at 25°C for 20 h at various pH values, and the activity remaining was measured under standard assay conditions (closed symbols).