FIGURE 4.

The relative specific activities of five catalases under different pH and temperatures. Specific activity of each catalase at 30°C and pH 7.4 was set as 100%. The catalytic activities at different pH values were determined at 30°C using several buffer systems: 50 mM NaAc-HAc, pH 4.0 – 6.0 (up triangle), 50 mM NaH₂PO₄-Na₂HPO₄, pH 6.0 – 8.0 (circle), and 50 mM Na₂CO₃-NaHCO₃, pH 8.0 - 10.0 (down triangle). Activities at different temperatures were determined at pH 7.4.