The supernate (0.1 ml) was reacted at room temperature (∼22 °C) with 2.9 ml of 11 mM H2O2 in phosphate buffer, and the reaction (H2O2 loss) was monitored by measuring the absorbance at 240 nm during the initial 30 s.
One unit (U) of catalase was defined as the amount of extract needed to decompose 1 mmol of H2O2 per min