**3.4 Catalase activity**

The catalase (CAT) activity was assessed according to Aebi [41]. The CAT induced decomposition of hydrogen peroxide (H2O2) into water and oxygen. The rate of disintegration is proportional to the concentration of CAT activity. The CAT activity was determined by measuring the change in absorbance of H2O2 and sample mixture. Briefly, the CAT assay was performed in duplicate; 150 μL H2O2 was added to 20 μL of sample. Readings were determined by using a spectrophotometer (Thermo Electron Corporation, Multiskan Spectrum, USA) at 240 nm wavelength. The CAT activity was expressed as μmol/mg of protein.
