The catalase (CAT) activity was measured using the OxiSelect™
Catalase Assay Kit (Cell biolabs, Inc.). The quinoneimine dye
coupling product is measured at 520 nm, which correlated to the
amount of hydrogen peroxide remaining in the reaction mixture.
The CAT activity was expressed as unit/mg protein and one unit of
CAT is the amount of enzyme that will decompose 1 mMof H2O2 per
minute at 25 C.