Catalase Assay Kit can be used to measure the activity of catalase (CAT), which catalyses the decomposition of hydrogen peroxide (H2O2) to water (H2O) and oxygen (O2). CAT activity is inhibited by ammonium molybdate. Any remaining H2O2 reacts with ammonium molybdate to produce a yellowish complex. The absorbance can be measured at 405 nm to determine the activity. The 96 tests size requires 100 tubes.