Application

Catalase acts as a natural antioxidant to study the roles of reactive oxygen species in gene expression and apoptosis. It has also been used to protect against oxidative damage to proteins, lipids, and nucleic acids. Industrially, catalses have been used to remove hydrogen peroxide added to milk and cheese, in textile bleaching, and to examine its positive effects on the viability of DNA-repair mutants of E. coli.

Biochem/physiol Actions

Catalase catalyzes the degradation of hydrogen peroxide into water and oxygen. It can also react with alkylhydrogen peroxides, such as methylperoxide and ethylperoxide and the second H₂O₂ molecule can be replaced by methanol, ethanol, propanol, formate and nitrate as a hydrogen donor.

This product doesn′t need any activators, but it is inhibited by 3-amino-1-H-1,2,4 triazole, cyanide, azide, hydroxylamine, cyanogens bromide, 2-mercaptoethanol, dithiothreitol, dianisidnie and nitrate.

Caution

Solutions of catalse should not be frozen. Frozen solution will result in a 50-70% loss of activity.

Components

Catalase from bovine liver is a tetramer consisting of 4 equal subunits each with a 60 kDa molecular weight. Each of these subunits contains iron bound to a protoheme IX group. The enzyme will also strongly bind to NADP, where NADP and the heme group are within 13.7 angstroms.

Preparation Note

This product is an aqueous solution containing >30,000 units/mg protein. To remove the thymol preservative, the catalase crystals may be pelleted by centrifugation, the supernatant, discarded, the pellet resuspended in water, and then pelleted again. The enzyme is soluble in 50 mM potassium phosphate buffer at 1 mg/mL and pH 7.0.

Unit Definition

One unit will decompose 1.0 µmole of H₂O₂ per min at pH 7.0 at 25 °C, while the H₂O₂ concentration falls from 10.3 to 9.2 mM, measured by the rate of decrease of A₂₄₀.