Non disponible en dehors du Royaume-Uni et de l'Irlande

Analysis Note

Protein determined by biuret

Application

Catalase from Sigma has been used as a positive control during the functional characterization of Clostridium difficile spore coat proteins.

Biochem/physiol Actions

Catalase catalyzes the decomposition of hydrogen peroxide into water and oxygen. Each subunit of the tetramer contains iron bound to a protoheme IX group. The enzyme also strongly binds NADP, which is in close proximity to the heme group. Isoelectric point is found to be 6.5. Optimum pH for catalytic activity is 7.0. The enzyme activity is inhibited by 3-amino-1-H-1,2,4 triazole, cyanide, azide, hydroxylamine, cyanogen bromide, 2-mercaptoethanol, dithiothreitol, dianisidine, and nitrate. Incubation of catalase with ascorbate or ascorbate/Cu²⁺ results in degradation of the catalase molecule.

Caution

Freezing of solutions is not recommended.

Packaging

10, 25 mg in glass bottle

Physical form

Suspension in 3.2 M (NH₄)₂SO₄ solution, pH 6.0

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.