Electron Transfer in Catalases and Catalase-Peroxidases

International audienceCatalases (EC 1.11.1.6) are enzymes that catalyze the disproportionation of hydrogen peroxide into water and molecular oxygen by means of a heme iron or a dimanganese active site. They are crucial metalloproteins regulating the cellular concentration of hydrogen peroxide, which has a concentration-dependent dual role in cell signaling and oxidative stress.Catalase-peroxidases, also named KatGs from the encoding katG gene, are heme-containing oxidoreductases capable of both the disproportionation of hydrogen peroxide and the oxidation of substrates via high-valent heme intermediates. KatGs also generate superoxide via an oxidase reaction and activate the antitubercular prodrug isoniazid (INH) through its conversion to isonicotinyl-NAD