<P> Catalase is usually located in a cellular organelle called the peroxisome . Peroxisomes in plant cells are involved in photorespiration (the use of oxygen and production of carbon dioxide) and symbiotic nitrogen fixation (the breaking apart of diatomic nitrogen (N) to reactive nitrogen atoms). Hydrogen peroxide is used as a potent antimicrobial agent when cells are infected with a pathogen . Catalase - positive pathogens, such as Mycobacterium tuberculosis, Legionella pneumophila, and Campylobacter jejuni, make catalase to deactivate the peroxide radicals, thus allowing them to survive unharmed within the host . </P> <P> Like alcohol dehydrogenase, catalase converts ethanol to acetaldehyde, but it is unlikely that this reaction is physiologically significant . </P> <P> The large majority of known organisms use catalase in every organ, with particularly high concentrations occurring in the liver in mammals . One unique use of catalase occurs in the bombardier beetle . This beetle has two sets of liquids that are stored separately in two paired glands . The larger of the pair, the storage chamber or reservoir, contains hydroquinones and hydrogen peroxide, while the smaller, the reaction chamber, contains catalases and peroxidases . To activate the noxious spray, the beetle mixes the contents of the two compartments, causing oxygen to be liberated from hydrogen peroxide . The oxygen oxidizes the hydroquinones and also acts as the propellant . The oxidation reaction is very exothermic (ΔH = − 202.8 kJ / mol) and rapidly heats the mixture to the boiling point . </P> <P> Almost all aerobic microorganisms use catalase . It is also present in some anaerobic microorganisms, such as Methanosarcina barkeri . Catalase is also universal among plants and occurs in most fungi . </P>

Where do you find catalase in the body