What is Catalase?
Enzymes are very large and complex organic molecules that are synthesized by the cell to perform very specific functions. These biological catalysts are important because they speed up the rate of the reaction they catalyze that would otherwise be too slow to support life. Catalase is an enzyme present in the cells of plants, animals and aerobic (oxygen requiring) bacteria. It promotes the conversion of hydrogen peroxide, a powerful and potentially harmful oxidizing agent, to water and molecular oxygen.
2H2O2 to 2H2O + O2
Catalase also uses hydrogen peroxide to oxidize toxins including phenols, formic acid, formaldehyde and alcohols.
H2O2 + RH2 to 2H2O + R
Where is it found and what does it do?
Catalase is located in a cell organelle called the peroxisome. Peroxisomes in animal cells are involved in the oxidation of fatty acids, and the synthesis of cholesterol and bile acids. Hydrogen peroxide is a byproduct of fatty acid oxidation.
White blood cells produce hydrogen peroxide to kill bacteria. In both cases catalase prevents the hydrogen peroxide from harming the cell itself. 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 the nitrogen molecule N2 to reactive nitrogen atoms). Hydrogen peroxide is produced as an intermediate during these chemical processes and must be removed to prevent damage to cellular machinery. Aerobic (oxygen requiring) bacteria produce hydrogen peroxide as a byproduct of metabolism. This fact is used when identifying bacteria. If hydrogen peroxide is added to a bacterial colony and bubbles are produced, this is evidence of oxygen production and confirms that the colony is aerobic.
Prokaryotes, organisms like bacteria that lack a nuclear membrane, also lack membrane bound organelles such as peroxisomes. Antioxidant enzymes like catalase...