Action of catalase enzyme. Hydrogen peroxide (H202) decomposition being accelerated by the catalase enzyme found in raw liver (liver seen at bottom of flask). An enzyme is a biological catalyst, increasing reaction rates without itself reacting or changing. The hydrogen peroxide is breaking down into oxygen (producing bubbles) and water. The equation for this reaction is: 2H202 ----> 2H20 + O2 Catalase (or hydrogen peroxide oxidoreductase) protects cells from the toxic effects of hydrogen peroxide, which is a powerful oxidizer produced as a biochemical byproduct. Peroxide is used as a bleach and as a reagent in the chemical industry.