Catalase decomposes hydrogen peroxide into which products?

• A. Oxygen
• B. Water
• C. Hydroxyl radical
• D. Water and Oxygen

Answer: (D)

Catalase detoxifies hydrogen peroxide by converting it into water and molecular oxygen through a rapid dismutation reaction. The reaction is 2 H2O2 → 2 H2O + O2, so both water and oxygen are produced. That makes water and oxygen the correct description of the products. Producing only oxygen would miss the water formed, and producing only water would miss the oxygen produced. Hydroxyl radical isn’t formed in this enzyme’s action, since catalase provides a safe path to break down H2O2 without generating radical species. In the oral environment, many microbes encounter hydrogen peroxide, and catalase helps them survive by removing this oxidant and yielding harmless water and oxygen.