Investigating pH Effects on Catalase Activity

Investigating the Effect of pH on Catalase Activity

• Catalase is an enzyme that breaks down hydrogen peroxide (H₂O₂) into water (H₂O) and oxygen (O₂).
• Buffer solutions resist changes in pH. Different solutions maintain different pH values.
• Hydrogen peroxide is a metabolic product toxic to cells. Catalase protects cells by breaking it down.
• Potato cells contain a high concentration of catalase.
• A method was used to extract catalase from potato cells:
  • A large potato was chopped small and placed into a blender with an equal amount of water.
  • This mixture was blended to release the catalase from the potato cells.
  • The potato debris settled to the bottom of the mixture.
  • The liquid extract was removed.
• The catalase extract's activity was then tested at different pH levels:
  • Using a syringe, 5 cm³ of potato extract was placed in a boiling tube.
  • 5 cm³ of a buffer solution (with a specific pH) was added to the boiling tube.
  • The mixture was shaken to combine the extract and buffer solution.
  • The mixture was left to settle for 5 minutes.
  • 5cm³ of 5% hydrogen peroxide solution was added to the reaction mixture.
  • A bung and delivery tube was placed in the boiling tube, connected to a beaker of water.
  • The number of oxygen bubbles produced by the reaction per minute was counted.
• The experiment was repeated using different pH buffers. The results are shown in a table with pH levels and the rate of reaction (measured in bubbles per minute).