Title : THE EFFECT OF PH ON THE ACTIVITY OF CATALASE
Aim : To study the effect of pH on the activity of catalase. Introduction :
Catalase, an enzyme found in many different tissues, catalyses the breakdown of hydrogen peroxide into water and oxygen. 2 H202 → 2H20 + O2
Hydrogen peroxide is a toxic substance that can be formed during aerobic respiration and catalase removes this product. The activity of catalase can be measured by finding the rate of oxygen release from hydrogen peroxide. Potato provides a suitable source of catalase and the pH is varied in this experiment using citric acid-sodium phosphate buffer solutions at pH values of 4.4, 5.2, 6.5 and 7.5. Catalase is an enzyme, a biological (organic) catalyst. Hydrogen peroxide is the substrate for catalase. It lowers the activation energy required for a chemical reaction, and therefore increases the rate of the reaction without being destroyed or altered during the process. The activity of enzyme is affected by the acidity or alkalinity of the solutions in which they act. If the environment of the enzyme is too acidic or too basic, the enzyme may irreversibly denature until it no longer has the shape necessary for proper functioning. In a cell, most enzymes function optimally at a pH that ranges from 6 to 8. Materials & Apparatus :
Potato discs, pH 4.4, pH 5.2, pH 6.5, pH 7.5 of buffer solution, hydrogen peroxide solution , water, plastic syringe, graduated pipette or syringe, stopwatch, boiling tubes, test tubes, bung which is connected to delivery tube. Procedure :
To prepare citric acid-sodium phosphate buffer solutions:
1. Solution A is 21g of citric acid H20 dm-3. Solution B is 28.4 g anhydrous disodium hydrogen phosphate (Na2HPO4) dm-3. Buffer solutions of each pH are prepared by mixing solutions A and B in the volume shown in table 1.
Conduct the experiment:
1. The apparatus is set up as shown in Figure 1.
2. 10 discs of potatoes which are evenly...
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