Catalase Lab

Effects of Enzyme Catalysis of H2O2 by Catalase

Report by: Timmy Lin (#269164729)
October 17, 2011
Mr. Rienzi AP Biology

Problem: Measuring the effects of Catalase enzymes on hydrogen peroxide decomposition. Measuring the rate of the reaction when hydrogen peroxide and Catalase are mixed at the same ratio for different time (10, 20 30 60 120 180 360 seconds).

Background: Enzymes are biological catalysts that carry out cellular metabolic processes with the ability to enhance the rate of reaction between. They are large proteins made up of several hundred chains of amino acid. In an enzyme-catalyzed reaction, the substance to be acted upon, or substrate, binds to the active site of the enzyme. The enzyme and substrate are held together
Use 10mL pipette to slowly add KMnO4 until solution turns persistent pink or brown color 7. Repeat Steps 1-6 for time intervals of 30,60, 120, 180, and 360 seconds

Test of Catalase Activity 1. Cut 1mL (cm3) of potato and macerate it. 2. Prepare 50mL glass beaker with 10mL of H2O2 3. Place 1mL potato into glass beaker and record results 4. Repeat step 2 5. Place boiled 1mL of boiled potato into 50mL beaker of solution

Data KMnO4(mL) | Time(seconds) | | 10s | 30s | 60s | 120s | 180s | 360s | A. Baseline | 3.5 | 3.5 | 3.5 | 3.5 | 3.5 | 3.5 | B. Final Reading | 7.5 | 7.5 | 8 | 8 | 8 | 7.5 | C. Initial Reading | 5 | 5 | 5 | 5 | 5 | 5 | D. Amount of KMnO4 Consumed | 2.5 | 2.5 | 3 | 3 | 3 | 2.5 | E. Amount of H2O2 Used | 1 | 1 | .5 | .5 | .5 | 1 |

Baseline Calculation
Final Reading of Pipette 6.5mL
Initial Reading of Pipette 3mL
Baseline 3.5mL

Rate of reaction: Time | Calculation(Amount decomposed/Time) | Rate | 10s | 1/10 | .1 mL/s | 30s | 1/20 | .05 mL/s | 60s | .5/30 | .0167 mL/s | 120s | .5/60 | .008 mL/s | 180s | .5/60 | .008 mL/s | 360s | 1/180 | .005 mL/s | Average Rate | | .031mL/s
As the data is then changed into the rate of reaction based on time, we can tell that the rate of disappearance is slowly decreasing. To get a even clearer idea on what our data looked like, I put the rate of disappearance of H2O2 into a time plot which illustrates rate over time. We can now see the image that the graph is exponentially decreasing at a rapid rate as the time of the mixing increases. The average rate of reaction for our results is .031 mL/s. The data we see is an result of decreasing concentration of substrate. When the catalase is first introduced for 10seconds, the rate of reaction was highest because that was when substrate and enzyme concentration stayed the highest. As the experiment is prolonged, substrate concentration will only decrease as it is limited but the enzymes will continue to catalyze the lower concentration which leads to a lower rate. The amount of H2O2 consumed in the time course determination test never exceeded the baseline because it is expected that the baseline reacts to