Factors Affecting Enzyme Activity

e studied the effect of temperature, enzyme concentration and pH on enzyme activity. The enzyme we studied was hydrogen peroxidase from a cow. The reaction converted hydrogen peroxide to water and oxygen and oxygen production was used as a measure of enzyme activity. We studied enzyme activity at temperatures of 9 C, 37 C, 41 C. It showed that at 9 C, there was almost no activity. The activity at 41 was 1.5X the activity at 37. The enzyme was tested using 1⁄2X, 1X and 2X enzyme concentration. Significant enzyme activity was seen at 1x enzyme concentration and the 1⁄2X enzyme concentration trial showed almost the same activity. The activity at 2X enzyme concentration was approximately 2 times that at 1X enzyme concentration. Finally, we tested the effect of pH on the enzyme with pH 7, pH 1 and pH 11. The enzyme activity was highest at neutral pH (7) and showed only 1/3 enzyme activity at pH 11while pH of 1 showed no enzyme activity. Introduction: Enzymes are catalysts or chemical agents that speed up chemical reactions without being consumed by the reaction (Reece et al. 2010). Most enzymes are proteins that function to reduce activation energy in chemical reactions (Petersen and Anderson 2005). Enzymes work on reactants called substrate; the enzyme attaches to the substrate and then the enzyme converts the substrate to products while the enzyme remains unaffected (Reece et al. 2010). Enzyme activity can be affected by environmental factors (Petersen and Anderson 2005). Temperature is one environmental factor that can affect enzyme activity (Conant 2012). Another factor that affects enzymes is pH (Leake and Read 1990). In this lab, we will be studying the effects of temperature, enzyme concentration and pH on the enzyme, hydrogen peroxidase that is found in all aerobic cells and functions to decompose hydrogen peroxide (Petersen and Anderson 2005). Materials and methods: A strip of filter paper was dipped into a cow liver homogenate for 10 seconds and then placed in a chamber. 20 mL of 1.5% H2O2 was added to the chamber and the chamber was plugged with a stopper and then placed in a water bath. After 5 minutes, a 50 mL graduated cylinder filled with water was overturned over the chamber to flow the H2O2. Measurements of oxygen released were taken at 5 second intervals for one minute for each trial. This experiment was done with three different variables: Temperature, enzyme concentration and pH. The temperatures tested were: 9 C, 37 C, 41 C. The enzyme concentration was done using 1⁄2 strip, 1 strip and 2 strips of filter paper (representing 1⁄2X, 1X and 2X enzyme concentration) keeping the temperature at 37 C. The pH test was done using 1 strip with 5 drops of 50% HCl added to the H2O2 to produce a pH of 1. Another pH test was performed by adding 5 drops of 50% NaOH to the H2O2 to yield a pH of 11. The third trial was kept at pH 7. The temperature for the pH trials was at 37 C. W 1 Eed: Factors Affecting Enzyme Activity Produced by The Berkeley Electronic Press, 2013