AP Biology Lab: Catalase (Enzymes)

Abstract In this laboratory exercise, studies of enzyme catalase, which accelerates the breakdown of hydrogen peroxide into water and oxygen. The purpose was to isolate catalase from starch and measure the rate of activity under different conditions. The laboratory was also conducted in association with a second laboratory that measured the effects of an inhibitor on the enzymes.
Changes in temperature and pH along with Substrate Concentration and Enzyme Concentration were the conditions tested in the experiment.
Four AP Biology classes performed this experiment and the data presented in this report will reflect the averages of said classes. In the later discussion sections, it will become …show more content…

Rate vs.pH 2A 3A 4A 4B Average
NaOH - 12 0.16 0.09 0.062 0.15 0.12
Malox - 9 0.22 0.13 0.057 0.13 0.13
Hydrogen Peroxide - 7 0.17 0.16 0.062 0.16 0.14
Vinegar - 3 0.1 0.19 0.051 0.11 0.11
HCL - 1 0.09 0.24 No Rx 0.1 0.108

The rate peaked at a pH of 7 and then decreases outward.

Rate vs. Temperature 2A 3A 4A 4B Average
0 degrees C 0.67 0.09 0.66 0.18 0.4
5 degrees C 1 0.13 0.84 0.13 0.46
25 degrees C 0.5 0.16 0.02 0.22 0.11
40 degrees C 0.22 0.19 0.19 0.1 0.18
60 degrees C 0.33 0.24 0.05 0.08 0.175

At the lower temperatures, the activity rate was high but then at 25oC, the rate dropped. After that the rate seems to be increasing toward another drop-off point.

Inhibitor Effects 2A 3A 4A 4B Average
Control 0.2 0.095 0.52 0.115 0.23
Hydroxylamine 0.0083 0.001 0.008 0.004 0.005

The inhibitor slowed the reaction to almost a complete stop.

Conclusion In conclusion, the classes have come to the result that each enzyme has a specific set of conditions that must be met for optimum activity. The changes in the temperature, pH, substrate concentration and enzyme concentration, cause fluctuations in the activity rate of the enzyme. Also, if the temperature or pH is too high or too low, then the