Please do not write
on this handout.
Lab 2 Enzyme Catalysis
Pre-Lab Questions:
1. How will you calculate the baseline rate for catalase?
2. What are possible factors that affect enzyme activity that you can test in this lab?
3. Choose one of the factors and write a hypothesis for that factor using an “If…then…” format.
4. Looking at the list of available materials, how could you design an experiment to test the effect of…
a. Substrate concentration?
b. Enzyme concentration?
c. pH?
d. Temperature?
e. Salinity?
Introduction (continued):
In this lab, you will calculate the rate of catalase activity by measuring the rate of substrate (O2) production.
Filter paper discs soaked in catalase will be placed at the bottom of a beaker containing hydrogen peroxide
(H2O2). As catalase starts to break down H2O2 to form H2O and O2, the oxygen will form bubbles and cause
the filter paper discs to rise to the top. The speed with which O2 bubbles cause a paper disc to rise indicates
the relative speed of the reaction. You will calculate the rate of catalase activity by measuring the distance
traveled by the filter paper disc and the time it took for the disc to reach the surface (rate = distance/time).
Materials Available:
• Hydrogen peroxide, ___%
• Catalase (Baker’s Yeast)
• Filter paper
• Hole punch
• Various sized beakers, graduated cylinders, test
tubes, pipettes
• Tweezers
• Rulers
• Stopwatch
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Distilled water
Hydrochloric acid (HCl)
Sodium hydroxide (NaOH)
pH paper (possibly pH meters)
Salt
Hot plates
Ice
Thermometers
Procedure for Measuring Baseline Rate of Catalase:
1. Use a hole punch to make a disc of filter paper.
2. Fill a small beaker with hydrogen peroxide solution. Using a ruler, measure the depth of the hydrogen
peroxide solution in millimeters. (Hint: It is advised that you use the same sized beaker and similar amount of
hydrogen peroxide for your entire investigation.)
3. Using tweezers, soak the filter paper disc in the yeast/catalase solution for 10 seconds. Blot with paper
towel to remove excess catalase.
4. Using tweezers, place the soaked filter paper disc at the bottom of the beaker containing hydrogen
peroxide. Begin timing when the disc touches the bottom of the beaker.
5. Stop timing when the disc reaches the surface.
6. Repeat the procedure 2 more times.
Baseline Data Table:
Trial
Distance Disc
Traveled (mm)
Time (seconds)
Rate (mm/sec)
1
2
3
Average
Develop your own procedure & data tables for the variable your group will be testing. Graph your data.
Discussion Questions:
1. What was the enzyme used in this lab?
2. What was the substrate used in this lab?
3. According to your data, what is the optimal temperature/pH for the enzyme catalase? How do you
know this?
4. What happened to the rate when the temperature/pH was above or below the optimal?
5. At certain measurements, you may have gotten a rate of zero. Why was the enzyme not functional at
those measurements?
6. Long Answer: What improvements would you make to your experimental design if you had more time
and could do your experiment again? What were some sources of possible errors or inconsistencies?
Lab 2 Enzyme Catalysis – Lab Notebook Contents
 Pre – Lab Questions [stamped]
 Baseline Data Table
 Procedure Flow Chart for your group’s variable (materials needed) [stamped]
 Effect of temperature/pH Data Tables
 Graph - Effect of temperature/pH on catalase rate
 Discussion Questions
Lab 2 Enzyme Catalysis – Mini-Poster Requirements
 Title – the question your group is answering
 Introduction – describe background information needed to understand the experiment
 Hypothesis – “If…then…” format for the variable your group is testing
 Procedure
 Data Tables
 Graph – Effect of temperature/pH on catalase rate
 Conclusion
 Visuals