Catalase Enzyme Lab
Catalase Enzyme Lab purpose: Explore how changing the
environmental conditions of an enzyme affect the enzymes’ activity. In
this lab the enzymes’ activity can be indirectly measured through
temperature changes which indicate a release or intake of heat energy
from the chemical reaction which the enzyme is catalyzing.
Catalase Lab Background:
of catalase enzyme so – the catalase enzyme for this lab will be
extracted from chicken liver. All enzymes including Catalase enzyme
only fold into their active shape under specific environmental
conditions. An enzymes shape can be denatured by changes in
temperature, pH and salt concentration. Why? Because the all
changes interfere with the hydrogen bonds that help keep the enzyme
folded properly (see figure3).
Figure 1
catalase enzyme
2 Hydrogen peroxide
2 water + oxygen + heat energy
Hydrogen
Peroxide
Hydrogen
Peroxide
Oxygen gas – O2
This is the Catalase
enzyme in standard
water environment
Many cells produce Hydrogen peroxide as a toxic by product of their
metabolic reactions. Cells also produce catalase enzyme which assists
in the breakdown of hydrogen peroxide into harmless water and
oxygen gas (see figure 1). This reaction is exergonic -- energy
Products:
releasing (see figure 2).
Water and Oxygen gas
When you pour hydrogen
Fig. 2
peroxide on a cut the
catalase enzyme released
Reactant:
out of your damaged skin
Hydrogen
Peroxide
cells and from your blood
stream spead up
Energy released in the
the break down of
form of Heat
hydrogen peroxide and the
observed bubbling is
from the product oxygen.
The liver is a good source
This is the denatured
Catalase enzyme in
Acidic environment
Figure 3: cartoon illustration comparing Standard Catalase enzyme to Acidified
Catalase enzyme
Cell Biology State standard 1b
Students will learn that enzymes are Proteins that catalize( speed up)
chemical reactions without being used up
Students will learn that enzyme’s activity depends on temperature and pH
(acidic or alkali) conditions of their environment
Catalase Enzyme Lab Guide
catalase enzyme
2 Hydrogen peroxide
2 water + oxygen + heat energy
Results Data Table:
Procedure:
1. Using a pencil, label one test tube HP for Control (hydrogen
peroxide alone), another test tube needs to be labeled NC
(catalase enzyme with no acid) and the final test tube AC (for acidified
catalase enzyme)
Temperature of
Temperature of 8ml of
8ml of Control
Hydrogen peroxide
(Hydrogen Peroxide) combined with ½ ml of
Normal Catalase
Time
(Sec)
Control
0 seconds
Temperature of 8ml of
Hydrogen peroxide
combined with ½ ml of
Acidified Catalase
NC with a pH of ____ AC with a pH of ____
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)
(Before Enzyme is added!
2. Make Acidified Catalase: In the mixing container prepare the
acidified Catalase by pippetting 2ml of Normal Catalase and 2ml of
Acetic acid together. Let sit for 5 minutes (continue on with step 3 will
not need until step 9)
30 seconds
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60 seconds
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90 seconds
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3. Use the Graduated cylinder to measure 8 ml of
Hydrogen peroxide into each test tube
120 seconds
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4. Gather the data on the control: Record the temperature of the HP
test tube of just hydrogen peroxide every 30 seconds for 120 seconds
5. Record the temperature of the NC (Normal catalase )test tube with
just the hydrogen peroxide alone.
6. Leave the thermometer in the NC test tube and using the pipette to add
½ ml of Catalase to the NC test tube.
7. Swirl the NC test tube to ensure that the enzyme is mixed with the
hydrogen peroxide.
8. Record the temperature every 30 seconds for 120 seconds.
Conclusion Questions:
1. How did the Acetic acid affect the catalase enzyme (what did it do the structure of
the enzyme and what was the temperature)?
2. Did the temperature make a difference in the level of bubble activity in the tests
you did?
3. 2H2O2
2H2O + O2 is the chemical equation of the process you witnessed in
this lab. What were the bubbles in this experiment made of?
4. What temperature was catalase most reactive? Mammals internal body
temperature is close to 370C. How would body temperature affect catalse activity?
5. Hydrogen peroxide is a toxic molecule found in the cells of your body, why
would most human cells have the enzyme catalase.
9. Repeat steps 4-7 with the ACIDIFIED CATALASE in the AC test tube
6. Identify the sources of error in the experiment (what went wrong in the lab and
messed up your data)?