Enzyme Catalysis with Catalase
Key Notes From Lab Handout
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Enzyme: Catalase (from beef liver)
Substrate: H2O2 (hydrogen peroxide)
Stop Reaction: use sulfuric acid (H2SO4)
Quantify Amt. of H2O2 left: titrate in KMnO4
(potassium permanganate)
• Baseline: Starting total amount of H2O2
• FOUR ways enzyme activity can be altered:
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Salt concentration (salinity)
pH (acid/base concentration)
Temperature
Activators & Inhibitors
Lab #3- Enzyme Catalysis w/Catalase
Three Parts to the lab:
• Establish Baseline Amount of H2O2
• Uncatalyzed Decomposition of H2O2
• Time Trials w/Catalase to determine Rxn rate
• Procedure:
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10 ml H2O2 in a beaker
1.0 ml (H2O or Catalase)
10 ml 1 M H2SO4
Mix well
Take a 5 ml sample and titrate in KMnO4
Read Initial and final measurements on buret
Record Data
Uncatalyzed data
• Final reading: 11.2 ml
• Initial reading: 8.1 ml
• Amount of KMnO4: 3.1ml
Sample Data Set I
Amt.
KMnO4(ml)
10
sec
30
sec
60
sec
90
sec.
120
sec.
180
sec.
360 sec
Baseline
4.4
4.4
4.4
4.4
4.4
4.4
4.4
Final reading
12.0
15.3
17.4
23.1
24.4
11.5
11.6
Initial Reading
7.8
12.0
15.3
21.3
23.1
10.6
11.5
Amount KMnO4
4.2
3.3
2.1
1.8
1.3
0.9
0.1
0.2
1.1
2.3
2.6
3.1
3.5
4.3
used
Amount of H2O2
used
Sample Data II
Amt. KMnO4(ml)
10 sec
30 sec
60 sec
90 sec.
120 sec.
180 sec.
360 sec
Baseline
3.4
3.4
3.4
3.4
3.4
3.4
3.4
Final reading
8.6
10.2
11.2
12.2
11.5
11.6
11.6
Initial Reading
6.1
8.6
10.2
11.6
11.2
11.5
11.6
Amount KMnO4 used
2.5
1.6
1.0
0.6
0.3
0.1
0.05
(one drop)
Amount of H2O2 used
0.9
1.8
2.4
2.8
3.1
3.30
3.35
Conclusion Questions to Consider
1) Determine the amount of H2O2 in moles using the
chemical equation on pg. 22 and your amount of
H2O2 after 180 sec.
2) From Question #6, Choose two factors that can
affect the rate of enzyme-catalyzed reaction of
Catalase. Draw a predicted graph for each
reaction.
3) Name two organisms that could be used to
determine the reaction rate of an enzyme.
4) List two major sources of error and one suggestion
on how to improve the lab. What would you do
differently?