Enzyme Action: Testing Catalase Activity
1. Obtain and wear goggles.
2. Prepare the pressure sensor for data collection:
- Plug the pressure sensor into Port 1 of the Serial Box Interface
- Attach the heavy-wall plastic tubing of the rubber-stopper
assembly to the end opening of the 3-way valve of the Pressure
3. Prepare the computer for data collection.
4. Leave the side valve of the pressure sensor open until Step
If your pressure sensor has a plastic valve, align the blue handle
with the arm that leads to the pressure sensor.
Test the Effect of Enzyme Concentration
5. Place four test tubes in a rack and label them 1, 2, 3, and
4 Drops. Partially fill a beaker with tap water for use in Step
6. Add 3 mL of water and 3 mL of 3% H2O2 to each of the four test
7. Using a clean dropper pipette, add 1 drop of enzyme suspension
to the test tube labeled 1 Drop. Note: Be sure not to let
the enzyme fall against the side of the test tube.
8. Insert the 1-hole stopper assembly into the test tube. Note:
Firmly twist the stopper for an airtight fit.
9. Shake or flick the tube to thoroughly mix its contents. The
reaction should begin. The next two steps should be completed
as rapidly as possible.
10. Close the air valve on the pressure sensor. Align the blue
handle with the side stem.
11. Start measuring the pressure by clicking on the Start button.
12. If you do not manually stop the program, data collection will
end after 3 minutes. If the pressure exceeds 1.3 atmospheres,
the pressure inside the tube will be too great and the rubber
stopper is likely to pop off. If the pressure exceeds 1.3 atmospheres:
- Stop the data collection by clicking on the Stop button.
- Open the air valve on the pressure sensor.
13. After the computer stops, save your data as directed by your
14. Find the rate of enzyme activity.
15. Add 2 drops of the enzyme solution to Test Tube 2. Repeat
16. Add 3 drops of the enzyme solution to Test Tube 3. Repeat
17. Add 4 drops of the enzyme solution to Test Tube 4. Repeat