Background Information:
Enzymes are mainly forms of protein produced by living cells. The three dimensional shape of an enzyme is vital to their catalytic activity. An enzyme works as a catalyst to speed up chemical reactions. They are selective in what they bind to and specific to their substrate. An enzyme’s shape is a huge factor in determining how it will react and what substrate the enzyme will react with. Enzymes have an active site where it bond with substrates at the and reacts with the substrates to produce and release a product. The allosteric sites are what affects an enzyme’s shape.
Enzyme activity can be affected by a variety of factors, including, temperature or pH changes. High temperatures and pH have the ability to denature enzymes. When an enzyme is denatured, this inhibits their ability to perform or eliminates it totally. However, if there is an increase of enzymes in a solution, it is possible that the enzymes can overcome inhibitors. The inhibitors that the enzymes face are noncompetitive and competitive inhibition. Noncompetitive inhibition decreases the enzymes activity, whereas competitive inhibition prevents the binding of the enzyme to the right substrate.
An enzyme made up of four polypeptide chains, and found in most living organisms is known as a catalase.The main function of the catalase is to prevent hydrogen peroxide from becoming a toxin. In the metabolic process, hydrogen peroxide is a by product, and it can be very dangerous in large doses.
The formula for the reaction that occurs between the catalase and hydrogen peroxide, shows that two hydrogen peroxide molecules undergo decomposition through the catalase and then form water and oxygen gas. The formula is as follows:
Enzyme activity can be affected by a variety of factors, including, temperature or pH changes. High temperatures and pH have the ability to denature enzymes. When an enzyme is denatured, this inhibits their ability to perform or eliminates it totally. However, if there is an increase of enzymes in a solution, it is possible that the enzymes can overcome inhibitors. The inhibitors that the enzymes face are noncompetitive and competitive inhibition. Noncompetitive inhibition decreases the enzymes activity, whereas competitive inhibition prevents the binding of the enzyme to the right substrate.
An enzyme made up of four polypeptide chains, and found in most living organisms is known as a catalase.The main function of the catalase is to prevent hydrogen peroxide from becoming a toxin. In the metabolic process, hydrogen peroxide is a by product, and it can be very dangerous in large doses.
The formula for the reaction that occurs between the catalase and hydrogen peroxide, shows that two hydrogen peroxide molecules undergo decomposition through the catalase and then form water and oxygen gas. The formula is as follows:
2H202 -----> 2H20 + O2 (gas)
During the pre-lab, my group noticed that the hydrogen peroxide became bubbly when green beans were added to the testing tube. My group filled up two test tubes with 10 mL of hydrogen peroxide, then placed a single green bean in one test tube, but two in the other. It was evident that the test tube with the two green beans reacted faster and had more bubbles. The hypothesis that we formed was that if we increased our amount of the catalase to the test tube filled with 10 mL of hydrogen peroxide, then the reaction would increase.
Lab Set Up
Procedure:
1. Fill a plastic container with water (room temperature) to about 3/4 of the way.
2. Submerge a 100 mL test tube into the plastic container and fill it up with water.
3. Keep the test tube upside down, with the opening end under the water, so it stays filled.
4. Suspend the test tube upside down in the clamp.
5. Adjust the test tube with the clamp so it suspends about 3 cm above the bottom of container.
6. Fill up a dropper with 10 mL of hydrogen peroxide and the catalase.
7. Place the dropper underneath the test tube in the plastic container, so that the opening of the dropper is at the opening of the test tube.
8. Record obseravations and data.
1. Fill a plastic container with water (room temperature) to about 3/4 of the way.
2. Submerge a 100 mL test tube into the plastic container and fill it up with water.
3. Keep the test tube upside down, with the opening end under the water, so it stays filled.
4. Suspend the test tube upside down in the clamp.
5. Adjust the test tube with the clamp so it suspends about 3 cm above the bottom of container.
6. Fill up a dropper with 10 mL of hydrogen peroxide and the catalase.
7. Place the dropper underneath the test tube in the plastic container, so that the opening of the dropper is at the opening of the test tube.
8. Record obseravations and data.
Hypothesis:
If the concentration of the catalase is increased, then it will increase the rate of the reaction.
The water level will decrease more quickly in Part B than in Part A.
If the concentration of the catalase is increased, then it will increase the rate of the reaction.
The water level will decrease more quickly in Part B than in Part A.
Data/Graphs:
Initial Rate
The initial reaction rate of an enzyme is the rate at which the reaction takes place initially. The calculated initial rates form the lab were the following:
A. 0.02 to 0.03 mL/sec
B. 0.02 to 0.03 mL/sec
B. 0.02 to 0.03 mL/sec
Though the rates were the same, the reactions differed in the time that it took the enzyme to react. Part A's reaction came to an end at about three or so minutes, whereas Part B continued for a five minute testing period.
Conclusion
An Enzyme's activity can be measured in many ways. In the lab, the amount of oxygen gas released by the reaction was measured. Although, the decreasing water level in the test tubes would have been another way that the enzyme activity could have been measured. The oxygen gas released from the dropper rose into the test tube and displaced the water in the tube. The oxygen gas that was realeased from the dropper served as a product of the reaction.
After about 4 minutes minutes, the average rate of reaction for Part A was a loss of 0.0225 mL of water per second. The average rate for Part B after about 4 minutes was a loss of 0.025 mL of water per second.
The hypothesis that when increasing the concentration of the catalase (catalyst), the rate of the reaction between the catalase and hydrogen peroxide would increase as well was correct. However, the experiment B was more reliable than A, because the efficency of the enzyme reaction was more noteciable. In a real world application, an increase in the concentration of an enzyme can allow reactions to overcome bological and physical inhibitors.
After about 4 minutes minutes, the average rate of reaction for Part A was a loss of 0.0225 mL of water per second. The average rate for Part B after about 4 minutes was a loss of 0.025 mL of water per second.
The hypothesis that when increasing the concentration of the catalase (catalyst), the rate of the reaction between the catalase and hydrogen peroxide would increase as well was correct. However, the experiment B was more reliable than A, because the efficency of the enzyme reaction was more noteciable. In a real world application, an increase in the concentration of an enzyme can allow reactions to overcome bological and physical inhibitors.
Sources of Error
There were several sources of error in the enzyme lab experiment. The lab began with with a major source of error, the test tube was not originally fitted in the correct position, and it was adjusted. This could have caused the reaction to have been altered because of the movement. The water levels were all accurate as the levels were hard to read, and after the timer went off for the intervals of seconds, the reader did not know the exact level until a little later.
Other sources of error included screwing on the lid of our catalase, hydrogen peroxide on too tightly. Because of the tight lid the reaction's results could have been altered. When the reaction began, it was also noted that not all of the hydrogen bubbles were following upward in the same direction. There were many bubbles escaping into the surrounding water and not filtering up to the test tube, as they should have. Also, a different group members did different jobs and frequently switched when one member was having trouble.
It is possible that the recorded data may be slightly off due to one group members perception of water level. These sources of error could have been avoided had the group established a more organized lab station and let one specific person do the readings of water levels instead of taking turns.
Other sources of error included screwing on the lid of our catalase, hydrogen peroxide on too tightly. Because of the tight lid the reaction's results could have been altered. When the reaction began, it was also noted that not all of the hydrogen bubbles were following upward in the same direction. There were many bubbles escaping into the surrounding water and not filtering up to the test tube, as they should have. Also, a different group members did different jobs and frequently switched when one member was having trouble.
It is possible that the recorded data may be slightly off due to one group members perception of water level. These sources of error could have been avoided had the group established a more organized lab station and let one specific person do the readings of water levels instead of taking turns.