Enzymes are proteins that enter a biochemical reaction and velocity up the reaction rate. Enzymes really help the reaction by take downing its activation energy. Like other proteins, they work decently because of their active site and a conformational alteration. The molecule that attaches to the active site is called the substrate. Cells and systems prosper due to enzymes increasing reaction rates. The rate of reaction due to the enzyme will invariably increase a important sum every bit long as there is a changeless copiousness of the substrate. Once this concentration starts to take down, the enzyme will interact with less as clip continues, hence the reaction rate will decrease.1
Many factors can impact the enzyme ‘s ability to attach with the substrate and expeditiously assist the biochemical reaction. Competitive inhibitors attach to the active site to halt the bond of the substrate. Noncompetitive inhibitors attach at another subdivision so that there is a conformational alteration and the active site alterations shape. Besides molecules that really attach to the enzyme, the environmental conditions affect its efficiency every bit good. There is a premier scope of salt concentration, pH degree, and temperature when the enzyme prospers, but excessively high or excessively low will take to the denatured protein. When the enzyme denatures, it comes apart so that it can no longer map. 2
A self-generated reaction is one that has negative free energy ( G ) . These reactions can happen without outside energy come ining the system. The energy produced in the procedure is reused for the reactions. Bing a self-generated reaction does non intend that it is a speedy reaction, therefore the reaction can really happen really easy. This is where enzymes assist because they lower the activation energy and can greatly rush up the reaction. 3
The decomposition of H2O2 ( hydrogen peroxide ) into H2O and O2 is a self-generated reaction that needs an enzyme to rush up the reaction to go efficient. The chemical equation is:
2 H2O2 i? 2 H2O + O2
The enzyme that catalyzes the decomposition is Catalase.2 With this enzyme, the decomposition rate will increase.
Sulfuric acid, H2SO4, is an acid. When acids are added to a solution, the pH degree lessenings ( becomes more acidic ) . As explained above, enzymes have a specific pH degree they expeditiously work at, and if it varies from this degree, so the protein will denature. When the sulphuric acid is added to the solution, it acts as an inhibitor as the catalase denatures and the decomposition of H2O2 slows down to its normal rate. 2
Potassium permanganate, KMnO4, reacts with H peroxide and sulphuric acid to do other merchandises. After all H2O2 is used in the reaction, so the KMnO4 will non be consumed, therefore it will merely remain in the solution. Since the KMnO4 has a purple colour, the solution will remain a purple brown when this happens. The measuring of KMnO4 is relative to the H2O2, hence, if the sum of KMnO4 consumed before the solution alterations colourss is measured. This shows how much H2O2 is left in the solution, which can be compared with the initial sum to happen how much was consumed. The existent chemical equation is:
5 H2O2 + 2 KMnO4 + 3 H2SO4 i? K2SO4 + 2 MnSO4 + 8H2O + 5 O2
The K permanganate reacts with both the H peroxide and sulphuric acid, hence all the reactants in the solution will be used when the KMnO4 is added. The merchandises include H2O and O, which are besides the merchandises when H2O2 decomposes. 2
The intent of the experiment is to compare the rate of reaction of H2O2 break uping with and without the presence of catalase to detect the importance of the enzyme for the reaction. The rate of reaction without the enzyme after yearss is besides tested. The consequence of the enzyme catalase on the rate of reaction over a few clip intervals is tested to see if the rate decreases or additions.
It was hypothesized that the rate of reaction of the non-catalyzed reaction would be really slow ; hence, there would be a batch of H2O2 left compared to the reactions with the catalase. It was hypothesized that if the H2O2 was left in a closed off environment for a long period, as in a few yearss, the reaction rate would non increase and there would be barely any H2O2 gone. As clip progressed during a reaction with catalase, H2O2 would go on to respond, but the reaction rate would slowly lessening, so less and less H2O2 would be used in the ulterior clip intervals.
Materials and Methods
Experiment One
1.5 % H2O2
2 Beakers/Containers
Water
H2SO2 ( 1 M Solution )
White Paper
2 Pipets
KMnO4
10 milliliter of 15 % H2O2 was placed in a beaker, and 1 milliliter of H2O was added. Then 10 milliliter of H2SO4 was added and the solution was assorted good. 5mL of the new solution was taken and placed in another little beaker and placed on a sheet of white paper to be able to see the alteration of colour of the solution. Next, a pipette was filled with KMnO4 and this was added to the beaker one bead at a clip while the solution was being assorted. Drops were added until the mixture turned a light purple chocolate-brown colour. The sum of KMnO4 used was noted. The solution was discarded in the sink and the containers were cleaned.
Experiment Two
1.5 % H2O2
2 Beakers/Containers
Water
H2SO2 ( 1 M Solution )
White Paper
Panpipes
Pipets to reassign solutions
KMnO4
15mL of the H2O2 solution was placed in a glass and sat uncovered at room temperature for about 72 hours. After that clip, 1 milliliter of H2O was added, so 10mL of H2SO4 was added and the solution was assorted. 5 milliliter of the solution was taken and placed in another beaker. A pipette was filled with KMnO4 and was added to the solution one bead at a clip as it was being stirred. Drops were added until the solution turned to a purple brown. The sum of KMnO4 used in the pipette was noted.
Experiment Three
1.5 % H2O2 solution
Beakers/Containers
Catalase
H2SO2 ( 1 M Solution )
White Paper
Panpipes
KMnO4
The Base Line was found from experiment one since both experiments were done at the same clip and under the same conditions, therefore the H2O2 was the same solution concentration from that experiment to this 1. Next, 10mL of H2O2 was added to a container and one milliliter of catalase was added to it. The mixture was stirred for the certain sum of clip, 10 seconds, so 10 milliliter of H2SO4 was added. 5mL of the new solution was taken out and set in a new container. KMnO4 was put in a syringe and a bead at a clip was added to the solution until it turned a purple brown. As each bead was added, the mixture was stirred. Then another 10mL of H2O2 went through the same procedure, except that 30 seconds occurred until the H2SO4 was added to the mixture. This same procedure occurred for 60, 90, 120, 180, and 360 seconds every bit good. Each clip, the base line, initial reading of the KMnO4 syringe, and the concluding reading of the syringe was written down. In the terminal, all the solutions were discarded in the sink and the containers and panpipes were cleaned.
Consequences
Table 1
Experiment One and Three: Base Line ( Reaction with H2O )
Sum of KMnO4 used in Pipette
5mL
Table 2
Experiment Two: KMnO4 Used
Sum of KMnO4 used in Pipette
5mL
Table 3
Experiment Three: Sum of KMnO4 in Syringe
10 sec
30 sec
60 sec
90 sec
120 sec
180 sec
360 sec
Base Line ( milliliter )
5
5
5
5
5
5
5
Concluding Reading ( milliliter )
3.5
3.1
3.4
2.9
4.3
5.4
4.5
Initial Reading ( milliliter )
6
5.1
5
5
5.4
6
5
Discussion
Table 4
Experiment Three: KMnO4 and H2O2 Consumed over Time
10 sec
30 sec
60 sec
90 sec
120 sec
180 sec
360 sec
Base Line ( milliliter )
5
5
5
5
5
5
5
Concluding Reading ( milliliter )
3.5
3.1
3.4
2.9
4.3
5.4
4.5
Initial Reading ( milliliter )
6
5.1
5
5
5.4
6
5
Amount KMnO4 Consumed ( milliliter )
2.5
2
1.6
2.1
1.1
.6
.5
Amount H2O2 Consumed ( milliliter )
2.5
3
3.4
2.9
3.9
4.4
4.5
Figure 1
It was hypothesized that without catalase, the decomposition of H2O2 would travel really slow. During experiment one, this was tested to see how different the rate of reaction with and without the catalase is. In this experiment, H2O was added to the solution in topographic point of the catalase. As shown in Table 1, 5mL of KMnO4 was consumed before the solution turned a light brown. Since the KMnO4 reacts with H2O2, the colour of the solution does non alter until there is no more hydrogen peroxide to respond with. Therefore, it was concluded that there was 5mL of H2O2 left in the solution after decomposition occurred. Since there was a batch of H2O2 left in the titration when tested, it was concluded that the reaction rate without the enzyme is really slow. This is the basal line to compare to reactions including catalase so that the difference that the enzyme makes on the reaction rate can be seen.
It was hypothesized that over a few yearss, in unchanged conditions, H2O2 would non break up a important sum. In experiment two, this was tested. In ideal conditions and if the H2O2 was covered, so the concentration would remain similar to the original 1.5 % solution. The consequences show that 5mL of KMnO4 was used in the reaction with H2O2, hence 5mL of H2O2 was present in the solution. H2O2 was non perceptibly consumed during the 72 hours because the base line from experiment one had the same sum of H2O2 left as the titration in this experiment, as shown in Table 1 and 2. Therefore, it was concluded that the decomposition rate of H2O2 without catalase is about so slow for a significantly long clip that the reaction barely occurs. The reaction is still a self-generated reaction, but the rate is really slow. This shows how of import the enzyme is in the reaction for systems such as the human organic structure. Without the enzyme, the decomposition of H2O2 would barely go on and the concentration of the H peroxide would increase.
In experiment three, it was hypothesized that the H2O2 would go on to respond at each clip interval, but that the reaction rate would diminish after a certain point. As shown in Table 4, the KMnO4 consumed during each clip interval decreased. Since it is a direct proportion of the H2O2 left in the solution, it was concluded that the H2O2 was continually consumed during the clip intervals. Therefore, the hypothesis was right. There was a important addition of H2O2 consumed from the base line in the short clip period when the catalase was added. This is important because it shows how of import the catalase is for the reaction to happen at an increased rate. The rate of reaction finally slowed overall at the 180-second interval. Get downing here, the reaction rate slowed overall. As shown in Figure 1, the incline of the line increases between 10 and 60 seconds and 90 and 180 seconds at a steeper angle than 180 to 360 seconds. Therefore, it was concluded that the rate of reaction finally slowed even with the enzyme. This is due to the concentration of substrate in the solution. In the beginning of the reaction, the rate was high, and by the terminal of the clip, the reaction started to decelerate. It was concluded that as the longer the reaction occurred, the slower the reaction would take topographic point.
