Enzyme Lab

Enzyme Lab Write-Up

Procedure 2: Determining the Effect of pH on Enzymatic Activity.

Question: How does  change in pH affect rate of enzymatic reaction?

Claim: As the concentration goes up, the enzymatic activity also goes up until it reaches its maximum of pH7 and decreases once again because there are not enough substrate molecules to interact with the enzyme.

Procedure:

1. 12 test tubes were prepared. 6 (substrate) tubes contained 7 mL of distilled water, .3 mL of hydrogen, and .2 mL of Guaiacol. The other 6 (enzyme) tubes contained 6 mL of specific pH solutions, and 1.5 mL of peroxidase.
2. A substrate and an enzyme were combined and as the reaction occurred we timed it from the beginning to the end (2 minutes).
3. We recorded the observed color for each tube every 20 seconds
4. A palette/ color chart was used to quantify the color changes observed.

Evidence:

Observed Color change of each test tube containing different pHs for 2 minutes

Color Change : represented in blue

pH	20 seconds	40 seconds	60 seconds	100 seconds	120 seconds	140 seconds
3	1	1	1	2	2	2
5	1	2	3	4	5	6
7	2	3	4.5	5.5	6	8
8	2	3	4	5	5.5	6
10	1	1	1	1	1	1

The chart above shows the color changes of the same substrate interacting with five different enzymes of varying pHs. The test tube which interacted with pH7 had the fastest color change of all 5 of the tubes. As the pH levels got further away from 7 they rates decreased to a point in which barely any color change was observed.

Reasoning:

As the number of enzymes decrease, the rate of reaction will decrease as well due there being less and less enzymes available to perform the reaction. This explains why any number greater than pH7 had a slowerd rate and less color changes. As the substrate level increases, so does the reaction rate due to there being more substrate for the enzyme present to work with. This explains why the rate increased and more color changes were observed as the pH increased to 7. A pH of 7 was probably the perfect mix of substrate and enzyme in which a reaction occurred effectively.

Procedure 3:

Question: In a time period of two minutes, what enzyme amount would reach the higher number of shade?

Claim: The tube which contains the most amount of pH buffer would reach the higher shade number because it contains the most pH.

Procedure:

1. 6 test tubes were prepared. 3 (substrate) tubes contained 7 mL of distilled water, .3 mL of hydrogen, and .2 mL of Guaiacol. The other 3 (enzyme) tubes contained varying amounts of ph7 buffer.
1. First enzyme: 6 mL of pH7 buffer, 1.5 mL of turnip peroxidase
2. Second enzyme: 4.5 mL of pH7 buffer, 3 mL of turnip peroxidase
3. Third enzyme: 6.75 mL of pH7 buffer
2. A substrate and an enzyme were combined and as the reaction occurred we timed it from the beginning to the end (2 minutes).
3. We recorded the observed color for each tube every 20 seconds
4. A palette/ color chart was used to quantify the color changes observed.

Evidence

Reasoning:

My hypothesis was correct, the tube containing the most amount of pH would reach the highest shade number since it has the most turnip peroxidase. This allowed for more interaction between the enzyme and the substrate and it increased the rate of reaction. The enzyme containing the 3 mL of ph7 reached 9 in two minutes while the other two only got to 7.