Enzyme lab

Part I

Claim

The question that we were answering in the second procedure of the lab was, how does PH affect enzymatic activity? My hypothesis was that a PH different than 7 would negatively affect the enzymatic ability of the peroxidase. I said this because the 1st  procedure used distilled water ( which has a PH of 7) and the solution of peroxidase hydrogen peroxide and guaiacol turned a brown indicative of significant enzyme activity. Each enzyme functions best at certain PH value and because of the aforementioned information I thought 7 was that value. To test the hypothesis my group filled 5 test tubes with 7ml of distilled water, .3ml of .1% hydrogen peroxide  and .2ml of guaiacol and 5 other test tubes with 6ml of a specific ph solution and 1.5ml of peroxidase. We then mixed the test tubes and then recorded the color changes every minute for 4 minutes. Our independent variable was the ph solution and the dependent variable was the color of the solution.

Evidence

Enzymatic ability of peroxidase at (Figure 1)

ph value	color at 0 min	color at 1 min	color at 2min	color at 3 min	color at 4 min
3	yellowish brown	yellowish brown	yellowish brown	yellowish brown	yellowish brown
5	light brown	orange brown	dark brown	dark brown	dark brown
7	clear	semi brown	light brown	light brown	light brown
8	semi brown	light brown	light brown	light brown	light brown
10	clear	clear	clear	clear	clear

For 5 various ph’s we recorded color changes for 4 minutes. In figure 1 the results are displayed.

Reasoning

With the evidence that was collected, I concluded that my hypothesis was wrong. The ph of 5 allowed for the solution to reach the darkest brown in the time frame we allowed. This would indicate that a ph of 5 is the ph at which peroxidase functions best. At ph 8 the enzyme performed similarly to ph 7.  At all other Ph’s beside 7,5,and 8 the effect on enzymatic activity was negative. This let’s me conclude my hypothesis was wrong because in two scenarios there was no negative effect on the enzyme's ability to aid the reaction despite differences in ph.

Part II

Claim

For the independent part of the lab where we came up with our own question, our question was: how does the rate of the reaction change with differing amounts of peroxidase? My hypothesis was that the greater the amount of the enzyme the greater rate of the reaction will be. To test this we used the exact same procedure as Part I except for these changes: we used 6ml of  distilled water instead of different ph solutions, we changed the amount of peroxidase for each beaker, and we only let the beaker sit until it turned as brown as the beaker in procedure 1.  The amount of .1% hydrogen peroxide, the guaiacol, and the amount of water in each beaker were all constants. The beaker with 0ml of peroxidase was the control. Our independent variable is the amount of peroxidase and the dependent variable is the rate of the reaction.

Evidence

Effect of differing amounts of peroxidase in hydrogen peroxide solution (figure 2)

amount of peroxidase in ml	time it took fully colorate (in minutes)
0	n/a
1.5	4:00
0.5	5:00
2.5	2:21
3.5	0:58

The data in figure 2 is of how long the solutions with differing amounts of peroxidase took to fully colorate.

The calculations below are how I got the rates in figure 3. I first got the amount of hydrogen peroxide in .3ml of .1% hydrogen peroxide then I got the amount of hydrogen peroxide the enzyme broke down per minute.

Reasoning

With the evidence collected, I concluded that the hypothesis was supported by the experiment. The data shows that the solution with the highest rate of reaction was the solution with 3.5 ml of peroxidase in it while the solution with the lowest amount of peroxidase did not react substantially. This happened because with more enzymes there were more active sites for the hydrogen peroxide to bind to at any given time. Therefore the reaction would be able to happen at a much faster rate than with a lower amount of enzymes.