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The Effects of pH on Amylase

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Kate Clifford

on 23 October 2014

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Transcript of The Effects of pH on Amylase

What are Enzymes?
If we add pH 4 or pH 10 buffers to a 5% amylase and a 2 percent starch solution, the buffers will denature the amylase and make it ineffective.
The pH 7 and 8 buffers will not denature it because of how neutral they are, so they will not make the amylase ineffective.
8 Test Tubes
2% Starch
4 pH's (4,7,8,10)
5% Amylase
Test tube rack
10 droppers
Stop watch
The expected results were the pH of 10 would change the solution of iodine and 2% starch into a clear/ cloudy solution first because it was the most basic meaning it would break down the starch faster.
The next one to change was expected to be pH's of 7 and 8 because they were more neutral but still less acidic than the pH of 4.
pH of 4 should have been the last one to change because it was the most acidic.
The more neutral a pH is, the less likely it is to denature the enzyme

The solutions weren't added in at the same time which could have affected the end result timings.
The dropper measurements weren't exact because the solution had to be added more than once to get the accurate results.
Next time, the pH should be done separately and recorded the exact amount of time for each solution.
Procedure & Materials
The Effects of pH on Amylase
Expected Results compared to Actual Results
Sources of Error
pH of 4 wasn't clear at the end of 10 minutes.
pH of 7 took about 10 minutes to turn clear.
pH of 8 took about 10 minutes to turn clear.
pH of 10 took about 7 minutes to turn clear.
pH 4
pH 7
pH 8
pH 10
We found that different enzymes have different optimal pH values. At the optimum pH, the rate of reaction goes much faster. If the pH is higher or lower than the optimal level, the rate of reaction will decrease and will solely denature the enzyme. Extreme changes in pH can cause the enzyme to lose it's function entirely and denature it. However, there are other factors such as temperature or heavy metal ions.
place 4 test tubes on side of the test tube holder & the other 4 on the other side
add 4ml of each pH into each of the 4 test tubes

add 4 ml of the 5% amylase solution into the same 4 test tubes of the pH's
Procedure Continued
let the first 4 test tubes sit at room temperature for 5 minutes.
while the first 4 test tubes siting, in the next 4 test tubes, add 4 ml of 2% starch
take pictures of all of the test tubes
after the 5 minutes, take the 4 test tubes with the iodine and starch and pour the solution into the test tubes with the amylase and pH's
Amylase in the Body
Amylase is an enzyme that catalyzes hydrolysis of starch into sugars. In the human body, amylase exists in saliva and in the pancreas of humans. In the pancreas it's best pH are around 6.7 and 7.0. In saliva, it does best between 4.6 and 5.2. Depending on the optimal pH, the pH factor could speed up the rate of reaction or denature and change the shape of the enzyme causing it to completely lose its function.
watch for 10 minutes how the solutions change and take pictures of the color variations
record results
In the experiment, there was a positive control and negative control.
The positive control included 2% starch, 5% amylase, and iodine and the negative included the 2% starch and iodine.
The negative was going to show what starch looks like when iodine comes in contact with it which made the solution turn black.
The positive would show how the reaction would play out normally which could take up to hours of waiting to see change, but with the added pH's, the reaction went faster showing the
Was the Hypothesis supported?

Our hypothesis stated that the neutral pH's would turn clear first because the extreme acidic or extreme basic would effect the enzyme negatively by denaturing it. We did not put into consideration the optimal pH of the amylase of the most acidic acid that would break down the starch into sugars. Our hypothesis was not supported due to the fact that the pH of 10 turned clear first and the neutral pH's of 7 and 8 turned last.
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