This piece of coursework will look at what effect temperature has on the activity of Trypsin and which temperature Trypsin works best at.
It was predicted that the milk would turn transparent quickest at the 40 oC temperature level, as the enzyme in a Trypsin is found in human bodies. The normal human body temperature is around 37 oC so the activity of the enzyme would work best at this temperature.
Method
A total mixture capacity of 10ml mixture Trypsin and milk, of 5ml of each, 5ml syringes were used to get the exact amount each time.
The temperature range of 60 oC to use for the experiment, between 10 oC and 70 oC using 10 oC increments.
A water bath was used to control the temperature of the mixture. Hot water from a kettle was used to heat up the Trypsin and milk mix, and ice was added to the water bath to cool it down when necessary.
Trypsin was added to the milk and see how long it took for the milk to become transparent. A piece of paper was placed behind the test tube with writing on it. When the writing was clearly readable, the elapsed time on the stopwatch was recorded.
The temperature of the water bath was controlled by adding ice or hot water to it. Separate test tubes were used for the Trypsin and milk in the water bath, these were left for 1 minute so that the contents would reach the same temperature as the bath.
Preliminary testing took place to establish that the experiment would perform as expected, with modifications to the method if required.
This is the results of the preliminary test.
Temperature
Times in seconds
10 oC
421
20 oC
133
30 oC
102
40 oC
82
50 oC
143
60 oC
159
70 oC
181
During the preliminary testing it was noticed that the temperature of the separate test tubes of liquids did not always reach the required temperature within 1 minute. It was decided to increase the time allowance to 2 minutes for the separate test tubes of Trypsin and milk get to the correct temperature before the were mixed together.
The equipment used for the experiment
Equipment
Number
Test Tube
45
Test Tube rack
1
5ml syringe
2
100ml beaker
1
Water bath (Ice cream container)
1
Trypsin
N/A
Powered milk
N/A
Stop watch
1
Kettle (hot water)
N/A
Ice
N/A
Thermometer
3
Powered milk was used so that the amount of calcium in the milk would be controlled and be the same for each experiment. Normal milk has variable calcium levels and would not produce a fair test.
Diagram of the experiment.
The left test tube always had Trypsin in it and the right always had the milk in it.
After a 2 minute period the Trypsin and milk were at the correct temperature then we added them together as shown in the diagram below.
Data
Data was collected from the experiment 3 times at each of the 7 different temperatures. The collected data is displayed in the table below.
times in seconds
Temperature
attempt 1
attempt 2
attempt 3
average
10 oC
378
458
480
439
20 oC
133
129
117
126
30 oC
118
98
102
106
40 oC
69
81
87
79
50 oC
103
171
155
143
60 oC
164
158
140
154
70 oC
173
147
212
187
Analysis
The collected data is presented as a graph, showing the average time the mixture took to change to transparent against temperature over the 60 oC range. Each temperature was repeated three times so that an average time could be established, this would also show up gross errors in the experiment.
A line of best fit was used on the graph.
Conclusion
The graph clearly shows that for this experiment Trypsin’s activity rate is quickest just below the 40oC temperature. We know this because the mixture of milk and Trypsin went transparent quickest at 40oC.
