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Investigating the effect of temperature on the activity of protease enzyme.

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Investigating the effect of temperature on the activity of protease enzyme Introduction The protease enzyme breaks down milk, which is insoluble and cloudy into amino acids, which are soluble and clear. In this investigation I will examine the effect that the variable of temperature has on the activity of the protease enzyme. Prediction I predict that as the operating temperature of the enzyme increases, the enzymes activity will increase at quite a fast rate from 0�C to around 30�C, and then continue to rise, at a much slower rate, until around 60�C. The optimum temperature of the enzyme therefore will be approximately 60�C. I predict that after 60� the activity of the enzyme will fall sharply. The reason for my prediction is that up to around 60�C the activity of the enzyme should increase because the heat gives the enzyme more energy meaning it is more active, however after 60�C the heat causes the enzymes active site to denature meaning it will show very limited activity. Plan In this experiment the manipulated variable will be the temperature at which the reaction between the protease enzyme and milk takes place. ...read more.


To do the experiment our class was divided into 8 groups of 4 or 5 people, one group per temperature. We had a water bath set to the correct temperature for each of the tests. Each person took 5mls of 0.5% protease solution, and 5mls of 2% milk solution, measured with a syringe for accuracy, and heated them to their temperature in individual test tubes. The solutions were mixed together after 10 minutes, and allowed to react for a further 4 minutes, after 4 minutes the solution was transferred into a cuvette using a pipette. The cuvette is put into the colorimeter and the percentage of light transmission is measured and everyone noted down their results into a table for the entire class. We ensured that the experiment was a fair test by using a syringe to measure the amount of each solution we used, as for the result to be accurate the same amount of each solution should be used. We also carefully timed the 4 minutes that the solutions were allowed to react before we removed the protease and milk solution from the water bath and joined the queue for the colorimeter. ...read more.


I believe that this could have been the cause of some anomalous results, for example the unusual dip in activity at 44�C and 52�C could have been caused by too little time for the reaction to occur, or by mistakes in the amounts of protease or milk measured and used in the experiment. The other anomalous result was the control experiment for 38�C, in which water and milk solution had a 50% light transmission. I suspect that this experiment may have somehow become contaminated with the protease enzyme, which would have caused the unusually high reading. The experiment is very suitable for this investigation it provides accurate results as to the activity of the enzyme without manipulating it's results. The experiment would have produced more accurate results if a measurement of activity had been taken at intervals of 5�C, making the exact temperature at which the enzymes denature and the optimum temperature of the enzyme much clearer from the results. If we were to conduct this experiment again I would suggest that the different groups working on different temperatures should have been set off at 5 minute intervals which woud greatly reduce the waiting time to take the results of each experiment leading to greater accuracy throughout the results. ...read more.

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