The Effect of pH on the Digestion of Casein by Trypsin

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The Effect of pH on the Digestion of Casein by Trypsin When planning the experiment, the equipment and method had to be well thought-out in order for the experiment to be accurate and efficient. Firstly, I have chose to use a 1% trypsin concentration then altered it to 0.8%, because a higher concentration means more trypsin molecules in the solution and therefore more enzyme substrate complexes are likely to occur with the casein in the milk, causing digestion of the casein to be faster. However, I don’t wantowever digestion to occur too quickly as I will not be able to analyse the effect of PH. Therefore, I chose a lower concentration which would allow me to test the percentage transmission at different PH. Enzymes are proteins that act as catalysts to speed up reactions without being used up. However, I will use a higher amount of enzyme than substrate as although it is reusable, the reaction will proceed at its maximum rate and the enzyme will not be the limiting factor. The use of digital scales would provide more accuracy as you can obtain measurements of to up several decimal places. Skim-milk will be used rather than whole milk because skim-milk provides more protein and therefore more casein in the experiment. The effect of a change in PH on enzymes is the alteration in the ionic charge of amino acids at the active site, so the active site changes and the enzyme can no longer form enzyme-substrate complexes. To test the effect of various PH on the digestion of casein I decided to use PH 4, PH7 and PH9.5 because I could then, compare the effect of acidic neutral and alkaline conditions on the digestion catalysed by tr... ... middle of paper ... experimental time and may take different times for each, therefore shaking all the test-tubes will ensure that the reagents are mixed initially. I intended to use immobilized enzymes as they would be easy to remove in order to stop the reaction i.e. Alginate beads which can be sieved. However we know that immobilization may lead to loss of enzymatic activity e.g. due to the immobilizing framework hindering the arrival of substrates into the active site. Therefore, when removing the test-tubes from the water bath and placing solutions in the colorimeter, I will have to work quickly as immobilized enzymes won’t be used and the reaction will not be stopped. Finally repeating the experiment thirty times would allow better evaluation of the experiment and provide sufficient data to carry out statistical tests.

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