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Digestive Enzymes Breakdown Various Macromolecules

Satisfactory Essays
Background & Objectives: Digestive enzymes are present throughout the digestive system and are used to breakdown various macromolecules obtained from food. An enzymes activity is dependent upon the temperature and pH at which it is present. Enzymes work optimally at specific temperature and pH levels. The purpose of this lab is to examine various enzymes to determine which substrates they digest, and at which pH they work optimally.
Methods: The enzymes amylase, pepsin, and trypsin were each mixed with the substrates starch and albumin at pH levels of 2, 7, and 9. At 10 min intervals, the starch mixtures were treated with lugol’s solution and the albumin mixtures with biuret and ninhydrin solutions to determine whether digestion occurred. An unknown enzyme was then added to starch and albumin at the various pH and the same tests were performed to determine the identity of the unknown enzyme.
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Amylase at pH 2 showed presence of starch, whereas at pH levels 7 and 9 revealed absence of starch. The biuret test indicated undigested protein for all enzymes – except for the pepsin solution at pH 2 at 30 minutes contained short polypeptides. The ninhydrin test with amylase at pH 2 showed absence of amino acids, and their presence at pH 7 and 9. For pepsin, tests showed presence of amino acids, conversely trypsin had no amino acids present. The unknown exhibited similar results to trypsin – with the exception of the ninhydrin
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