The objective of this experiment was to determine if changes in pH or temperature affected the activity of enzymes, specifically the enzyme sucrase. Enzymes are protein molecules that act as biological catalysts to increase the speed of the reaction or to lower the activation energy of that reaction. However, the activity of an enzyme can be affected by physical factors such as pH and temperature because these factors alter the structure of the enzyme (Freeman, 2011).
We hypothesized that the enzyme would denature if it was exposed to a highly acidic or highly basic solution.Methods We obtained and labeled four test tubes to start our experiment, then, using a pipet, added 3 ml of water to test tube 1, and 3 ml of sucrase stock solution to test tubes 2, 3, and 4. We left test tubes 1 and 2 untreated, while we treated test tube 3 with 10 drops of concentrated HCl (hydrochloric acid) and test tube 4 with 10 drops of concentrated NH4OH (ammonium hydroxide). We then added with a pipet 2 ml of a 1% sucrase solution to each of the four test tubes. We mixed the contents of the test tubes by swirling them and allowed them to stand for ten minutes.
We then added 5 ml of Benedict’s solution using a pipetman to test the tubes for the presence of glucose and fructose, mixed the contents of each of the tubes, and heated them in a boiling water bath for two minutes.After we heated the test tubes, the colors in tubes 2, 3, and 4 changed. Test tube 2 turned orange, test tube 3 turned green, and test tube 4 turned blue. These results can be found in Table 1. Table 1: This table shows the color formed after the Benedict’s reagent was added and the solution was heated and tells what each of the colors meant.
In the first test tube, nothing happened because there was no enzyme stock solution added. The color was clear and there was no glucose or fructose because none was added to begin with. In the second test tube, the precipitate was orange. There was the most glucose and fructose in this test tube (3+) because it did not receive a change in pH, therefore the enzyme was not denatured and worked well. Test tube three showed less glucose and fructose than test tube two.
The precipitate turned green, which depicted a 1+ on the scale.Test tube four had the least amount of glucose and fructose. The precipitate turned blue, which was a sign of 0 glucose and fructose. We concluded that the presence of the acid and base in test tubes 3 and 4 was the reason for the lower levels of glucose and fructose. The change in pH altered the structure of the enzyme, causing it to denature.
Our conclusion agreed with our hypothesis, that a highly acidic of highly basic solution would denature the enzyme and cause it not to work as well. We did not encounter any obstacles or problems with our experiments. However, to produce more accurate results, we could have timed our experiment more precisely.
