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pH and Its Affect on Enzymes

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pH and Its Affect on Enzymes Introduction The Balancing Act: pH and Its Affect on Enzymes Enzymes are present in all living things. These specialized proteins speed up chemical reactions fast enough to sustain life (Johnson and Losos, 53). Since enzymes are a huge topic to even begin to cover, we tested a hypothesis using the enzyme "catalase" from a cow's liver as the basis of our enzyme research. This research project tested the hypothesis that extreme levels of pH will affect or denature the catalase. Before we can test the effects of "lower" or "higher" pH levels, we must first determine what constitutes these values. In the book "The Living World" by George Johnson and Jonathan Losos, pH levels are determined by a ruler of numbers, from 0 being the most acidic (Hydrochloric acid) to 14 being the most basic (Sodium hydroxide). The level of Hydrogen ions present characterizes these numbers. The average human has a pH level of approximately 7, which is neutral on the pH scale. So the higher and lower values will be set from the median of 7. Catalase is an organic catalyst, which is by definition a "Substance that increases the rate of a reaction without itself being altered". ...read more.


in each. The purpose of this is to test the affect of different pH levels on enzyme activity, so I next added the control, water, and the pH solutions of 2, 8 and 14 each separately to the test tubes with the shredded cow liver. Finally, I added the Hydrogen Peroxide (H2O2) and recorded the results after fifteen minutes. 3-23-10 Results Mixed Up, Time to Confirm or Make Null my Hypothesis After adding Hydrogen Peroxide to the liver/pH solutions, the level of foam put off by the catalase converting the H2O2 into carbon dioxide and oxygen was instantly telling of whether the pH levels had any effect on enzyme activity. The first result from the control (water) came in at 130 millimeters (mm), water has a pH level of 7, making it neutral- a very weak base and a very weak acid. The second result came from a solution of pH 2, which is very acidic. As illustrated in Figure 1, this acidic of a solution would appear to have nearly completely denatured the catalase. The results of the water solution increased my confidence in the possibility of better success with the next solution, a pH level of 8. ...read more.


The readings would be far more accurate if the mixtures were done multiple times for each reading, then you would be able to assess an average. The results from this experiment spark a very large hypothesis; that extreme levels of pH affect all enzymes. If this is true, then the level of pH in humans will directly affect their chemical reaction processes. But this leads one to think there must be a way our bodies regulate all this. And there is, cells control enzymes. "Many enzymes have shapes that can be altered by the binding of "signal" molecules to their sufaces." Such enzymes are called "allosteric". Enzymes are also usually regulated by a process called "feedback inhibition", in this case the product of the reaction acts as the repressor. To further test this hypothesis, one could test actual human liver and see if it functions best at its native pH level, if this also holds true, the results could be the basis for further research into enzyme function and activity in humans and animals Literature Cited Johnson, George, and Jonathan Losos. The Living World. 6th ed. New York, NY: McGraw-Hill, 2010. Print. Boise State University, and Judy Lonsdale. "Enzyme Function and Activity." Concepts of Biology Laboratory Manual. 5th ed. Dubuque, IA: Kendall Hunt, 2009. Print. ...read more.

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