Enzyme Lab Report

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Enzyme Reaction to Variable
Elizabeth Alvidrez
University of Texas at El Paso

Abstract:
An enzyme is a protein that serves as a biological catalyst (Denniston, 2007). Metabolic reactions happen with in cells. Enzymes are proteins that are used to speed up these reactions without being consumed by them (Mader, 2010). Catalase is a catalyst that digests potent hydrogen peroxide and converts it into H2O and O (Campbell Reese, 2008). The environment plays an important role in the reaction that enzymes have. In this experiment, enzymes were exposed to changes in temperature, pH, and concentration.

Introduction
In this experiment, the environment of the enzyme was altered, by increasing or decreasing the temperature, pH and concentration. The purpose was to observe if and how the enzyme would react to such changes. This experiment tested whether heating or cooling a catalase would increase or decrease the rate of reaction. The temperature was increased by placing the test tube in boiling water to test if the enzyme would begin to denature and break down, causing less of a reaction. The temperature was also decreased by placing the test tube in a refrigerator to test if the enzyme would slow down and the reaction would be minimal or it would cease. Altering the pH would cause denaturing of the enzymes and slow its reaction rate to almost non-existent. Increasing the concentration of catalase, you will see a correlation in the increase of the reaction.

Material
• Potato
• 250mL Beaker
• Four 100mm test tubes
• Mortar and Pestle
• Refrigerator
• Hydrogen Peroxide
• 7.0 pH Phosphate buffer solution
• Thermometer
Methods
The potato was crushed with a mortar and pestle to make a slurry (the catalase) and poured it into a 250 ml beaker. Four 100 mm test tubes (marked at every cm) were filled from the beaker with a mixture of the catalase and a 7.0 pH phosphate buffer solution to the 1 cm mark on each of the test tubes. One test tube was placed in the refrigerator at 7°C, one in the incubator at 37°C, one in boiling water at 100°C, and one was left at room temp (23°C). After 15 minutes, remove the test tubes one at a time and 2 cm of hydrogen peroxide were added to each and then swirled for approximately fifteen seconds. Twenty seconds after swirling the height of the bubble column was measured and recorded.

For the second test, the concentration of the peroxide to catalase ratio was changed, leaving the temperature and amount of hydrogen peroxide as constants. Three test tubes (all marked at every cm) were used. In the first tube, 1cm of catalase mixture with 4cm of hydrogen peroxide was added. The second tube contained 2cm of catalase with 4cm of hydrogen peroxide was added and the third was added, 3cm of catalase with 4cm of hydrogen peroxide. The height of the bubble column was recorded for each.

For the third test, the pH of each solution was altered, keeping the concentration and temperature constant. Three separate test tubes (all marked at every cm) were filled, each starting with 1cm of catalase. 2cm of hydrochloric acid was added to one tube, with a pH of 3. Test tube two was left neutral adding 2cm of a 7.0 phosphate buffer, and to the third test tube was added 2cm of sodium hydroxide with a pH of 11. 4cm of hydrogen peroxide was added to all three tubes. They were swirled for approximately fifteen seconds. After that, the height of the bubble column was recorded.

Results
For our first test, the height of the bubble column was recorded as a reaction to the enzyme and temperature change. The following results were obtained. The test tube that was placed in the incubator (37°C) had 10mm of bubble height. The test tube that was left at room temperature (22°C) had a small reaction with 5 mm of bubble height. The test tube that was in the refrigerator (7°C) had the largest reaction with 15 mm of bubble height. The test tube that was...
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