For the temperature portion of the investigation (conducted first), eight test tubes were placed in four temperature controlled water baths ranging from water and crushed ice (2( C) to near boiling (98(). The other baths were kept at room temperature (23( C) and an intermediary between this and boiling (75( C). Test tubes were left in the baths for ten minutes, until their temperatures at equalized. Starting with the coldest bath, the amylase mixture was poured into the starch solution and briefly stirred. Leaving the test tube in the bath, a single drop was removed every ten seconds using a plastic pipette and placed into a well containing the iodine solution. When the color remained orange, the reaction had been completed, and the time (i.e. length of reaction) was noted. This same process was repeated with the other three sets of test tubes at the other temperatures, washing and replacing the iodine trays when needed. To test for pH efficiency, different concentrations of the buffer solution were created at pH 3,5, 7, and 9. These were added one at a time to four separate test tubes of starch solution, and then the amylase solution was introduced. Again, drops of the combined solutions were transferred to wells on the iodine tray, and when the iodine solution remained orange the reaction was considered complete and the time noted.

Results

The results of the temperature portion of the experiment appeared fairly straightforward. At near freezing temperatures, the reaction took nearly eight minutes to complete. This time was cut in half at room temperature, and was diminished significantly again at 75( C. At 98( C, (near boiling), however, the reaction never took place. After ten minutes without change in the iodine solution, it was assumed that the amylase had been effectively destroyed by the high temperature and that no reaction was taking place.

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Temperature

In the pH experiment, the results were lightly more complex; rather than a simple increase in the efficiency of the reaction, a noticeable dip in the reaction time occurred in the neutral pH sample (pH 7), with effectiveness...

Extreme cold was not as inhibitive as I had thought, but it did slow the process significantly. It is possible that truly freezing temperatures would have stopped the reaction altogether. In general, until the boiling point is reached, the higher the temperature is the faster the reaction will take place. My hypothesis concerning the pH was off; the reaction was more efficient at the neutral pH, suggesting that the amylase actually prefers working in human conditions. My final hypothesis was somewhat inconclusive; there was a greater range of times in temperature, but small variations in pH had a bigger influence on the reaction than I had thought. This leads me to question why the acidity would have such an effect on enzyme reactions. It must have to do with the level of hydrogen atoms present, and the way they either facilitate or inhibit such reactions, but I would like to know the mechanism.