# Determining the Optimal Temperature and Ph of Barley Amylase Essay

Abstract

The purpose of this experiment was to find the optimal temperature and pH of barley alpha-amylase. I hypothesize that the optimal temperature would be 55 degrees Celsius and the optimal pH would be 5.5. In this experiment, the starch is used as a substrate to examine the optimum temperature and pH for the reaction of alpha amylase. It is known that the measuring of disappearance (absorbance) of the substrate starch with iodine using spectrophotometer will show the concentration of the substrate which will also reflect on the reaction rate. Once the reaction rates are figured out, the optimal temperature and pH can be determined. The result concluded that the

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For the pH experiment, six different starch solutions were prepared by mixing 35ml of stock starch solution with 35ml of water buffered at the pHs of 4.0, 4.5, 5.0, 5.5, 6.0 and 6.5. All these starch solutions are in the separate reaction flask. Then the basic procedure was followed.

After obtaining all the data, the reaction rate was found using the following formula: Reaction rate = (1/2 delta Absorbance)/ (Time that Ai -1/2delta Absorbance Took) (Vliet,2008)

Results

The results for the absorbance readings over time of reactions at different temperature turned out to be a negative slope, bowed-in graphs. Couple of the points from different temperatures overlapped but generally the graph showed consistence. From initial point to around 2-5 minutes, most of