Phosphatase Optimum Temperature

Title

The purpose of this experiment was to test the reaction rate of an enzyme in various temperatures to further learn what such enzyme’s (phosphatase) optimum temperature is. By learning what the optimum temperature is, we can hypothesize what type of environment the specimen in which the enzyme was isolated from lives in. In this experiment, therefore, the independent variable was the temperature in which the reactions took place. The dependent variable was the rate of the reactions measured by the light absorbance of the product (p-nitrophenol). The control treatments of the experiment were pH levels and substrate concentration. Each test tube was given 1mL of 5.33mM p-nitrophenol phosphate (the substrate) and 1mL of pH 4.5 citrate buffer. After an incubation of 5 minutes in their respective temperatures, 1mL of 0.03mg/mL phosphatase was added and the tubes were incubated again in their respective temperatures for 15 minutes. The substrate concentration was measured by light absorbance using a spectrophotometer at an absorbance of 410nm.

Results

Reaction rate in the highest tested temperature, 71oC, were much lower than that of its preceding temperature, 52oC. Otherwise, there was a steady increase in the reaction rate for phosphatase as temperature went up. The peak of reaction rate with the given temperatures was in fact 52oC. Figure 1.1 The effects of temperature on reaction rate. The reaction rate of the enzyme phosphatase as it performed in various temperatures, increasing approximately by 20oC, starting at 0o and ending at 71o. Each point represents the mean concentration of product (p-nitrophenol) in each variable divided by the reaction time of 15 minutes.