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Phosphorylase Lab Report

Decent Essays

Angie Phan
The Effects of pH and Temperature on Phosphorylase Assay
Introduction
An enzyme is a protein that acts as a catalyst which reduces the activation energy needed for a chemical reaction. Without the presence of enzyme, cell reactions would take so long that they would detectable. During a reaction, in the presence of an enzyme, the substrate first creates a complex with the enzyme. While the substrate is a part of the complex, it’s converted into the product. Then, finally, the complex dissociates from the molecule which allows the release of the enzyme and formed product. An enzyme’s activity depends on a variety of conditions which includes the pH level and temperatures. Phosphorylase is an enzyme that catalyze the addition of a …show more content…

For this experiment, we have to prepare our phosphorylase which extracted from a potato. We prepared by weighed about 250 grams of peeled potato and cut it into cubes. The extracts then blended with 100mL of 0.1M NaF. After filtered the contents into a clean 250mL centrifuge bottle, we centrifuged it for 3 minutes. Then, separated the supernatant into a centrifuge bottle, which is our phosphorylase preparation. The enzyme assay used in this experiment today is the iodine test. As the iodine reacts with starch, it will form a brown, blue or black precipitate due to the iodine ions forcing into a linear arrangement. The endpoint of the enzyme reaction indicates the presence of starch by using the iodine test to determine. The faster the endpoint is reached, the less active the phosphorylase is.

Discussion
Based on the class data of the pH of phosphorylase reaction, the potato phosphorylase is reached the endpoint which the phosphorylase active at pH 6, it started active within 6 minutes. The optimal pH of phosphorylase is at pH 7 which active just within 4 minutes. At pH 6, it started to breaking down the starch primer +glucose-1-phosphase into starch + phosphate which reacted with the iodine test to formed the blue precipitate. At the optimal pH 7, it shows that it maximized its activity. Comparing the data of the pH of the potato phosphorylase reaction with the study published by Russell Pressey from Plant

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