Effects of Changes in Physical Properties on Enzyme Activity
Effects of Changes in Physical Properties on Enzyme Activity
By
Alex Hoffmann
First Individual Lab Report
Wednesday 7:30-10:15pm
10/24/12
Meghan Duell
Abstract
The goal of this lab was to determine the effects of certain physical properties on enzyme activity. Enzyme activity was measured by the height of the bubbles that appeared after the enzyme was added which are proportional to the rate of the reaction when time is constant. The fact that enzyme activity is affected by physical properties such as temperature, substrate concentration, and pH is clearly supported by my data, but the specific effects of these physical properties are not clear. My predictions varied from my results and can mostly only be explained by error.
Introduction
Enzymatic activity can be manipulated by changes in physical properties. Changes in heat, pH, and salt concentration can all have effects on the rate of enzyme activity (Farzin, 2012). Enzymes “catalyse the dismutation of hydrogen peroxide to oxygen and water (2H2O2 → 2H2O + O2)” which is the cause of the bubbles that can be observed and measured (Obinger, 2012). The output of oxygen occurs very rapidly when the reaction begins and bubbles appear quickly and clearly which serve as a very good form of measurement of enzyme activity (George, 1947). In a reaction in which an enzyme is involved, several steps occur. First, an enzyme-substrate complex is formed when the enzyme and substrate molecule bind together. The enzyme later releases the molecule as a product. This process can be viewed as an equation where E is the enzyme, S is the substrate, and P is the product: E + S → ES → E + P (Sadava et al., 2010). Changes in physical properties like those that were tested: temperature, substrate concentration, and pH will sometimes increase or decrease this occurrence.
Materials and Methods
In Experiment One I varied the temperatures of four separate samples of hydrogen peroxide in order to test the effects of
By
Alex Hoffmann
First Individual Lab Report
Wednesday 7:30-10:15pm
10/24/12
Meghan Duell
Abstract
The goal of this lab was to determine the effects of certain physical properties on enzyme activity. Enzyme activity was measured by the height of the bubbles that appeared after the enzyme was added which are proportional to the rate of the reaction when time is constant. The fact that enzyme activity is affected by physical properties such as temperature, substrate concentration, and pH is clearly supported by my data, but the specific effects of these physical properties are not clear. My predictions varied from my results and can mostly only be explained by error.
Introduction
Enzymatic activity can be manipulated by changes in physical properties. Changes in heat, pH, and salt concentration can all have effects on the rate of enzyme activity (Farzin, 2012). Enzymes “catalyse the dismutation of hydrogen peroxide to oxygen and water (2H2O2 → 2H2O + O2)” which is the cause of the bubbles that can be observed and measured (Obinger, 2012). The output of oxygen occurs very rapidly when the reaction begins and bubbles appear quickly and clearly which serve as a very good form of measurement of enzyme activity (George, 1947). In a reaction in which an enzyme is involved, several steps occur. First, an enzyme-substrate complex is formed when the enzyme and substrate molecule bind together. The enzyme later releases the molecule as a product. This process can be viewed as an equation where E is the enzyme, S is the substrate, and P is the product: E + S → ES → E + P (Sadava et al., 2010). Changes in physical properties like those that were tested: temperature, substrate concentration, and pH will sometimes increase or decrease this occurrence.
Materials and Methods
In Experiment One I varied the temperatures of four separate samples of hydrogen peroxide in order to test the effects of
References: Farzin. 2012. BIO181 Fall ‘12 Lab Manual. Arizona State University. Obinger C. 2012. Catalases and Hydrogen Peroxide Metabolism. Science Direct (**Edition**) [Internet]. [2012 Sept 15, cited 2012 Oct 21] 525(2):93-94. Available from: http://dx.doi.org.ezproxy1.lib.asu.edu/10.1016/j.abb.2012.07.005 Sadava D, Hillis DM, Heller HC, Berenbaum MR. 2010. What Are Enzymes? Life, the Science of Biology 9th edition. P. 156-158. George P. 1947. Reaction Between Catalase and Hydrogen Peroxide. Nature (**Edition**) [Internet]. [1947 Jul 12, cited 2012 Oct 21] 160:41-43. Available from: http://www.nature.com/nature/journal/v160/n4054/abs/160041a0.html