|MadSci Network: Biochemistry|
To learn about the pH dependency of catalysis by an enzyme, or for that matter, any chemical reaction, one measures the rate of reaction at a series of pH values, and then plots the data on a graph with the rate on the y-axis, and the pH on the x-axis. This type of graph is called a pH- rate profile. The pH at which the reaction goes at the fastest rate is called the pH optimum. In your message you mention that you have collected some data, but you donít say what type of data, so Iím not sure if you have been able to measure rates and want to know how to analyze them, or if you are asking about how to measure the rate of reaction. To measure the rate of a reaction, one measures either the appearance of a product, or the disappearance of a reactant, over time. Such measurements can be made by using some method, called an assay, that is sensitive to the concentration of either the reactant or product that you want to monitor. This can be done spectroscopically (for example, by following the increase in the absorption of light at a particular wavelength), or by chemically analyzing the reaction mixture at periodic time intervals. Once you have measured the rate of your catalase reaction at several different pH values, you will be ready to produce your pH-rate profile. Here is a web site that discusses the effect of pH on enzymatic activity that may help you: http://www.worthington-biochem.com/introBiochem/effectspH.html
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