Enzyme Action
Computer
Enzyme Action: Testing Catalase Activity
6A
H2O2 is toxic to most living organisms. Many organisms are capable of enzymatically destroying the H2O2 before it can do much damage. H2O2 can be converted to oxygen and water, as follows: 2 H2O2 → 2 H2O + O2 Although this reaction occurs spontaneously, enzymes increase the rate considerably. At least two different enzymes are known to catalyze this reaction: catalase, found in animals and protists, and peroxidase, found in plants. A great deal can be learned about enzymes by studying the rates of enzyme-catalyzed reactions. The rate of a chemical reaction may be studied in a number of ways including: • measuring the rate of appearance of a product (in this case, O2, which is given off as a gas) • measuring the rate of disappearance of substrate (in this case, H2O2) • measuring the pressure of the product as it appears (in this case, O2). In this experiment, you will measure the rate of enzyme activity under various conditions, such as different enzyme concentrations, pH values, and temperatures. It is possible to measure the concentration of oxygen gas formed as H2O2 is destroyed using an O2 Gas Sensor. If a plot is made, it may appear similar to the graph shown. At the start of the reaction, there is no product, and the concentration is the same as the atmosphere. After a short time, oxygen accumulates at a rather constant rate. The slope of the curve at this initial time is constant and is called the initial rate. As the peroxide is destroyed, less of it is available to react and the O2 is produced at lower rates. When no more peroxide is left, O2 is no longer produced.
Ev
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Biology with Vernier
py
Many organisms can decompose hydrogen peroxide (H2O2) enzymatically. Enzymes are globular proteins, responsible for most of the chemical activities of living organisms. They act as catalysts, substances that speed up chemical reactions without being destroyed or altered
Enzyme Action: Testing Catalase Activity
6A
H2O2 is toxic to most living organisms. Many organisms are capable of enzymatically destroying the H2O2 before it can do much damage. H2O2 can be converted to oxygen and water, as follows: 2 H2O2 → 2 H2O + O2 Although this reaction occurs spontaneously, enzymes increase the rate considerably. At least two different enzymes are known to catalyze this reaction: catalase, found in animals and protists, and peroxidase, found in plants. A great deal can be learned about enzymes by studying the rates of enzyme-catalyzed reactions. The rate of a chemical reaction may be studied in a number of ways including: • measuring the rate of appearance of a product (in this case, O2, which is given off as a gas) • measuring the rate of disappearance of substrate (in this case, H2O2) • measuring the pressure of the product as it appears (in this case, O2). In this experiment, you will measure the rate of enzyme activity under various conditions, such as different enzyme concentrations, pH values, and temperatures. It is possible to measure the concentration of oxygen gas formed as H2O2 is destroyed using an O2 Gas Sensor. If a plot is made, it may appear similar to the graph shown. At the start of the reaction, there is no product, and the concentration is the same as the atmosphere. After a short time, oxygen accumulates at a rather constant rate. The slope of the curve at this initial time is constant and is called the initial rate. As the peroxide is destroyed, less of it is available to react and the O2 is produced at lower rates. When no more peroxide is left, O2 is no longer produced.
Ev
al
ua tio
n
co
Biology with Vernier
py
Many organisms can decompose hydrogen peroxide (H2O2) enzymatically. Enzymes are globular proteins, responsible for most of the chemical activities of living organisms. They act as catalysts, substances that speed up chemical reactions without being destroyed or altered