Enzyme Catalysis
An Investigation in Enzymes
Abstract:
Introduction:
A catalyst is a substance that speeds upa chemical reaction. Most catalysts found in cells are enzymes, specialized proteins that react with specific reactants, or substrates. Enzymes are specific to a substrate because of their shape.1 Environmental factors, such as changes in temperature and pH, can affect the shape of the enzyme, and thus decrease its specificity to a substrate.1 Variations in the concentration of enzyme or the concentration of the substrate can also cause the activity rate to change. Enzymes work in specific environmental conditions.3 For example, the enzyme present in the acidic environment of the stomach will not work as well in the mouth, which is more neutral.
Catalase is a specific enzyme found in all living things that acts as a catalyst to help break down peroxide. Peroxide, H2O2, is a waste product of cell functions and can be harmful to cells if it is not broken down immediately. Catalase breaks peroxide down into water and oxygen, which are harmless to cells and can easily diffuse out through the cell membrane.2 The rate of this reaction may change depending on the amount of enzyme or substrate present when the reaction is taking place or if environmental factors have caused a change in the shape of the enzyme. An accumulation of waste products in the body can result in changes in these environmental factors. A build-up of carbon dioxide can cause the blood to become more acidic or toxins may cause a fever.3
Materials and Methods
The solution containing the enzyme catalase was prepared using a package of active yeast and water. This solution was used to saturate small paper disk in order to test the enzyme activity of the catalase enzyme produced by the yeast cells. Three catalase solutions were used for this experiment: normal catalase, catalase that had been heated, and catalase that had been exposed to acidic conditions (low pH).
To test the enzyme activity, paper disks were saturated with one of the catalase solutions and dropped into a beaker containing hydrogen peroxide. As the peroxide was broken down by the catalase enzyme, the accumulation of oxygen bubbles on the disk caused it to rise to the top of the beaker. The time it took for the disk to rise to the top of the peroxide was measured and recorded in a data table. This process was repeated using 5 disks in each of the 3 catalase solutions.
Results (You will complete this section)
Discussion
Works Cited
- “Enzymes Make the World Go ‘Round.” Chem4Kids.com: Biochemistry: Enzymes.N.p., n.d. Web. 25 Feb. 2014.
- “Catalase.” Princeton University. N.p.,n.d. Web. 24 Feb. 2014.
- “Factors affecting Enzyme Activity.” A Level Notes. N.d.,n.d. Web. 26 Feb. 2014.