An enzyme is a protein molecule that helps other organic molecules start chemical reactions with one another; however, the enzyme itself is not affected by the reaction. A substrate is the substance acted upon by the enzyme. In this lab, catalase is the enzyme and hydrogen peroxide is the substrate. Catalase is found in both plant and animal tissues, and is abundant in plant storage organs. In this experiment, catalase is used from potatoes. Catalase is important to living things because it prevents the accumulation of hydrogen peroxide in the cell. Hydrogen peroxide is produced naturally as a byproduct of metabolism.
It tends to disrupt the cells’ chemistry, too much can kill a cell. Therefore, the presence of catalase is needed to survive. Catalase breaks down the toxic hydrogen peroxide into harmless water and oxygen. If the concentration of the substrate hydrogen peroxide is related to the reaction rate of the enzyme catalase, then an increase in the concentration of hydrogen peroxide will increase the reaction rate of catalase. Catalase: Methods and Materials In order to experiment and determine the affects concentration has on reaction rate, you will need several materials.
Such as, potato extract, crushed ice and water in a large beaker to keep the catalase cool, since catalase is sensitive to temperature. Hydrogen peroxide solution is needed at six different concentrations (10%, 25%, 40%, 60%, 75%, and 100%). Also, 0% hydrogen peroxide is needed, which is just simply water. In addition, you will need a 10 ml graduated cylinder, a 50 ml beaker, forceps, paper dots (Whatman #1 filter paper, 1 cm diameter), a paper towel, a stopwatch, and graph paper. During this lab, be careful of the hydrogen peroxide because it can damage skin and clothes.
Be sure to immediately rinse and spills with water. Throughout the lab, always keep the potato extract in the ice-water bath; catalase is very sensitive to warm temperatures. For starters, 0% hydrogen peroxide was tested as the control group; 10 ml of hydrogen peroxide was measured of using a graduated cylinder. This sample is then poured into a 50 ml beaker. After swirling the potato extract, using forceps a paper dot is picked up and immersed into the potato juice for five seconds. Then the dot is drained on a paper towel for 10 seconds.
Using the forceps the dot is picked up and placed in the bottom of the beaker containing the hydrogen peroxide solution. Soon the dot was expected to rise to the surface because the potato juice’s catalase would break down the hydrogen peroxide into water and oxygen. The oxygen gas gets trapped in the pores of the paper and caused to float. A stopwatch was used to measure the time in seconds from when the dot touched the solution until it reached the surface. The data was then recorded. The class was split into groups and each group was assigned a different percentile of hydrogen peroxide solution.