Report Essays - Chemistry, Catalysis, Peroxides, Hydrogen Peroxide

Enzymes: Catalase in the Liver and How it Reacts When Exposed to Hydrogen Peroxide Rainy M. Williams Jmeah Clark Saint Augustine's University Key Words Substrates Products Enzymes Catalase Hydrogen Peroxide Denaturalization Optimum Range Abstract All organisms rely on enzymes to catalyze a chemical reaction. An enzyme is a biological catalyst that increases the rate of a chemical reaction by lowering the level of activation energy that is necessary for the reaction to begin. Without enzymes, all chemical reactions necessary for life would proceed very slowly and would require more energy. If a substance (hydrogen peroxide) is added to an enzyme (catalase found in the liver), the reaction will speed up by bringing the reactants ( in this case, the substrates) within close proximity and facilitating their interaction when undergoing the reaction. The liver contains a specific enzyme called catalase.When hydrogen peroxide (H2O2) is added to the liver, the reaction is catalyzed due to the catalase, causing a chemical reaction to occur (essentially detoxifying the cells containing hydrogen peroxide), creating the products of water and oxygen. Introduction A substance that speeds up a reaction - without being a reactant - is called a catalyst. Catalysts used for biochemical reactions are known as enzymes, which are generally proteins. When enzymes are present in a reaction, the enzyme lowers the level of activation energy which is necessary for the reaction to begin. Enzymes work by binding reactant molecules and holding them in such a way that chemical bond-breaking and bond-forming can occur more readily. In order to catalyze a reaction, the enzyme will "grab" one or more reactant molecules to undergo the reaction. These reactants are called substrates, as they need the facilitation of an enzyme to complete the reaction. The part of the enzyme in which the substrates bind to the enzyme is the active site. The active site is the area in which the catabolic action occurs.The set of amino acids found in the active site as well as the 3D space give the enzyme its specific shape, size, and chemical behavior. An enzyme's active site is uniquely suited to bind to only one substrate in order to undergo the reaction ( Khanacademy.com). Once the enzyme and substrate combine, the enzyme quickly breaks down the substrate. The enzyme, however, is not consumed during this reaction, meaning the enzymes are reuseable. The substrate in this lab is hydrogen peroxide, a toxin found in the cells of all living organisms. Catalase, the enzyme for hydrogen peroxide (H2O2), accelerates the breakdown of hydrogen peroxide into the products of oxygen and water. The chemical equation for this reaction is: 2H2O2 2H2O + O2 The main objective of this lab was to determine how a piece of liver - which contains the enzyme catalase - would react when exposed to hydrogen peroxide (the substrate) in different food items and temperatures. If hydrogen peroxide is added to different food items such as an apple or potato, only a moderate reaction rate will occur compared to the rate of the raw liver. The food item is the independent variable of this lab, thus meaning the food item being tested -raw liver, apple, or potato - will be able to manipulate the outcome of the dependent variable which is the reaction rate. Part two of this lab was to determine the rate of reaction when the catalase was exposed to the hydrogen peroxide in differing temperatures of H2O2 (ice water (0c), room temperature (21c), warm water (37c), and boiled liver). If the liver was placed in each of these temperatures, the liver would have a greater rate of reaction when exposed to 37c hydrogen peroxide, as this is the body's natural tempera ture. By examining the chemical reactions produced when the liver was exposed to the hydrogen peroxide, an accurate analysis of the presence of enzymes as well as their reaction rates in each sample may be gained. Methods Part one of this lab was conducted in order to see if the potato or apple had catalase in them. Before the lab was conducted, materials needed to be gathered. We needed 3 test tubes,a test tube rack, a clean stirring rod, 50 mL of hydrogen peroxide in a small clean beaker, forceps, a piece of liver, a slice