The Influence of pH on the Rate of Catecholase-Catalyzed Reaction
Lab Session - 6
Prepared by: Yordanos Fente
Lab Partners: Ariana Page Cristy Farrar
Date Performed:11/01/2016
Date Submitted:11/15/2016
Prof. Ashley Bregman
Introduction Without enzymes the existence of life is questionable since all metabolic processes in the cell cannot occur at a faster rate enough to sustain life. All the essential biological reactions in living things depend on enzymes’ catalytic activity. Enzymes are usually proteins, though some Ribonucleic Acid (RNA) molecules act as enzymes too, that speed up the rate of biological reactions without being consumed by the reaction. (Reece,2016, p.83) For instance, the presence of enzymes in the conversion of DNA to RNA allows a reaction that would otherwise take millions of years to occur in milliseconds. Like all catalysts, enzymes accelerate the rate of reaction by lowering the activation energy that is the amount of energy that must be put in for the reaction to begin. (Reece,2016, p.83)
To catalyze a reaction, an enzyme will bind to one or more reactant molecules. These molecules are the enzyme 's substrates. The part of the enzyme where the substrate binds is called the active site. In enzymes that are proteins, the active site gets its properties from the amino acids it 's built out of. These amino acids may have side chains that are acidic or basic. The set of amino acids
For enzymes to be useful in a reaction, the substrate needs to bind with the enzymes active site. The active site is specific for a
Enzymes speed up metabolic reactions necessary for life. Without them certain vital processes would not take place and the body would be unable to function.
Enzymes are biological catalysts that speed up chemical reactions, without being used up or changed. Catalase is a globular protein molecule that is found in all living cells. A globular protein is a protein with its molecules curled up into a 'ball' shape. All enzymes have an active site. This is where another molecule(s) can bind with the enzyme. This molecule is known as the substrate. When the substrate binds with the enzyme, a product is produced. Enzymes are specific to their substrate, because the shape of their active site will only fit the shape of their substrate. It is said that the substrate is complimentary to their substrate.
Lab six requires students to observe the effects of pH and enzyme concentration on catecholase activity. Enzymes are organic catalysts that can affect the rate of a chemical reaction depending on the pH level and the concentration of the enzyme. As pH comes closer to a neutral pH the enzyme is at its greatest effectiveness. Also at the absorbance of a slope of 0.0122 the enzyme is affected greatly. The pH effect on enzymes can be tested by trying each pH level with a pH buffer of the same pH as labeled as the test tube and 1mL of potato juice, water, and catechol. This is all mixed together and put in the spectrophotometer to test how much is being absorbed at 420nm. As the effect on enzyme concentration can be tested almost the same way. This part of the exercise uses different amounts of pH 7-phosphate buffer and potato juice, and 1mL of catechol mixed together in a test tube. Each substance is put in the spectrophotometer at a wavelength set tot 420nm. The results are put down for every minute up to six minutes to see how enzyme concentration affects reaction rate. The results show that the pH 8 (0.494) affects the enzyme more than a pH of 4 (0.249), 6 (0.371), 7 (0.456), and 10 (0.126). Also the absorbance is greatest at a slope of 0.0122 with test tube C that has more effect on the reaction rate, than test tube A, B, and D.
B. Catalysis occurs on a specific site on the enzyme (the active site). The active site is usually less than 5% of the surface area of the protein, and is always in a cleft. The rest of the molecule serves to present the active site in a three dimensional structure that is capable of binding substrate and catalyzing the reaction. Binding to a substrate is very specific, and involves ionic interactions, H bonds and van der Waals forces.
The independent variable in this investigation is pH. Each individual enzyme has it’s own pH characteristic. This is because the hydrogen and ionic bonds between –NH2 and –COOH groups of the polypeptides that make up the enzyme, fix the exact arrangement of the active site of an enzyme. It is crucial to be aware of how even small changes in the
The purpose of this investigation is to discover the effect of pH on the activity of catalase, an enzyme which plays the integral role of converting hydrogen peroxide into water and oxygen, and discover which pH level it will work at the most efficient rate (the optimum). The original hypothesis states that that the optimum would be at a pH is 7, due to the liver, where catalase usually resides, being neutral. The experiment consists of introducing the catalase to hydrogen peroxide, after exposure to certain solutions; hydrogen peroxide, water and hydrochloric acids, all containing the adjusted pH, and measuring the height of froth formed, an observable representation of the activity of the enzyme. The final data indicated that
Enzymes are biological catalysts, which accelerate the speed of chemical reactions in the body without being used up or changed in the process. Animals and plants contain enzymes which help break down fats, carbohydrates and proteins into smaller molecules the cells can use to get energy and carry out the processes that allow the plant or animal to survive. Without enzymes, most physiological processes would not take place. Hundreds of different types of enzymes are present in plant and animal cells and each is very specific in its function.
Living cells within our bodies perform an abundance of chemical reactions very speedily because of the participation of enzymes. Enzymes are biological catalysts that speed up a chemical reaction without being depleted or altered in the reaction (Garrette & Grisham, 1999). The
Enzymes are a key aspect in our everyday life and are a key to sustaining life. They are biological catalysts that help speed up the rate of reactions. They do this by lowering the activation energy of chemical reactions (Biology Department, 2011).
Abstract: Enzymes, catalytic proteins that at as catalysis which makes the process of chemical reactions more easily. There are two main factors that actually affects enzymes and their functions which are temperature and pH. Throughout this experiment, the study how pH and peroxidase affects each other and the enzyme was made. The recordings of how the enzymes responded when it was exposed to four different pH levels to come up with an optimum pH which was predicted in the hypothesis and the IRV at the end.
“Enzymes are proteins that have catalytic functions” [1], “that speed up or slow down reactions”[2], “indispensable to maintenance and activity of life”[1]. They are each very specific, and will only work when a particular substrate fits in their active site. An active site is “a region on the surface of an enzyme where the substrate binds, and where the reaction occurs”[2].
There are thousands of chemical reactions that occur in an organism that make life possible. Most of these chemical reactions occur too slowly on their own. Enzymes are protein catalysts that speed up chemical reactions in a cell. Catalysts are not changed by the reactions they control, and are not used up during the reaction. Enzymes therefore, can be used over and over again. Enzymes are large complex proteins made by the cell and allow chemical reactions to take place at the temperature of the cell. These catalysts are needed in only very small amounts because a single enzyme molecule can complete the same reaction thousands of times in one minute.
Enzymes are proteins that act as catalysts and help reactions take place. In short, enzymes reduce the energy needed for a reaction to take place, permitting a reaction to take place more easily. Some enzymes are shape specific and reduce the energy for certain reactions. Enzymes have unique folds of the amino acid chain which result in specifically shaped active sites (Frankova Fry 2013). When substrates fit in the active site of an enzyme, then it is able to catalyze the reaction. Enzyme activity is affected by the concentrations of the enzymes and substrate present (Worthington 2010). As the incidence of enzyme increases, the rate of reaction increases. Additionally, as the incidence of substrate increases so does the rate of reaction.
Enzymes, proteins that act as catalysts, are the most important type of protein[1]. Catalysts speed up chemical reactions and can go without being used up or changed [3] Without enzymes, the biochemical reactions that take place will react too slowly to keep up with the metabolic needs and the life functions of organisms. Catecholase is a reaction between oxygen and catechol [2]. In the presence of oxygen, the removal of two hydrogen atoms oxidizes the compound catechol, as a result of the formation of water [2]. Oxygen is reduced by the addition of two hydrogen atoms, which also forms water, after catechol is