Enzyme Lab
“Enzymes are catalysts that speed up chemical reactions without being used up in the process” (Leady). A catalyst helps speed up a chemical reaction without being changed during the reaction. Enzymes are specific meaning that they can work with only a specific set of chemical reactions. Most enzyme names end in -ase. The shape of a protein is very important in its function for the reaction. The molecule the enzyme works on is called a substrate. In order for this enzyme to work on this reaction the substrate must first fit into an activation site. When an enzyme binds to its substrate, it is called an enzyme-substrate complex. The resulting chemicals from the reaction are called the products. Enzymes can be affected by a few
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All enzymes work best at a specific pH making the reaction better. A few examples of enzymes and their pH level are Pepsin and Trypsin. Pepsin is a stomach enzyme works best at a pH of 2, which is acidic. Trypsin and many other enzymes of the small intestines work better at a higher pH which is basic. “By increasing the amount of enzyme or substrate molecules is known to increase the concentration to the solution”(Effect). As the amounts of enzymes are increasing in the reaction, the rate of the reaction is also increasing. Furthermore, as the amount of the substrate is increasing, the reaction rate increases up to the point where the enzyme is “fully occupied” and then the rate levels off.
Hypothesis/prediction:
If the temperature in the solution of the enzyme peroxidase increases, next the rate of peroxidase will also rise because the warmer the solution, the faster the molecules move, thus causing increased collisions between substrate and enzyme. If the temperature in the solution decreases, the rate of reaction will decrease because a colder solution forces molecules to move a lot slower, causing the amount of collisions between enzyme and substrate to decrease.
Methods:
For this experiment, we utilized the lab manual "Basics of Life Science" by Brenda
In this lab or experiment, the aim was to determine the following factors of enzymes: (1) the effects of enzymes concentration the catalytic rate or the rate of the reaction, (2) the effects of pH on a particular enzyme, an enzyme known and referred throughout this experiment as ALP (alkaline phosphate enzyme) and lastly (3) the effects of various temperatures on the reaction or catalytic rate. Throughout the experiment 8 separate cuvettes and tubes are mixed with various solutions (labeled as tables 1,3 & 4 in the apparatus/materials sections of the lab) and tested for the effects of the factors mentioned above (concentration, pH and temperature). The tubes labeled 1-4 are tested for pH with pH paper and by spectrophotometer, cuvettes 1a-4a was tested for concentration and cuvettes labeled 1b-4b was tested for temperature in four different atmospheric conditions (4ºC, 23ºC, 32ºC and 60ºC) to see how the enzyme solution was affected by the various conditions. After carrying out the procedures the results showed that the experiment followed the theory for the most part, which is that all the factors work best at its optimum level. So, the optimum pH that the enzymes reacted at was a pH of 7 (neutral), the optimum temperature that the reactions occurs with the enzymes is a temperature of 4ºC or
Pepsin is an enzyme that works in the stomach and has an optimal pH between pH 1 and 4 or in acidic conditions. From our graph it can be seen that that the lowest mean percentage light transmission for pepsin is when the buffer has a pH of 2. Trypsin is an enzyme that works in the small intestine and has an optimum pH between pH 7 and 8 or in neutral conditions. From our graph it can be seen that the lowest mean percentage light transmission for trypsin is when the buffer has a pH of 8.
Enzyme catalysis is dependant upon factors such as concentration of enzyme and substrate, temperature and pH. These factors determine the rate of reaction, and an increase in temperature or pH above the optimum will
pH - Enzymes also have an optimum pH level. The pH of a solution affects the enzyme's secondary and tertiary structures. These bonds make the shape of an enzyme's active site. So, if these bonds are broken, the shape of the active site changes and is distorted. If there is no active site, there is no reaction resulting in no products. If the enzyme is put in a pH that is very different from the optimum pH, it can cause the enzyme to denature.
Enzymes are types of proteins that work as a substance to help speed up a chemical reaction (Madar & Windelspecht, 104). There are three factors that help enzyme activity increase in speed. The three factors that speed up the activity of enzymes are concentration, an increase in temperature, and a preferred pH environment. Whether or not the reaction continues to move forward is not up to the enzyme, instead the reaction is dependent on a reaction’s free energy. These enzymatic reactions have reactants referred to as substrates. Enzymes do much more than create substrates; enzymes actually work with the substrate in a reaction (Madar &Windelspecht, 106). For reactions in a cell it is
These results show how temperature of extreme high, or low affects enzyme activity. The highest rate of enzyme activity occurred at 37 Cº. Anything that was hotter or cold than 37 Cº slowed the reaction rate. As I thought, 100 degrees would denature the enzyme, and that was the case. The data provided shows exactly what temperatures enzymes work best, and worst. The objective was achieved as we discovered the different reaction rates under different temperatures. The results are reliable, as we know enzymes do not work well when under extreme heat or denaturation occurs. What I learned in this experiment was that enzymes don’t work well under cold temperatures because they tend to move slower. My hypothesis did not quite match, because I thought they work best at lower temperatures.
Enzymes are catalysts that function to speed up reactions; for example, the enzyme sucrose speeds up the hydrolysis of sucrose, which breaks down into glucose and fructose. They speed up reactions but are not consumed by the reaction that is taking place. The most important of the enzyme is the shape as it determines which type of reaction the enzyme speeds up. Enzymes work by passing/lowering and energy barrier and in doing so; they need to bind to substrates via the active. Once they do, the reaction speeds up so much more quickly than it would without the enzyme. Coenzymes and cofactors aid the enzyme when it comes to binding with the substrate. They change the shape of the active site so the substrate can bind properly and perform its function.
In addition to an optimal temperature, every enzyme also has optimal PH values at which it is the most active. The optimal PH value for most enzymes fall in the range of PH 6-8 (close to neutral PH 7); however some digestive enzymes in the human stomach work best at very acidic PH of 2.
Changes in pH also alter an enzyme’s shape. Different enzymes work best at different pH values. The optimum pH for an enzyme depends on where it normally works. For example, intestinal enzymes have an optimum pH of about 7.5 whereas enzymes in the stomach have an optimum pH of about 2.
The graph below shows the effect of temperature on relative rate of action of enzyme X on a protein.
pH affects enzymes stability and activity but the effects that they have will vary between different enzymes. If an enzyme is exposed to high temperatures it will denature. Inhibitors come in two different forms, competitive and noncompetitive. Competitive inhibitors have complementary shapes to the active site of the enzyme, which means that it can bind to it, blocking the substrate. Noncompetitive inhibitors bind to another part of the enzyme which changes the shape of the active site and therefore makes it impossible for the substrate to bind to the enzyme.
Organisms cannot depend solely on spontaneous reactions for the production of materials because they occur slowly and are not responsive to the organism's needs (Martineau, Dean, et al, Laboratory Manual, 43). In order to speed up the reaction process, cells use enzymes as biological catalysts. Enzymes are able to speed up the reaction through lowering activation energy. Additionally, enzymes facilitate reactions without being consumed (manual,43). Each enzyme acts on a specific molecule or set of molecules referred to as the enzyme's substrate and the results of this reaction are called products (manual 43). As a result, enzymes promote a reaction so that substrates are converted into products on a faster pace (manual 43). Most enzymes are proteins whose structure is determined by its sequence of its amino acids. Enzymes are designed to function the best under physiological conditions of PH and temperature. Any change of these variables that change the conformation of the enzyme will destroy or enhance enzyme activity(manual, 43).
Introduction Background Information An enzyme is a biological catalyst. This means that it speeds up the rates of reactions, particularly those that are biological. The enzyme does not get used up in the reactions which it catalyzes. Instead, it remains unchanged such that it can be reused in similar reactions in the future.
generally act as a catalase that initially bring about a chemical reaction.” Enzymes play an
Almost all enzymes need specific conditions for them to function. The conditions include temperature, pH level, and concentration of salt. Enzymes have optimal conditions. If they are changed, the enzyme may denature and deactivate. If that happens, the enzyme would not be able to catalyze the reaction, and the reaction rate would decrease (Worthington 2010).