Introduction The organic compound catecholase is commonly found in plants and consists of two substrates called catechol and oxygen. When these substrates react with each other they form a brown color, often seen in vegetables and fruits left out after being cut open. (Wahlert and Holland, 1999) This reaction is why when a potato is cut open and left to sit, it will begin to brown. During the genetic mutation of potatoes, scientists can limit the amount of the substrate which causes less severe browning or no browning in potatoes. (Adams and Brown, 2007). The potato contains enzymes in which the catechol reacts with and it speeds the process up. If catecholase were left alone and without a catalyst (enzyme) the reaction would take much longer. …show more content…
The control tube is tube number three because it contained the same ingredients as that of the first experiment where we determined that when catechol reacts with potato extract it turns brown. In test tubes one and two a different amount of catechol was added. This is because we needed to determine what kind of inhibitor the PTU was. Because there was no change in color with either test tube one or two, we found that PTU was a non-competitive inhibitor. Discussion The hypothesis created at the beginning of this lab was that PTU is a non-competitive inhibitor and the color of the solution would remain constant after the inhibitor was added due to it changing the shape of the enzyme completely and not allowing the catechol substrate to react with the potato enzyme. During the lab we found that PTU was a non-competitive inhibitor, due to no change in the color of the solution after the inhibitor was added. Our results were conclusive with our hypothesis but our hypothesis was incorrect as were our lab results. According to other studies done on the inhibitor phenylthiourea, it is in fact a competitive inhibitor and our experiment was incorrectly tested. The addition of the extra catechol was supposed to have sped up the reaction with the enzyme and force the inhibitor out of the enzymes active site. If there was more time allowed to observe any possible color changes the results would have been more conclusive and our results more accurate. In other
The purpose of this experiment was to analyze the effects of the variables: temperature, pH, and enzyme concentration, on the enzymatic reaction rate of catalase and the level at which its products are released, measuring the rate of absorption using the indicator solution guaiacol and a spectrophotometer to develop a hypothesis of the ideal conditions for these reactions. My hypothesis is that the extremes in concentration, temperature and pH will negatively affect the Au rate. This experiment used 11 solutions contained in cuvettes. Each cuvette, once mixed, is placed in spectrophotometer and then a reading taken every 20 seconds. Cuvettes 1, 8, and 10 are used as blanks to zero out the spectrophotometer.
The competitive inhibitor that was added was lactose. We predicted this because competitive inhibitors block and bind to the active site so it will slow down the binding of the desired substrate. An alternative hypothesis that came up was that the reaction of substrate would stay consistent as if no inhibitor was added. The enzyme could reject the inhibitor if it does not fit in the active site, causing the substrate to bind as it normally would. Our results showed that with the addition of lactose, the reaction did slow down a considerably
We hypothesized that whenever the inhibitor was introduced into the reaction, the absorbance value would be lower than the baseline enzyme reaction. We believed that this was due to the inhibitor competing with the substrate for active site on the enzyme or altering the configuration of the enzyme depending on the inhibition type. If hydroxylamine was a competitive inhibitor, it would bind to the active site which prevents the substrate from binding. However, if it was noncompetitive inhibition, then the hydroxylamine would bind to the allosteric site of the peroxidase. and the substrate may or may not still be able to bind to the active site.
This is because a substrate has specific chemical properties that satisfy the chemical properties of the active site. Enzymes quicken reactions by decreasing the amount of energy needed for the reactant to undergo a specific reaction by providing an alternative reaction pathway. In this experiment, the enzyme catalase will be used. The enzyme catalase is commonly found in animal and plant cells, but a substantial amount is found in liver.
This is indicated as the graph shows that the initial reaction rate for pH 7 was 0.143 %O2/s compared to 0.047 and 0.053 for pH 6 and 8 respectively. Additionally, Figure 3 indicates that as the pH increases or decreases from 8 and 6 respectively the initial rate of reaction decreases marginally. This is known as the initial rate of reaction for pH 4 and 10 was 0.036 and 0.035 %O2/s, indicating an unsubstantial difference in the initial rate of reaction; for pH 4 and 6 of 0.011 %O2/s and pH 8 and 10 of 0.018 %O2/s. As the pH deviates from 7 the initial rate of reaction decreases as the optimal pH for catalase is 7. As the pH increases or decreases the concentration of hydrogen and hydroxide ions in the solution are altered. These ions alter the shape of the enzyme diminishing the ability for hydrogen peroxide to bind with the active sight of the catalase enzyme in turn decreasing
Each enzyme is specific for a certain reaction due to the special 3D structure of its amino acid sequence. This laboratory
The enzyme found in different conditions which its specific reaction rate. Variation in enzyme concentration, variation in pH, variation in temperature, and the effect of different concentrations of inhibitors were all tested. The enzyme concentration increased the reaction rate. An optimum pH and temperature were found for the enzyme, outside of this optimum the reaction rate would be lower. The correct name is the catalase enzyme.
Materials and Methods: For the chromatographic separation of plant pigments, pieces of spinach were ground with acetone to produce a watery extract. A line of extract was applied 1 cm from the bottom of a strip of chromatography paper. The line dried and the extract was reapplied. Once that dried, the paper was placed into a jar containing a small amount chromatography solvent (small enough that the line was not drowned by the solvent) which is made of 1 part acetone and 9 parts petroleum ether. The lid was placed on the jar and was only removed once the pigments had separated and the solvent had almost reached the top.
The substrate for the sweet potato catechol oxidase is N-phenylthiourea. In comparison to the possible substrates for catechol they both have hydrogen acceptor sites that can be used to hydrogen bond in the active site of the enzyme. Along with hydrogen bonding there may be some ionic bonding between some metal atoms in the active site of the enzyme and the substituents coming off of the benzene ring.
The method used was reliable and increased accuracy in the experiment, making it a fair test. This is proven throughout out the experiment because of many reasons such as the controlling the temperature. We did this by making sure the temperature of all enzymes tested, were consistent and had the same temperature, by putting the potato enzymes (Peroxidase) in a boiling tube then in a water bath to at a temperature of 20*c. This ensured a greater accuracy in the results, because if the temperature of some enzymes were higher than the rest, then the rate of reaction for those enzymes would have been faster as particles would move faster as they heat up speeding up the process. Our method was done at 20*c because this is close to room temperature
The enzyme would be inactivated. 2. The catalase which is the enzyme breaks down the substrate hydrogen peroxide forming the product water and oxygen. There is less hydrogen peroxide concentration as time is increased due to break down of the substrate. As time is increased more oxygen is given off, more water is formed resulting in a decrease in color intensity.
5 water bath were set up each to10 °C. (5 were used do the experiment faster) 5 cm3 of starch solution were added into the 5 test tubes that were labeled test tubes. Then 5 cm3 of amylase enzyme was added into the other 5 test tubes that were labeled. Put one of the starch solution test tube (preferably the one labeled 1) and one of the test tube containing amylase into the water bath (10 °C).
The purpose of this project is to further test the effect of pH levels, and how they affect the production of enzymes. The hypothesis for this experiment was the more basic the ph buffer the high the activity of the enzyme. The more acidic the pH buffer the less activity of the enzyme. The first time the experiment was done with only three pH levels that were tested. That helped find the range of pH levels that were needed to test the second time.
At last, at 95°C, or 85ºC, the enzyme activity is showed at being in its greater temperature. From black at 0 minutes, the color became bright yellow at 10 minutes, which specify the optimal temperature for
There was a big difference between result shows that the result obtained was not precise and reliable. One of the chicken liver could be smaller causing lesser catalase to be released whereas another chicken liver could be larger therefore more catalase was released. When there was more enzyme available , more hydrogen peroxide could bind to the active sites of catalase leading to the higher rate of reaction calculated. One way to improve on this method is to weight the chicken liver after cutting it with a smaller knife. By weighing the chicken liver after cutting into 1 cm3 , the mass of chicken liver can be measured and avoid having different sizes of chicken liver which will cause the imprecise result in the experiment.