In this experiment, we will explore the properties of fresh potato extract in Phosphate buffer pH6 containing the enzyme polyphenol-oxidase and measure the different concentration of this enzyme activity by observing the production of pink/gold melanin, when 0.1% catechol and phosphate buffer pH6 is mixed into the solution. At this stage of the experiment, we are assuming that all other variables that can act as inhibitors of the enzymatic activity such as temperature or pH levels are under control. Fruits and vegetables are known to have small amounts of catechol and polyphenol-oxidase (enzyme), which are the cause of the production of browning effect in the out-layer skin or liquid of the fruit or vegetable when it is damaged. Polyphenol-oxidase …show more content…
is generally found in plastids or chloroplast in intact cells, which are responsible for enzymatic browning; therefore, when polyphenol-oxidase are in tact they will not brown (Masatsune Murata.t (1997)). In this experiment, we purposely disrupt those intact cells, which lead the enzyme to be mixed with catechol, small amounts found in the vacuoles and cytoplasm, which produce pink/gold melanin in the solution.
In this situation we were able to observe the production of pink/ gold melanin; however it is the amount of polyphenol-oxidase found in each cell and time that reflects the production and color change of melanin. The production and color change of melanin would guide us to determine the rate of the enzymatic activity. The higher amount of melanin being produce will result darker colors, which will lead to higher absorbance, which shows faster enzymatic rate. In addition, polyphenol-oxidase acts as an oxidase that can catalyze the oxidation by binding with molecular oxygen to form OH group. (Samisch 1935) When polyphenol-oxidase is exposed to oxygen, it will immediately catalyze the oxygen to speed up reactions with substrate to produce melanin. In this procedure we also assumed that the substrate in our solution is in excess. Since there is an excess substrate concentration, all the active sites of the enzyme will become occupied with substrate, resulting for the enzyme to become saturated with substrate and the velocity of the chemical reaction has reach its maximal rate, also known as
Vmax. (USE THE BOOOK FRoM Out BIOLOGYBrooker 2014). The Vmax for enzyme-substrate interactions should be represented by deceleration curves because in the beginning of the chemical reaction, they are rapidly producing products (melanin) and will slowly reach equilibrium, when all the enzymes are saturated with substrate. We expect our data to be represented with deceleration curves that will be leveling off at different maximal rates, since we used different amounts of enzyme concentration from our potato extract in phosphate buffer pH6 resulting to each enzyme being saturated at different times and higher concentration of enzyme will lead to higher maximal rates.
Data from Table 1. confirms the theory that as the concentration of glucose increases so will the absorbance of the solution when examined with the glucose oxidase/horseradish peroxidase assay. Glucose within the context of this assay is determined by the amount of ferricyanide, determined by absornace, which is produced in a one to one ratio.1 Furthermore when examining the glucose standards, a linear calibration curve was able to be produced (shown as Figure 1). Noted the R2 value of the y = 1.808x - 0.0125 trend line is 0.9958, which is statistically considered linear. From this calibration curve the absorbance values of unknowns samples can be compared, and the correlated glucose concentration can then be approximated.
In the lab, Inhibiting the Action of Catechol Oxidase we had to investigate what type of enzyme inhibition occurs when an inhibitor is added. Catechol oxidase is an enzyme in plants that creates benzoquinone.Benzoquinone is a substance that is toxic to bacteria. It is brown and is the reason fruit turns brown. Now, there are two types of inhibitors, the competitive inhibitor and non-competitive inhibitor. For an enzyme reaction to occur a substrate has to bind or fit into the active site of the enzyme. In competitive inhibition there is a substrate and an inhibitor present, both compete to bind to the active site. If the competitive inhibitor binds to the active site it stops the reaction. A noncompetitive inhibitor binds to another region
Table 6 shows the results of the biochemical tests. The isolate can obtain its energy by means of aerobic respiration but not fermentation. In the Oxidation-Fermentation test, a yellow color change was produced only under both aerobic conditions, indicating that the EI can oxidize glucose to produce acidic products. In addition to glucose, the EI can also utilize lactose and sucrose, and this deduction is based on the fact that the color of the test medium broth changed to yellow in all three Phenol Red Broth tests. These results are further supported by the results of the Triple Sugar Iron Agar test. Although the EI does perform fermentation of these three carbohydrates, it appears that this bacterium cannot perform mixed acid fermentation nor 2,3-butanediol fermentation due to the lack of color change in Methyl Red and Vogues-Proskauer
The results of this experiment showed a specific pattern. As the temperature increased, the absorbance recorded by the spectrophotometer increased indicating that the activity of peroxidase enzyme has increased.At 4C the absorbance was low indicating a low peroxidase activity or reaction rate. At 23C the absorbance increased indicating an increase in peroxidase activity. At 32C the absorbance reached its maximum indicating that peroxidase activity reached its highest value and so 32 C could be considered as the optimum temperature of peroxidase enzyme. Yet as the temperature increased up to 60C, the absorbance decreased greatly indicating that peroxidase activity has decreased. This happened because at low temperature such as 4 C the kinetic energy of both enzyme and substrate molecules was low so they moved very slowly, collided less frequently and formed less enzyme-substrate complexes and so little or no products. Yet, at 23 C, as the temperature increased, enzyme and substrate molecules
Living organisms undergo chemical reactions with the help of unique proteins known as enzymes. Enzymes significantly assist in these processes by accelerating the rate of reaction in order to maintain life in the organism. Without enzymes, an organism would not be able to survive as long, because its chemical reactions would be too slow to prolong life. The properties and functions of enzymes during chemical reactions can help analyze the activity of the specific enzyme catalase, which can be found in bovine liver and yeast. Our hypothesis regarding enzyme activity is that the aspects of biology and environmental factors contribute to the different enzyme activities between bovine liver and yeast.
Is there a difference in the rate of reaction of catalase activity between pinto beans and carrots? Based on our research, we believe that the catalase activity in pinto beans will increase more relative to the catalase activity in whole carrots because pinto beans are higher in protein. We conducted an experiment to test our hypothesis that if we increase the hydrogen peroxide concentration then we will see higher kinetic saturation in pinto beans over whole
The purpose of this experiment was to see if phenylthiourea (PTU) is a non-competitive or competitive inhibitor. Catechol, a phenolic compound found in the potato extract used will play the part of the substrate. Competitive inhibitors are known to bind to the active site of an enzyme and mimic the job of a substrate. This in turn causes the substrate to compete for a position at the active site and increase the concentration of substrate but the inhibitor is still at a constant level. If PTU were a competitive inhibitor the test tube carrying the extract would turn dark brown. Non- competitive inhibitors are known to bind on the enzyme and prevent the substrate from attaching
This experiment was conducted to determine the effects of pH and temperature on peroxidase from a potato. The optimum temperature for peroxidase was determined to be 23°C, because it had a rate of absorbance of 0.3493, higher than the other temperatures evaluated. A temperature of 48°C is inefficient of speeding up peroxidase activity because its rate of absorbance was 0.001.
In this work, the mechanical and barrier properties were examined for Polypropylene (PP) film in which the surface of the film was modified by Oxygen plasma treatment. The PP film was treated in various intervals of time of 60 s, 120 s, 180 s, 240 s and 300 s with three various RF power settings of 7.2 W, 10.2 W, 29.6 W. The contact angle was measured to characterize the wettability. The oxygen functional groups were generated on the surface of oxygen modified PP which was observed by Fourier transform infrared spectroscope and it was resulted in the improvement of wettability. The surface morphology and roughness of the PP films before and after the oxygen plasma treatment was analyzed by Atomic Force Microscopy (AFM). It was found that the roughness of
Abstract: Enzymes are catalysts therefore we can state that they work to start a reaction or speed it up. The chemical transformed due to the enzyme (catalase) is known as the substrate. In this lab the chemical used was hydrogen peroxide because it can be broken down by catalase. The substrate in this lab would be hydrogen peroxide and the enzymes used will be catalase which is found in both potatoes and liver. This substrate will fill the active sites on the enzyme and the reaction will vary based on the concentration of both and the different factors in the experiment. Students placed either liver or potatoes in test tubes with the substrate and observed them at different temperatures as well as with different concentrations of the substrate. Upon reviewing observations, it can be concluded that liver contains the greater amount of catalase as its rates of reaction were greater than that of the potato.
The independent variable for this experiment is the enzyme concentration, and the range chosen is from 1% to 5% with the measurements of 1, 2, 4, and 5%. The dependant variable to be measured is the absorbance of the absorbance of the solution within a colorimeter, Equipments: Iodine solution: used to test for present of starch - Amylase solution - 1% starch solution - 1 pipette - 3 syringes - 8 test tubes – Stop clock - Water bath at 37oc - Distilled water- colorimeter Method: = == ==
Enzymes are a catalysts that speed up a chemical reaction inside of a cell without being consumed or changed by the reaction. (Wright, W. 2015) Enzymes catalyse reactions by lowering the activation energy that is required for the reaction to occur. (Nature, 2012) In this experiment we will be using Succinate dehydrogenase which is an enzyme that has been extracted from chicken hearts, succinate dehydrogenase is an enzyme of the TCA cycle (citric acid cycle) and involves the catalyses the oxidation of succinate, this means there is a loss of 2 hydrogen atoms. The aims of this experiment are to use 6-dichlorophenolindophenol (DPIP) as a hydrogen acceptor. When DPIP is blue it is in a oxidised state, but when it accepts 2 hydrogen atoms it will become colourless, the disappearing of colour indicates that a reaction is occurring. After the colour is gone we use the time taken to work out the rate of the reaction. in this experiment we will
Enzyme peroxidase is essential in any cell metabolic reaction as it breaks down the harmful hydrogen peroxide to harmful products in the body. The report analyzed its effect on changes in temperatures by determining the optimum temperatures and the effects of its reversibility. Through the method of extracting the enzyme by blending it with potato tissue in phosphate buffer, the effects were analyzed on the effect of the dye guaiacol and the activity measured under different temperatures. The optimum temperature was obtained at 22.20C and above this temperature, the enzyme was denatured. Conclusively, increase in temperature increases
Despite of general properties of enzymes, the properties also varies from where it comes from and how it been produced. For instance, the enzymatic saccharification method in lignocellulosic bioethanol is generated by hydrolyzing cellulose and hemicelluloses. This method gets high attention because of its higher theoretical yield compared to other methods (Taneda et al., 2012). Acremonium cellulolyticus with high activities of cellulase, amylase and pectinase enzymes allow it for the easy separation of solids/liquids in potato pulp, resulting in high saccharification efficiency and a high recovery rate of products (Gao et al., 2014). On the other hand, Enzyme-modified carboxymethyl starch (ECMS) is beneficial in enhancing water holding capacity, emulsion stability and improving sensory characteristics of sausages with a declined fat content (Luo and Xu, 2011). Lipases and phospholipases of dormant cotton seeds have stability in heat, various media and nature of the hydrolysis of the lipids properties (Rakhi...
It changes from blue to red with acids but loses its colour in the presence of certain chemicals, one of which is vitamin C. DCPIP solution can be used to test for the presence of vitamin C in foods. Hypothesis Orange juice has the highest content of vitamin C. Citrus fruits have a higher content of vitamin C. The orange and lemon juice contain more vitamin C than the pineapple juice. Furthermore, as lemons are more acidic than oranges, I predict that the orange juice will contain more vitamin C than the lemon juice. Vitamin C affects, the ph the more vitamin C the higher the ph. Variables Independent Variables Different fruit juices (Pineapple, orange and lemon).