The marketing and storage of perishable foodstuffs can be delayed by using treating them with methods that will slow or halt enzymatic activity. We experimented as to whether or not varied concentrations of sodium chloride, NaCl had any effect on the activity of catechol oxidase, an enzyme found in potatoes. A serial salt-water dilution was made, a potato homogenate made, and buffered catechol oxidase added. The solutions were placed in a spectrophotometer and the light absorbance for each recorded. The higher concentrations of salt, around 20% solution, reduced enzyme activity. We concluded that general increases in the amount of salt molecules in the solution negatively affected the enzymatic activity of the catechol oxidase and markedly …show more content…
Because catechol oxidase is an enzyme, various environmental conditions are able to affect its condition and activity levels. Salt is an ionic compound that dissolves completely in water, pervading the solution with oppositely charged sodium and chlorine ions. These ions interact with the charged R-groups of the protein catechol oxidase and may denature it. Research conducted on apples, a similar testing subject to potatoes as the same enzyme is present in the fruit, has revealed that low levels of salt, between .2 and 1 g/L allowed for the most browning. Concentrations between .05 and 1% inhibit polyphenol oxidase, and concentrations at 20% and above completely inactivate the enzyme according to (insert citation). With this information, it is expected that higher concentrations of salt will significantly lower enzymatic …show more content…
It can be inferred that as sodium chloride, a strong electrolyte, dissolves completely in aqueous solutions, pervading the solution with free sodium and chlorine ions, interferes with the binding of catechol oxidase to the substrate, buffered catechol oxidase. As enzymes are proteins, charged R-groups interact with the oppositely charged ions of salt, altering the enzyme’s shape and rendering it unable to bind. According to (__), the chlorine anion is responsible for the change in enzyme activity. The ions act as noncompetitive inhibitors, binding to sites other than the active site. Because enzyme shape is so specific to its function, even slight interactions are likely to considerably lower its activity. Solutions more concentrated than 20% significantly drop enzyme activity and bring it almost to a halt (Ming Hui Fan et al.,2005). On the other end, our data reflects that too low of a salt concentration may also affect the viability of the enzyme. A 2.5% salt solution exhibited a decrease in activity (Fig. 1) which leads one to believe that the natural salt content of potatoes likely lies around 5%, the optimal concentration
This experiment looked at how substrate concentration can affect enzyme activity. In this case the substrate was hydrogen peroxide and the enzyme was catalase. Pieces of meat providing the catalase were added to increasing concentrations of hydrogen peroxide in order to measure the effect of hydrogen peroxide concentrations on the enzyme’s activity. The variable measured was oxygen produced, as water would be too difficult to measure with basic equipment.
The Effects of Varied Temperatures, pH Values, Enzyme Concentrations, and Substrate Concentrations on the Enzymatic Activity of Catecholase
The role of an enzyme is to catalyse reactions within a cell. The enzyme present in a potato (Solanum Tuberosum) is catechol oxidase. In this experiment, the enzyme activity was tested under different temperature and pH conditions. The objective of this experiment was to determine the ideal conditions under which catechol oxidase catalyses reactions. In order to do this, catechol was catalyzed by catechol oxidase into benzoquinone at diverse temperatures and pH values. The enzyme was exposed to its new environment for 5 minutes before the absorbance of the catechol oxidase was measured at 420 nm using a spectrophotometer. The use of a spectrophotometer was crucial for the collection of data in this experiment. When exposed to hot and cold temperatures, some enzymes were found to denature causing the activity to decrease. Similarly, when the pH was too high or low, then the catechol oxidase enzyme experienced a significant decrease in activity. It can be concluded after completing this experiment that the optimal pH for catechol oxidase is 7 and that the prime temperature is 20º C. Due to the fact that the catechol oxidase was only tested under several different temperatures and pH values, it is always possible to get a more precise result by decreasing the increments between the test values. However, our experiment was able to produce accurate results as to the
Temperature can affect the reaction of catechol oxidase by speeding up or slowing down the reaction. I was able to see what happened to the absorbance after changing the temperature of the catechol oxidase solution. I did this by heating and cooling the solutions to measure the absorbances in hot, cold, warm, and room temperature. Then the data was compared to see how the temperature effected the solution. The catechol oxidase solutions reacted best in room temperature (twenty-three degrees Celsius) and the worst in the cold (zero degrees Celsius). I concluded that temperature really does affect the way catechol oxidase reacts.
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.
The lab leaders and the Punk Rock Warlord prepared three different concentrations of catechol oxidase by extracting potato juice (because it contains lots of catechol oxidase). Pure catechol, a 5mL test tube, 1mL/5mL
Lactose is a sugar that can be put into smaller molecules, glucose and galactose. Lactose is when you are not able to digest milk and dairy meaning that the enzyme lactase that breaks down lactose is not functioning properly. ONPG was used as a substitute for lactase because even though it is colorless it helps show enzyme activity by turning yellow. This experiment measured the absorbance ONPG when exposed to lactase within an environment of different salinity’s. The enzyme, lactase, was obtained by crushing a lactaid pill and then was added into four cuvettes. ONPG and salt solution of different concentrations were added and their levels of absorption was measured by a spectrophotometer. The results showed that higher salt concentrations have a lower level of absorption. There were 4 cuvettes and within those cuvettes that solutions within them were being tested and the results showed the more salt solution added with the lactase the lower the absorbance. The less salt solution there was a higher rate of absorbance. The data supported the hypothesis that with increasing NaCl concentration there would be a decrease in enzyme activity.
Peroxidase is an enzyme found in potatoes that catalyzes the breakdown of hydrogen peroxide, H2O2, into O2 gas and water. We examined the different pH environments that can affect the enzyme activity during the breakdown of H2O2. In order to do this, we added different levels of pH, low, medium, and high, into different test tubes with the enzyme and H2O2, and we then inverted the tube. The amount of O2 gas produced was then measured and recorded. The result was that the higher pH produced more gas, followed by medium pH, then low pH. The enzymes were more active in the pH of about 10. It increased
Catechol, in the presence of oxygen is oxidized by catechol oxidase to form benzoquinone (Harel et al., 1964). Bananas and potatoes contain catechol oxidase that acts on catechol which is initially colorless and converts it to brown (Harel et al., 1964). In this experiment, the effect of pH on the activity of catechol oxidase was conducted using buffers ranging from pH2 to pH10. Two trials were conducted due to the first trial results being altered by an external factor. The results were acquired by taking readings every 2 minutes for 20 minutes from a spectrophotometer and then recorded on to the table. The data collected in the table were then made into graphs to illustrate the influence of pH on the catechol oxidase catalyzed reaction. After analysis, the data revealed that pH did have a significant influence on the enzyme as recorded by absorbance per minute. However, the data was collected was not accurate due to external factors, thus the results are debatable and should be experimented again for validation.
The purpose of this report is to find out the effect of change in the Temperature, PH, boiling, concentration in peroxidase activity. Peroxidase is an enzyme that converts toxic hydrogen peroxide (H2O2) into water and another harmless compound. In this experiment we use, turnips and horseradish roots which are rich in the peroxidase to study the activity of this enzyme. The activity of peroxidase with change in temperature was highest at 320 Celsius and lowest at 40C. The activity of peroxidase was highest at a pH of 7, while it was lowest at pH of 9.Peroxidase activity was very low and constant with boiled extract, while the activity was moderate
Enzymes are high molecular weight molecules and are proteins in nature. Enzymes work as catalysts in biochemical reactions in living organisms. Enzyme Catecholase is found on in plants, animals as well as fungi and is responsible for the darkening of different fruits. In most cases enzymatic activities are influenced by a number of factors, among them is temperature, PH, enzyme concentration as well as substrate concentration (Silverthorn, 2004). In this experiment enzyme catecholase was used to investigate the effects of PH and enzyme concentration on it rate of reaction. A pH buffer was used to control the PH, potato juice was used as the substrate and water was used as a solvent.
In the exercise # 2 we observed the effect of substrate concentration, enzyme concentration, pH and temperature on enzyme activity. All the data showed that once potato extract was added to catechol and water the reaction varied dependent on the level of catechol. As in
In conclusion, my hypothesis proved to be correct seeing as when the temperature rose to 60ᵒC where there was no enzyme activity shown, resulting in the belief that the enzyme was denatured. This is because of the initial rate of reaction increasing due to the increase in temperature. As temperature was increased, the reaction rate of the potato catalyse then happens to also increase due to an optimum temperature, where the reaction rate is at its highest until denaturing within when the enzyme occurs and then reaction rate of the catalyse casually drops off. At first, the higher the temperature the more oxygen is produced as there is a higher chance of the substrate hydrogen peroxide binding with the potato catalyse and so producing oxygen.
The enzyme catechol oxidase, extracted from masticated potato (Solanum tuberosum) lowers activation energy, as it is a catalyst. This enzyme can react with catechol to produce benzoquinone and water. Catechol oxidase is tested against a multitude of phosphate buffers, acidic, neutral and basic pH values, and chilled temperatures to hot temperatures. The purposes of these testes were to determine the optimal temperature and pHs at which catechol oxidase performs at. The method to measure results was the usage of a spectrophotometer (Vernier Spectrouis Plus). The spectrophotometer measures the absorbance levels of the pigment excreted when catechol oxidase undergoes a reaction. The high the absorbance, the more products produced and vise versa. The highest absorbance for the catechol oxidase submitted to different temperatures measured an average 0.6018 nm, when at 20 C. The highest absorbance for the catechol oxidase submitted to different pH values measured two averages of 0.658 at pH 6 and 0.6464 at pH 7. The conclusion taken from the available data explains that the optimal pH for catechol oxidase was between pH 6 and 7 and the optimal temperature was at room temperature at 20C.
This experiment is designed to analyze how the enzyme catalase activity is affected by the pH levels. The experiment has also been designed to outline all of the directions and the ways by which the observation can be made clearly and accurately. Yeast, will be used as the enzyme and hydrogen peroxide will be used as a substrate. This experiment will be used to determine the effects of the concentration of the hydrogen peroxide versus the rate of reaction of the enzyme catalase.