P-Nitrophenol Lab Report

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

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

The isosbestic point of the acid (pH6) and basic forms (pH10) of para Nitrophenol (PNP) was expected at 350nm. As you can see in figure 2, the graph shows the intersection of 2 curves at ~350nm, which is matched with the literature value. Also, the pKa of PNP was expected 7.15 at room temperature. Refer to figure 3, the pKa is estimated to be 7.15-7.2, which very close to the literature value. In addition, the lab was succeeded in illustrating the use of a spectrophotometry to analyze concentrations of chemical substance. The absorbances of 2 unknowns were felt on the standard curve as the expectation (refer to table 4). The minimum absorbance of the known standards was 0.193 and the maximum is 1.830. The absorbance of the unknown

The purpose of this experiment was to simply measure oxygen production rates released from decomposed hydrogen peroxide under different conditions (concentration of enzymes, temperature, and PH level).

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.

Background and Introduction: Enzymes are proteins that process substrates, which is the chemical molecule that enzymes work on to make products. Enzyme purpose is to increase the rate of activity and speed up chemical reaction in a form of biological catalysts. The enzymes specialize in lowering the activation energy to start the process. Enzymes are very specific in their process, each substrate is designed to fit with a specific substrate and the enzyme and substrate link at the active site. The binding of a substrate to the active site of an enzyme is a very specific interaction. Active sites are clefts or grooves on the surface of an enzyme, usually composed of amino acids from different parts of the polypeptide chain that are brought together in the tertiary structure of the folded protein. Substrates initially bind to the active site by noncovalent interactions, including hydrogen bonds, ionic bonds, and hydrophobic interactions. Once a substrate is bound to the active site of an enzyme, multiple mechanisms can accelerate its conversion to the product of the reaction. But sometimes, these enzymes fail or succeed to increase the rate of action because of various factors that limit the action. These factors can be known as temperature, acidity levels (pH), enzyme and/or substrate concentration, etc. In this experiment, it will be tested how much of an effect

Samples of benzophenone, malonic acid, and biphenyl were each tested with water, methyl alcohol, and hexane. Benzophenone was insoluble in water as it is nonpolar while water is highly polar. Benzophenone was soluble in methyl alcohol, dissolving in 15 seconds, because methyl alcohol is intermediately polar as benzophenone is nonpolar. Methyl alcohol is polar but not as much as water. Thus, the nonpolar benzophenone was soluble in methyl alcohol. Benzophenone was partially soluble in hexane because hexane is nonpolar as is benzophenone. Thus, benzophenone was dissolved in hexane. Malonic acid was soluble in water because both malonic acid and water are polar. It took 25 seconds for malonic acid to dissolve in water. Malonic acid was soluble in methyl alcohol because malonic acid is polar and methyl alcohol is intermediately polar, allowing malonic acid to dissolve in the methanol in 15 seconds. Malonic acid was insoluble in hexane because hexane is nonpolar while malonic acid is polar. Biphenyl was insoluble in water as water is highly polar whilst biphenyl is nonpolar. Biphenyl was partially soluble in methanol which is intermediately polar whilst biphenyl is nonpolar, allowing it to dissolve a little. Biphenyl was soluble in hexane because both biphenyl and hexane are nonpolar molecules. Biphenyl dissolved in hexane in 10 seconds.

Within the experiment, pure catechol was mixed with different concentrations of catechol oxidase and the rate at which each solution produced benzoquinone was measured. The amount of benzoquinone made throughout the trials was measured by using a colorimeter to measure the level of “brownness” of the liquid. The colorimeter worked by shining a light through the liquid and then measuring that light on the other side to see how much of it was absorbed. In this experiment, absorbance of blue light was measured because blue light is absorbed by the color brown. The amount of blue light absorbance was measured every 15 seconds for five minutes. Because enzymes speed up reactions, more enzymes would cause the reaction to be even faster.1

Table 2: Consists of color extract taken from a red cabbage for a natural indicator. The pH reading that was measured by using the pH meter and the result of the pH reading to determine whether the solution was acidic or basic.

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.

2. (5 pts) List and explain the names and affiliations of the various characters/stakeholders in this story – I’m looking for us to use the story to map out the complexities that are generally associated with solving public health puzzles – the stakeholders you list and explain here should apply to many of the cases we consider going forward.

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.

The experiments involved PH buffers of different pH were added to potato juice, water, and the enzyme catecholase. The mixture was then subjected to spectrophotometer at a wavelength of 420nm taking the absorbance readings. In the second experiment, a phosphate buffer of PH 7.0 was used in different measures together with different measurement of potato juice and the enzyme catecholase then subjected to the spectrophotometer at a wavelength of 420nm. The data collected inform of table and analyzed using descriptive statistics such as line graph and later interpreted, showing that PH and enzyme concentration do affect the rate of enzyme reaction

After measuring equal amounts of distilled water and either adding or subtracting catechol which we referred to as the substrate some reactions was seen immediately. After which we were able to get data that supported my original hypothesis that in the addition of substrate and an enzyme the reaction would be present in varying degrees dependent on whether a temperature change was provided or not. In the second part of the experiment we were testing the inhibition action of Catechol Oxidase at different levels in several tubes of varying samples of potato extract, phenylthiourea (PTU) and distilled water. The experiment showed that (PTU) bonded with the extract and the water causing a reaction whereas there was no reaction in tube # 1 where there was an equal amount of everything in the tube. And test tube # 3 was the control tube where the (PTU) was eliminated as to observe if there was any reaction at all. Of course with the whole experiment we had to be very careful as to add the catechol last to ensure no premature reaction. It was hypothesized that (PTU) is a non -competitive inhibitor and doubling the substrate will have no reversal effect.

In this experiment, the pKa, dissociation constant, of 2-naphthol was determined by measuring the UV-visible absorption spectra of solution of the acid at different pH values.