Abstract
The pH of our duodenum fluctuates from acidic (pH 2) to alkaline (pH 7.5), (Woodtli & Werner, 1995). Enzymes such as Trypsin, work in our duodenum to speed up the chemical reactions which break down macromolecules and extract nutrients and energy from the food we eat. Since enzymes change activity depending on pH due to changes in their tertiary structure, we wanted to assess the effects of pH on the Trypsin enzymatic activity. To address our question, we conducted the reaction in which the substrate BAPA and TRIS buffer were mixed with Trypsin extract, and the rate of reaction was measured as product appearance (p-nitroanaline) over time using a spectrophotometer. We conducted 6 replicates for the reactions at pH 4, pH5, pH6, pH7,
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From our data, the optimal pH range for Trypsin was found to be pH 7-10 (over the range of pHs 4-10). We found that the average reaction rate of the Trypsin catalyzed reaction increased significantly each time as we increased the pH from 4 to 5, from 5 to 6, from 6 to 7, from 6 to 8, from 6 to 9 and from 6 to 10, however there is no significant difference between the reaction rates at pHs 7, 8, 9 and 10. We found that at pHs lower than the experimentally determined optimal pH range of Trypsin (7-10), there was a decrease in enzymatic activity compared to the activity at pH 7-10, but at pHs higher than this optimal pH range (up to a pH of 10), there was no significant effect of the pH on the enzymatic activity. Thus according to the results of our experiment, fluctuations in pH (within the range of pH 4-10) in the duodenum would only significantly decrease the trypsin enzymatic activity below optimal, when the pH fluctuates and decreases below a …show more content…
Basic secretions from the pancreas then enter the small intestine to neutralize the pH-decreasing effect of the acidic chyme. Thus these basic and acidic fluid secretions in the duodenum, cause the pH in the duodenum to fluctuate from an acidic pH of 2 to a basic pH of 7.5 (Woodtli & Werner, 1995). We wanted to investigate the question of how these fluctuations of pH in the duodenum affect the activity of the enzyme Trypsin. Enzymes play a very important physiological role in the human body because they speed up the rates of reactions vital to our survival. Enzymes bind to specific substrates and configure their positions, geometry or interactions relative to one another in such a way, that the activation energy required for a reaction to occur is lowered, and thus the reaction rate is increased. The activity of an enzyme depends on many environmental factors such as pH and temperature, because changes in temperature and pH affect the intermolecular interactions between amino acids in the backbone, holding the tertiary structure of the enzyme together. Thus each enzyme has an optimal pH range, below which, and above which its activity declines. Trypsin is an important enzyme that catalyzes the breakdown of specific peptide bonds in the duodenum of the small intestine so that we can extract nutrients and energy from the proteins we eat (Nelson & Cox, 2013). Trypsin is a
4. The stomach maintains a pH of approximately 3 to 5. Do all enzymes function at this pH level? Give an example from one of the exercises.
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
In the experiment we used Turnip, Hydrogen Peroxide, Distilled Water, and Guaiacol as my substances. On the first activity, Effect of Enzyme concentration of Reaction Rate for low enzyme concentration, we tested three concentrations of the turnip extract, and hydrogen peroxide. For the Turnip Extract I used 0.5 ml, 1.0 ml, and 2.0 ml. For hydrogen peroxide we used 0.1 ml, 0.2 ml, and 0.4 ml. We used a control to see the standard, and used a control for each enzyme concentration used. The control contains turnip extract and the color reagent, Guaiacol. We prepared my substrate tubes separately from the enzyme tubes. My substrate tube
The use of multiple test tubes and Parafilm was used for each experiment. Catechol, potato juice, pH 7 phosphate buffer, and stock potato extract 1:1 will be used to conduct the following experiments: temperature effect on enzyme activity, the effect of pH on enzyme action, the effect of enzyme concentration, and the effect of substrate concentration on enzyme activity. For the temperature effect on enzyme activity, three test tube were filled with three ml of pH 7 phosphate buffer and each test tube was labels 1.5 degrees Celsius, 20 °C, and 60 °C. The first test tube was placed in an ice-water bath, the second test tube was left at room temperature, and the third test tube was placed in approximately 60°C of warm water. After filling the test tubes with three ml of the
Experiment #2: Investigating the Effect of Environmental pH on the Activity of Porcine Pancreatic Amylase
The practical was carried out to investigate the effect of pH on the reaction of the enzyme acid phosphatase.
Effect of pH on Enzyme Activity. 1. Dependent Variable. amount of product (glucose and fructose) produced 2. Independent Variable. pH 3. Controlled Variables. temperature; amount of substrate (sucrose) present; sucrase + sucrose incubation time
These results shown from this experiment led us to conclude that enzymes work best at certain pH rates. For this particular enzyme, pH 7 worked best. When compared to high levels of pH, the lower levels worked better. The wrong level of pH can denature enzymes; therefore finding the right level is essential. The independent variable was the amount of pH, and the dependent being the rate of oxygen. The results are reliable as they are reinforced by the fact that enzymes typically work best at neutral pH
= PH changes affect the structure of an enzyme molecule and therefore affect its ability to bind with its substrate molecules. Changes in pH affect the ionic bonds and hydrogen bonds that hold the enzyme together, which naturally affects the rate of reaction of the enzyme with the substrate. On top if this, the hydrogen ions neutralise the negative charges of the R groups in the
The results from the experiment determining the effects of pH on enzyme activity show that as the independent variable, pH, increases the dependent variable, percentage transmission, decreases. This is shown in the results as at the lowest pH, pH 4.0 the average percentage transmission is at its highest at 97%. At the highest pH, pH 8.0 the average transmission is 78.5%. This is also supported from the graph as it produces a negative gradient showing that as the percentage transmission will decrease with an increasing pH. This happens because the enzyme trypsin acts on the gelatine. Therefore as the pH increases towards the optimum pH more jelly will be broken down by the enzyme,
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.
The independent variable in this investigation is pH. Each individual enzyme has it’s own pH characteristic. This is because the hydrogen and ionic bonds between –NH2 and –COOH groups of the polypeptides that make up the enzyme, fix the exact arrangement of the active site of an enzyme. It is crucial to be aware of how even small changes in the
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.
Introduction: Enzymes are protein catalysts facilitating the conversion of substrates into products (Alexander and Peters, 2011). They go through a whole chemical reaction which starts off with the substrate and then ends up with a product. The only way this reaction can be adjusted or not even work is if they end up going through some sort of affect which only temperature and pH levels can do determining the environment. When enzymes are in an environment that is too acidic or alkaline, their chemical properties, sizes and shapes can become altered (Magher, 2015) Chemical modification of proteins is widely used as a too; to maintain a native conformation, improving stability (Rodriguez-Cabrera, Regalado, and Garcia-Almendarez, 2011) In this experiment, four trials were conducted and recorded every 15 seconds for 5 minutes in order to calculate the optimum levels and IRV.
An enzyme is a protein that acts as a catalyst which reduces the activation energy needed for a chemical reaction. Without the presence of enzyme, cell reactions would take so long that they would detectable. During a reaction, in the presence of an enzyme, the substrate first creates a complex with the enzyme. While the substrate is a part of the complex, it’s converted into the product. Then, finally, the complex dissociates from the molecule which allows the release of the enzyme and formed product. An enzyme’s activity depends on a variety of conditions which includes the pH level and temperatures. Phosphorylase is an enzyme that catalyze the addition of a