Effect of pH on the activity of salivary α amylase and determination of optimum pH for enzyme activity.
Kumar Swati
Department of Biotechnology and Bioinfomatics, DY Patil University, Navi Mumbai- 400614.
Abstract: Amylase is an enzyme that catalyses the breakdown of starch into simpler sugar molecules mainly maltose, glucose and dextrins. It acts by cleaving the α 1→4 glycosidic linkages between the amylose and amylopectin molecules of starch. The present study was conducted to study the effect of varying pH (3.0-9.0) on activity of α salivary amylase. The results obtained indicate that the optimum pH of the salivary amylase ranges between 6.0-7.0. The graph of enzyme activity v/s pH gave a bell shaped curve with the highest point on the curve indicating the optimum pH for the enzyme.
Keywords: amylase, activity, pH, optimum.
Introduction: An enzyme is a protein molecule considered to be a biological catalyst that helps in increasing the rate of a reaction. It is generally substrate specific and plays an important role in speeding up various biological reactions. (Guleria A and Chatana D.K., 2014). Enzymes activity is generally greatly affected by change in environmental conditions including change in pH, temperature etc. Enzymes work best at a certain pH or temperature known as the optimum and activity decreases below or above that point due to enzyme denaturation. (K. Amutha & K. Jayapriya, 2011). Hence determination of optimum reaction conditions of an enzyme
Amylase experiment # 2 was done to see how the pH affected the efficacy of the enzyme. First we collected all of the materials that were necessary to make this experiment. We needed five clean test tubes, the following standard solutions, 1% Starch Solution pH 3,1% Starch Solution pH 5,1% Starch Solution pH 7,1% Starch Solution pH 9,1% Starch Solution pH 11
Enzyme catalysis is dependant upon factors such as concentration of enzyme and substrate, temperature and pH. These factors determine the rate of reaction, and an increase in temperature or pH above the optimum will
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
How pH Affects the Break Down of Starch by the Enzyme Amylase Hypothesis: The optimum pH for the reaction of starch with amylase is pH 7. PH values lower or higher than this value will result in a slower rate of reaction. Amylase works in the range pH 3 to pH 11.
In this lab experiment the action of the enzyme Amylase was observed on starch (the substrate). Amylase changed the starch into a simpler form, the sugar maltose, which is soluble in water. Maltose then breaks down the glucose chains of starch in the pancreas and intestines. Amylase is present in human saliva, and begins to act on the starch in the food while still in the mouth. Exposure to heat or extreme PH (acid or base) will denature proteins. Enzymes, including amylase, are proteins; if denatured enzymes can no longer act as a catalyst for the reaction. In the presence of potassium iodide, starch turns a dark purple color; however maltose does not react with I2KI. The rate of fading of starch allows a quantitative measurement of reaction rate.
2. What effect did boiling and freezing have on enzyme activity? Why? How well did the results compare with your prediction?__Boiling caused amylase to be denatured, thus inactivating the enzyme. Freezing has no effect. The function of an enzyme is directly related to its environment, like temperature.__
test the pH of the amylase a drop of the solution should be put on pH
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 following experiments we will measure precise amounts of potato extract as well as Phenylthiourea, combined with or without deionized water and in some instances change the temperature and observe and record the reaction. We will also investigate the different levels of prepared pH on varying samples of the potato extract and the Phenylthiourea and record the results. We will answer question such as what is the best temperature for optimum temperature reaction as well as the best pH level for the same reaction.
Hypothesis: Differences in the pH will affect the rate of the velocity of the enzyme activity.
Amylase is an enzyme that is located in human saliva. It is solely accountable for breaking down starch as a way to start the breakdown of food and is one of the first steps of digestion. The time at which the enzyme starts the chemical reaction with starch is called the reaction rate. In order to study how amylase works against starch, this experiment consisted of two tests; each testing a different condition of amylase. The first test was to simply study the reaction between saliva and amylase and note the reaction rates. The second test was to see if increasing the pH would decrease the reaction rate or halt it all together. Saliva was collected, diluted, and tested for reactions between starch and amylase. Another sample of saliva was collected, diluted, and had its pH increased and tested for reaction rate. The findings after the experiment was conducted aligned with the original hypothesis. The change in pH did show a significant decrease in the reaction rate.
Different enzymes have different optimal pH levels. Changes in pH levels will affect the charge of the enzyme, hence affecting the enzyme’s shape and overall protein solubility. As the pH of the enzyme’s environment moves further from its optimal pH, enzyme activity diminishes. At the optimal pH level, an enzyme is functioning the best, in this case creates the fastest rate of enzyme activity. From the collected data, it can be seen that the hydrogen peroxide solution with pH 7 buffer has the largest slope, at 0.00153 kPa/s. This means that that for the enzyme catalase, the optimal pH level is pH 7. When the pH
The objective of the lab was to examine the effects of environmental variables on the functions of an enzyme. To the point, an experiment was conducted to test the effect of pH on the function of the enzyme Amylase.
In this lab our group observed the role of pancreatic amylase in the digestion of starch and the optimum temperature and pH that affects this enzyme. Enzymes are located inside of cells that increase the rate of a chemical reaction (Cooper, 2000). Most enzymes function in a narrow range of pH between 5 through 9 (Won-Park, Zipp, 2000). The temperature for which enzymes can function is limited as well ranging from 0 degrees Celsius (melting point) to 100 degrees Celsius (boiling point)(Won-Park, Zipp, 2000). When the temperature varies in range it can affect the enzyme either by affecting the constant of the reaction rate or by thermal denturization of the particular enzyme (Won-Park, Zipp, 2000). In this lab in particular the enzyme, which was of concern, was pancreatic amylase. This type of amylase comes from and is secreted from the pancreas to digest starch to break it down into a more simple form called maltose. Maltose is a disaccharide composed of two monosaccharides of glucose. The presence of glucose in our experiment can be identified by Benedicts solution, which shows that the reducing of sugars has taken place. If positive the solution will turn into a murky reddish color, where if it is negative it will stay clear in our reaction. We can also test if no reduction of sugars takes place by an iodine test. If starch is present the test will show a dark black color (Ophardt, 2003).