LABORATORY REPORT
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Activity: Name: Instructor: Date:
Enzyme Activity Pam Campbell Id 0002337 Dr. Murphy Nmezi August 9, 2011
Predictions
1. Sucrase will have the greatest activity at pH 6 2. Sucrase will have the greatest activity at 40 °C (104 °F) 3. Sucrase activity increases with increasing sucrose concentration until a plateau is reached.
Materials and Methods
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
Effect of Temperature on Enzyme Activity. 1.
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State the optimum pH for sucrase activity and how sucrase activity changes at more acidic and alkaline pH values. The optimum pH for sucrase activity is 6 and decrease with greater acidic and alkalline values.
Table 2: Effect of Temperature on Sucrase Activity
10 °C (50 °F) 0.006 0.006 0.007 0.006 20 °C (68 °F) 0.251 0.285 0.273 0.27 30 °C (86 °F) 0.767 0.789 0.799 0.785 Optical Density 40 °C 50 °C (104 °F) (122 °F) 0.969 0.93 0.947 0.922 0.945 0.947 0.954 0.933 60 °C (140 °F) 0.843 0.827 0.829 0.833 70 °C (158 °F) 0.641 0.623 0.632 0.632
1 2 3 average
Effect of Temperature on Sucrase Activity
2. State the optimum temperature for sucrase activity and how sucrase activity changes at lower and higher temperatures. The optimum temperature for sucrase activity is 40 degrees Celcius. Sucrase activity decrease at greater or lower temperature and may become denatured.
Table 3: Effect of Sucrose Concentration on Sucrase Activity
1 2 3 average 35 g/L 0.988 1.001 0.987 0.992 30 g/L 0.983 0.977 1.012 0.991 25 g/L 0.946 0.94 0.943 0.943 Optical Density 20 g/L 15 g/L 0.93 0.861 0.922 0.86 0.908 0.848 0.92 0.856 10 g/L 0.779 0.759 0.774 0.771 5 g/L 0.513 0.523 0.506 0.514 0 g/L 0.003 0.002 0.002 0.002
Effect of Sucrose Concentration on Sucrase Activity
3. State how sucrase activity changes with increasing sucrose concentration. Sucrase
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
at that temperature, there was the most amount of catalase activity. On the pH graph, the
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
The temperature can have a major impact on an enzyme. According to Campbell Biology author Reece etc. 2011 “The enzyme reaction will increase as the temperature increase with the increasing temperature….substrates collide with active sites more frequently when the molecules move rapidly.”(Reece etc 2011) Every enzyme hits its optimal temperature the reaction will be at its highest point.(Reece etc. 2011) When the
Students will be observing normal catalase reaction, the effect of temperature on enzyme activity, and the effect of pH on enzyme activity in this experiment. The enzymes will all around perform better when exposed in room temperature than when it is exposed to hot and cold temperatures. This is based on the fact that the higher the temperature, the better the enzymes will perform, but as the temperature reaches a certain high degree, the enzymes will start to denature, or lose their function.
Given the background, we hypothesized that for the first experiment, the lactase will break down lactose in milk and have a similar effect to sucrose. We also predicted that the Milk + Lactase reactant would have more glucose, the Milk + Water reactant would have a little bit of glucose broken down, the Sucrose + Lactase reactant would have less glucose than the Milk + Water reactant, and the Sucrose + Water reactant would have little to no glucose at all. As for the first procedure of the second experiment, we had hypothesized the more basic the solution would become, then the more glucose there would be. Our prediction for the first procedure of the second experiment was that there would be no glucose found in the solutions containing pH 4 and pH 7. For the second procedure of the second experiment, our hypothesis was that glucose would be present in the reactants at 4ºC and 25ºC while the reactant that had been in the hot water bath at 100ºC would have little to no glucose because it would have evaporated. We predicted that for this temperature experiment, the glucose would evaporate at 100ºC and would remain at 4ºC and 25ºC. For the first experiment we had found that a reactant of Milk + Lactase have high levels of glucose, while the other three reactants do not. As for the second experiment, for the first procedure, amounts of glucose were found in
Therefore the optimum temperature for sucrase is 37 degrees Celsius, the optimum pH is 2.0, and the optimum concentration is 10%.
I predict that at temperatures above 70°C the enzyme lipase will become denatured and at temperatures below 10°C the enzyme will become inactive. Since lipase operates within the human body I’d also predict that its optimum temperature would be around human body temperature which is approximately 37°C. I predict that before the optimum temperature the rates will gradually increase and preceding the optimum there will be a drastic decrease in rate until the enzyme is denatured.
If different temperatures are used to catalyze enzyme activity, then the lowest temperature would produce the quickest reaction rate because enzymes can become denaturized at higher temperatures
If temperature of the water(enzyme environment) is increased to 35°C, then the enzyme activity will
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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.
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.
We did this to test which test tube would contain the highest concentration of glucose. What we wanted to know was if the lactase would affect the function of the enzyme. Our hypothesis is the lactase functions within a narrow pH and that will change in pH would affect the function of the enzyme. We predict that if we change the environmental factors it will have an effect the function of the enzyme if the pH is outside the range in its optimum activity. Our hypothesis was then proven because the reaction only occurred in a neutral and acidic state of pH, not basic. Which means the enzymes prime ability to function is a neutral, and acidic pH range.