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Effect of enzyme concentration on enzyme kinetics
Factors governing the Rate of Enzyme Reactions
Enzyme kinetic abstract
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The hypothesis is supported by the experiment in that with increased starch concentration, the amylase activity increased each time and the salivary amylase functioned best at higher concentrations of starch. Also, for the most part, the reaction followed the general trend of how at lower concentrations, the increase in reaction rate is greater, while at higher concentrations, the increase in reaction rate is less. Despite some discrepancies in trend, specifically at the 40g/L concentration, figure 1 still displays how the amylase activity eventually reaches a plateau, as mentioned in the hypothesis. From the results it appears that the point of saturation for this reaction is at the concentration 50g/L as the amylase activity rates for 50g/L …show more content…
and 60g/L are almost the same (0.244g/min and 0.245g/min). From this it can be taken that just as mentioned in the hypothesis, the reaction rate plateaus due to all active sites being blocked or occupied. Evaluation and Improvement Methods Overall, the experiment showed consistent results for the trials carried out at each concentration as most trials gave identical results.
However, there were a few trials that showed slightly different results. The reason for this could be that since this experiment is one pertaining to colour change, the change in colour may not be clear at times, making the end point difficult to discern. One reason for inconsistent colour change could be that though two drops of iodine were used each time to test the colour change, the dropper is not precise and does not have an exact gauge of how many millilitres are being used each time, affecting the uniformity of each iodine test. Also, since the amylase-starch solution was extracted manually using a dropper, there could have been inaccuracy in adding the solution to the iodine at exactly the same time for each trial. Though the plotted points did generally, follow the trend of how at lower concentrations the change in reaction rate is greater than at higher concentrations, the points are not exact and the line is not as curved or smooth as expected. This could be because of the 30 second interval used between each iodine test as the amylase probably does not react in exact, 30 second intervals. The point of saturation could have been reached any time between the 30 seconds, for example at 15 seconds, but this would not have been able to be
known. Although the final point of saturation was able to be found, there are steps that could have been taken to increase the accuracy of the results. One would be pertaining to the generalization due to the 30 second interval used. Instead of using a 30 second time interval, a shorter time of 10 seconds could be used to find out more accurate results for the total time it takes for the starch to be digested. Though for most concentrations, consistent reaction times were able to be obtained, there were a couple concentrations where the reaction times were not uniform. For these concentrations, more trials could have been done to increase the accuracy of results. Another improvement that could be implemented for this experiment that could expand the ideas studied, is to
To begin the study, I first calculated how much of each solution I would need. I knew that the final volume of my reaction solution needed to me 30ml, so I calculated how much of starch, amylase, and tris buffer I would need. I used the formula Concentration (initial stock solution) x Volume (initial stock solution)= Concentration (final solution) x Volume (final solution). Using this formula, I found that I would need an initial concentration of 21 ml of starch, 1 ml of amylase, and 8 ml of the tris buffer. After calculating the amounts of substances I would need, I created two different solutions, one with the Carb Cutter and one without. Carb Cutter claims to block starch, however, to find this I needed to test the absorbance level of the control to compare the effect Carb Cutter had on the solution. Below is a graph showing the concentration of the control reaction over one minute intervals through the
In both solutions of catalase there is a steady increase in reaction relative to the hydrogen peroxide concentration as it increases. A significant jump is observed in the carrot catalase solution between .25% and .5% whereas the pinto bean catalase solution has a steady increase. Each solution doesn’t generate much more reaction to the next increment of hydrogen peroxide concentration, 1%. In general it stayed level. This continued to be a trend for the pinto bean catalase solution, plateauing through to the 6% concentration of hydrogen peroxide. This is known as the point of saturation.
Iodine turns into a blue/black color when in the presence of starch, after using iodine if the blue/black color is absent then the starch has been used usually making a halo around the inoculum, resulting in a positive result. If it stays blue/black then the starch is still present meaning the organism cannot produce amylase causing a negative result. My color stayed blue/black and there was no evidence of a halo, meaning my organism is negative for producing amylase. (handout, amylase)
called an active site. This active site is made by a few of the amino
Finally, the last part of the experiment examined the enzyme activity at different pH levels. Four sets of 11 tubes were set up in this part. The procedure for this part is the same as before, but 4 other buffers were substituted for the standard pH 7.3 phosphate buffer. Set A used the 5.5 pH buffer while set B used the 6.5 pH buffer. The buffer of pH 8.5 was used for set B and for set D the pH was 9. The absorbance readings for 4 sets were taken and recorded in table 13. Using the linear equation that the best-fit line gave for each set, the Km and the Vmax of each set were determined. Then, table 15 was made by dividing the Vmax by the Km. of the four pHs. The Vmax and Km of the control set were also used to make
In this investigation, the concentration of enzyme will be inversely proportional to the time taken for starch to be digested, until at a certain point where it will level out. It will level out because, all the substrates would have been used up, therefore there will be no more substrates for the enzymes to work on. In effect, the concentration of the substrate will act as a limiting factor. However, enzyme concentration will be directly proportional to the rate of reaction.
I blanked it with 2 cm³ water, 1 cm³ amylase and 3 drops of iodine.
In this experiment as a whole, there were three individual experiments conducted, each with an individualized hypothesis. For the effect of temperature on enzyme activity, catalase activity will be decreased when catalase is exposed to temperatures greater than or less approximately 23 degrees Celsius. For the effect of enzyme concentration on enzyme activity, a concentration of greater or less than approximately 50% enzymes, the less active catalase will be. Lastly, the more the pH buffer deviates from a basic pH of 7, the less active catalase will be.
According to the graph on amylase activity at various enzyme concentration (graph 1), the increase of enzyme dilution results in a slower decrease of amylose percentage. Looking at the graph, the amylose percentage decreases at a fast rate with the undiluted enzyme. However, the enzyme dilution with a concentration of 1:3 decreased at a slow rate over time. Additionally, the higher the enzyme dilution, the higher the amylose percentage. For example, in the graph it can be seen that the enzyme dilution with a 1:9 concentration increased over time. However, there is a drastic increase after four minutes, but this is most likely a result of the error that was encountered during the experiment. The undiluted enzyme and the enzyme dilution had a low amylose percentage because there was high enzyme activity. Also, there was an increase in amylose percentage with the enzyme dilution with a 1: 9 concentrations because there was low enzyme activity.
3. The higher the concentration of the enzyme the more there are to catalyze the reaction. Taking information from graph 1 (change in mL of enzyme), the more mL of enzymes that there are the faster the reaction rate is. It would increase until there was no substrate left available for a reaction.
Investigating the Effect of Enzyme Concentration on the Hydrolysis of Starch with Amylase Aim: Investigate the effect of enzyme concentration on the rate of an enzyme-controlled reaction. Using amylase and starch as my example. Introduction: I am investigating the effect of the concentration of the enzyme, amylase on the time taken for the enzyme to fully breakdown the substrate, starch to a sugar solution. The varied variable will be the concentration and all other variables are going to be fixed. The different concentrations will be: 0.5% 0.75% 1.0% 1.5% 2% An enzyme is a class of protein, which acts as a biological catalyst to speed up the rate of reaction with its substrates.
...eadings. The absorbance readings for test tube 5, were always further away from the expected values than test tube 1. This is because the NaOH was not added to each tube at a time, but in sequential order with the test tube numbers. This allowed the reaction in test tube 5 to proceed longer than in test tube 1, allowing more product to be produced, giving a higher absorbance reading than expected. In fact, this trend was shown in all the test tubes. In increasing order of test tube numbers, every absorbance was more off than expected.
and a fall in temperature will slow them down. In many cases a rise in
However, in order to measure the rates of reaction, sodium thiosulphate and starch are added. Sodium thiosulphate is added to react with a certain amount of iodine as it is made. Without the thiosulphate, the solution would turn blue/black immediately, due to the iodine and starch. The thiosulphate ions allow the rate of reaction to be determined by delaying the reaction so that it is practical to measure the time it takes for the iodine to react with the thiosulphate. After the all the thiosulphate has reacted with the iodine, the free iodine displays a dark blue/black colour with the starch. If t is the time for the blue/black colour to appear, then 1/t is a measure of the initial rate.
From the Results there is an anomaly which is with the test tubes at 58oC, the results spike from 0.100 to 0.536 and then back down to 0.302, this anomaly may have happened due to the three samples in the test tubes potentially having a higher level pigment in the vacuole than the other