Impact of Temperature on Catalase’s Function in Catalysis of Hydrogen Peroxide NAVYA NARUKULLA 10
Impact of Temperature on Catalase’s Function in Catalysis of Hydrogen Peroxide
NAVYA NARUKULLA
10.22.2018
SBI 3U9
Ms. Zamora
TESTABLE QUESTION
How does temperature play a role on the catalase enzyme’s efficiency to catabolize hydrogen peroxide(H2O2)?
Independent Variable: temperature
Dependent Variable: height of bubbles formed
Constants: type of enzyme (catalase), the volume of H2O2 (3 mL), the mass of potato slices (29g), duration of the experiment (3 minutes)
HYPOTHESIS
As the temperature of the enzyme active site increases, the efficiency to catalyze hydrogen peroxide which is determined by the height of the bubbles formed also increases.
DATA TABLE
Figure 1: Qualitative and Quantitative Observations of Reactions
Height of Bubbles Formed (cm)
Temperature (Celcius)
Qualitative Observations
Trial 1
Trial 2
Trial 3
Total Average
10°C
– very slow fizzing
– potato slice floats up after sinking
– small bubbles emerge from potato
0.2cm
0.3cm
0.3cm
0.23cm
21°C
– slight fizzing
– bubbles immediately rise from potato
– potato floated up from the bottom of the tube as soon it was placed in the substrate
0.4cm
0.4cm
0.5cm
0.43cm
40°C
– intense fizzing
– potato floated up from the bottom of the tube as soon it was placed in the substrate
– bubbles rise faster from potato
0.6cm
0.7cm
0.7cm
0.67cm
DISCUSSION/ANALYSIS
With the experimental objective being to determine the impact various conditions have on the function of catalase. This lab reached the objective by determining the impact temperature has on the function of catalase. Through the results acquired, it is evident how temperature plays a major role in catalase’s activity. The vast difference in the quantitative results between the minimum and maximum temperatures tested displays how temperature change in the active site could cause changes in catalysis of the substrate. Between 10°C and 40°C, the height of the bubbles increased by 0.44cm on average.
The results obtained matched the expected results as the increase in temperature was in correlation with the increase in efficiency of catalysis which was determined by the height of the bubbles formed during the reaction. From the results gathered enzyme activity increases when the temperature does as well. At the lowest temperature tested of 10°C, the substrate and enzyme molecules lacked kinetic energy for collisions and hence the efficiency of catalysis was lower, creating bubbles only 0.23cm in size on average. The time taken for the bubbles to start forming was also longer which shows how it takes longer to reach the transition state when there is low kinetic energy caused by the temperature. At room temperature (21°C), the average size of the bubbles was 0.43cm which is almost the halfway point to the optimum point. At 40°C, the average size of the bubbles was 0.67cm meaning the substrate and enzyme molecules excelled in kinetic energy with a lot of motion and collisions increasing the efficiency of catalysis.
As regards to our observations, it is evident that the colourless gas bubbles formed are oxygen which is one of the products, the other being water (H2O). The reason the potato sank to the of the tube was due to its density being higher than water. It can be assumed that the release of oxygen gas bubbles from the potato produced an upthrust to push the potato upwards to the surface of the substrate and hence the potato temporally floats on the surface. The speed of the potato floating up is in correlation to the efficiency of catalase. The more bubbles created, the faster the potato floated up to the surface.
Theoretically, according to Smith Brett, the optimum temperature of catalase is 37°C which means in the 40°C trials, the catalase surpassed the optimum point and began to denature. The rate of catalysis is supposed to decrease once the optimum temperature has been overcome which matches our results as well because 40°C was right after 37°C. The height of the bubbles once the denaturing began was on average 0.67cm. It can be predicted that the height of the bubbles at the optimum point was somewhere between 0.7cm to 0.8cm. The optimum point is the temperature at which the enzyme is 100% active and is working at its maximum capacity. The image displayed above can be used to predict the temperature at which the catalase would be completely denatured preventing any catalysis which would be around 60°C.
To achieve results with greater accuracy, multiple trials with the same temperature have been performed to minimize and identify errors if there were any. The mass of each of the potato slices was also measured to be equal throughout all the trials to prevent any changes in the efficiency of catalysis. The time of the experiment also remained constant throughout all the trials. Lastly, test tubes with H2O2 were put into the water baths for a few minutes before adding potatoes and this allowed the temperature of the content to reach that of the water baths. The final results in each trial were close to one another meaning there weren’t any major errors between trials.
The sources of error of in our experiment may have been placing the potato slices in the H2O2 at different times. Although the difference between each trial may have been in only seconds, the results may have varied as some substrates were exposed to the enzyme a few seconds more or less than the intended experiment duration of 3 minutes. This error may have slightly altered the results of the efficiency of catalysis. This inaccuracy could have been improved through doing each trial individually. Although the mass of all the potatoes was equal, they varied in surface area. The surface area could have played a role in catalysis because some slices could have had more activity since more of the enzyme was exposed to the substrate. This error could have been avoided if each of the slices was measured and cut according to a specific size and mass.
Limitations: time, strength: temp remained constant
If this experiment were to be done again, inhibitors of catalase in different concentrations would have been added to the substrate to identify how inhibitors play a role in the efficiency in catalysis of H2O2. Example of inhibitors of catalase would be copper(II) sulfate and potassium cyanide. We would have also recorded qualitative observations for each trial to determine any changes present in each trial.
CONCLUSION
In conclusion, the enzyme catalase exhibits low activity at low temperatures (10°C) and high activity at higher temperatures (40°C) which substantiates the hypothesis as accurate. The experimental set-up was generally satisfactory to minimize errors except for some defects such as the methodology in measuring the surface are of potatoes and the duration of the experiment for each trial.
References
Smith, Brett. (2018, April 30). How Does Temperature Affect Catalase Enzyme Activity? Sciencing. Retrieved from https://sciencing.com/temperature-affect-catalase-enzyme-activity-7776025.htm
Sevag, M. G., and Maiweg, Lore, Naturwissenschaften, 22, 561; 1934.
