Impact of Catechol Concentration on Catecholase Reaction Rate

When a chemical reaction to occurs a catalyst can be used to speed up the rate in which the reaction happens. Catalysts lower the activation energy needed for the reaction to take place. Catechol is the substrate in this experiment. Catecholase is the enzyme that “catalyzes the reaction of catechol and oxygen and is the enzyme that causes bruised or otherwise damaged fruit to turn brown” (“Enzyme Function”). This experiment can explain why fruits turn brown after a period of time.

In this study, catecholase, water, and different amounts of catechol were used.

This experiment would determine whether or not changing the amount of catechol in the catecholase and water solution would effect the rate of the reaction. The null hypothesis is the amount of catechol would have no effect on the rate of reaction into benzoquinone. The alternative hypothesis is the amount of catechol would have an effect on the rate of reaction into benzoquinone. The prediction stated that as the amount of catechol was increased, the rate of the reaction would increase until it became constant.

Data Collection

In the first stage of the lab, the spectrometer was calibrated using a blank that contained 500 microliters of catecholase and four milliliters of water.

Get quality help now

writer-Charlotte

Verified writer

Proficient in: Chemistry

4.7 (348)

“ Amazing as always, gave her a week to finish a big assignment and came through way ahead of time. ”

+84 relevant experts are online

Hire writer

After the spectrometer was calibrated three cuvettes, treatment A, with 1.5 milliliters of water, 2.5 milliliters of catechol, and 500 microliters of catecholase were prepared without cross contaminating the pipettes. Each one was recorded in the spectrometer and the spectrometer was recalibrated in between each replica. From the data recorded between 0-100 seconds, the mean concentration and mean absorbance were calculated.

T

he purpose of the three replicates was to check for any human errors or mistakes and look for alarming differences in the data. For the second stage of the lab the same process for the calibration was used. The blank and treatment A were tested with the same amounts as in the first stage; however, now treatment B with 2.75 milliliters of water, 1.25 milliliters of catechol, and 500 microliters of catecholase and treatment C with 3.375 milliliters of water, 0.625 milliliters of catechol, and 500 microliters of catecholase will be tested. Using the same process as for A, the data for treatment B and C were calculated. In this data, the amount of absorbance (ODU) was found for 0-100 seconds.

Data Analysis

Using the software “JMP”, the absorbance amounts were entered and the mean, standard deviation, p-value, and t-test were calculated. The mean is the average of all of the data points found and the standard deviation is “how far away from the mean the data points are spread” (Gregg et al., 2019). Based on the p-value that was found and the significance of that p-value, either the t-test is necessary or is not. The treatments were categorized by high, medium and low based on the amount of catechol in each treatment. Treatment A was high, treatment B was medium and treatment C was low. Two types of graphs were produced: a scatterplot graph with trend lines and a bar graph including standard errors at 100 seconds. ANOVA was run and the p-value was calculated based on the data at 100 seconds.

Results

The mean of the high treatment with 2.5 milliliters of catechol was 0.1064 and the standard deviation was 0.0737. The mean of the medium treatment with 1.25 milliliters of catechol was 0.1124 and the standard deviation was 0.0633. The mean of the low treatment with 0.625 milliliters of catechol was 0.1033 and the standard deviation was 0.0638. The average benzoquinone concentration (mM) at 100 seconds for the three different treatments (p=0.9). Because 0.9 is greater than the 0.5 significance level, there is no significance between the three treatments. Therefore, the null hypothesis was not rejected.