Potato Enzyme Lab Report

The purpose of the lab was to determine the enzymatic activity of PPO as previously stated we had to establish the relationship between dopachrome concentration and its absorbance which is shown in figure 1. After charting the relationship a polyphenol oxidase test was done to see if any change had occurred including if a color was present in the different variations of dopa, buffer, and PPO extract which can be seen in table 1. Table 2 shows the enzyme assay reaction tubes indicating the final amount of dopa. Table 3 indicates the absorbance data gathered in the experiment. The odd number tubes were the control and the even was experimental. The control tubes had a buffer in them while the even ones did not instead they got 0.5 mL of dopa

In table 5 the concentration values of Dopachrome was derived from the standard curve graph in figure 1. Then the concentrations were converted to millimoles as seen in table six. Table six can be related to figure 2 as the concentrations were graphed in accordance with time and figure 2 expresses that as the initial velocity of the enzyme reactions at different dilutions relative to the 1X stock. Overall the activity of the potato as found in Table 7 was calculated by multiplying the initial velocity by the volume of the enzyme to get the activity of the diluted sample and from there one can multiply by the dilution factor to find the activity sample of just the potato. Table eight describes the calculations needed to be done to prepare for the enzymes to make sure the dilution factors were right. The kinetics of the enzyme concentrations can be clearly seen in the last figure, figure 3, the dilutions steep slopes correlate to how concentrated the solutions were and how fast reactions took place. Lastly, the activity per weight of the potato was found by converting mmol/min/mL to

As indicated in figure 1 I obtained an R2 value of 0.9993 which is very close to 1, the closer to the value of 1 the more accurate your data is. Part two of the lab deals with actually measuring enzyme activity of the PPO as it interacts with dopa. The Qualitative PPO test, table 1, show that when PPO and dopa reaction it can change the color of a solution from clear to orange because of the resulting dopachrome formation. Table three records the absorbance of control and experimental tubes the control tubes were unsurprisingly consistent in there absorbances, but the experimental tubes increased in absorbance for the reaction over time meaning more dopachrome was created. Since absorbance and concentration are directly related as one increases the other increases which were documented in table 5. At the end we gathered that the average activity of the potato was 0.0430 (mmole/min)/mL and the activity per weight of potato was 1.147e^-5 which re some pretty small numbers as said previously if we make these numbers smaller or even zero we would have a longer shelf life for produce which can help spread them around the