Enzyme Activity and Temperature

• October 12, 1999
• James Skemp
• article

I. Objective

For my lab report, I will be discussing the effect of temperature on enzyme activity. Enzymes help a chemical reaction occur faster. The ability of an enzyme to speed up a reaction depends on the environmental conditions. My hypothesis is that if the environment is very cold the enzyme will not be able to function very well. The reason that I say this, is because at cold temperatures, reactions tend to slow down.

II. Materials and Methods

For this experiment, I had; three test tubes A, B, and C and I had some enzyme extract (which was diced potato in sodium flouride (NaF) and is a crude extract of polyphenoloxidase). In all three test tubes, I added 20 drops of the enzyme extract. Next, I placed A in a 0°C ice bath, I placed B in a 20°C water bath and C in a 40°C water bath. The test tubes were then left in the bathes for 10 minutes. After 10 minutes, 20 drops of catechol was added to each test tube. They were then shaken, examined for color, and replaced in their bathes. Every five minutes, for twenty minutes, they were examined for color change and the results were recorded.

III. Results

Test tubes A, B, and C at 0, 5, 10, 15, and 20 minute times
Time	A- 0°C ice bath	B - 20°C water bath	C - 40°C water bath
0 Minutes	Light peach	Medium peach	Dark peach
5 Minutes	Light/medium peach	Medium/dark peach	Dark peach
10 Minutes	Medium peach	Dark peach	Dark peach
15 Minutes	Medium/dark peach	Dark peach	Dark peach
20 Minutes	Dark peach	Dark peach	Dark peach

Table 1: Color of the solution in test tubes A, B, and C at certain times and temperatures.

Figure 1: Enzyme activity against time. The more that the test tube solution color changes, then the enzyme activity is greater then the activity in one that does not change much. Tube A is at 0°C, tube B is at 20°C, and tube C is at 40°C.

IV. Discussion

At the end of the experiment, I found that each of the three test tubes ended up with the same color at the end of the experiment. Possible errors in this experiment are; adding unequal amounts of enzyme extract or catechol.

V. Conclusion

In this experiment, it took a longer time for tube A to get to the same point as tube C. Therefore, my conclusion based upon the experiment is that enzyme activity is greatest at 40°C and lowest at 0°C. Therefore, this enzyme works best at higher temperatures rather than lower ones.

Notes

Created: October 12th 1999
Modified: March 5th 2005
Notes: Report for a Principles of Biology I course during college, freshman year. Chart was created new, based upon the design of the old chart.