The Effect of low pH on Enzyme Activity

Design an experiment in which you will test the effect of an acidic fluid on enzymatic activity. (Recall: enzymes are proteins.) To complete this project, it may be useful for you to review the Scientific Method Tutorial (found the Course Content section of the classroom under the Science Learning Center link) and the Scientific Method lab (Lab 1), so that you can better understand how to design an experiment.  It may also be helpful for you to review your textbook and Lab 4 (Enzymes).  As you review Lab 4, you will be reminded that there are several factors that impact enzymatic activity: pH, temperature, and amount of reagent.  Feel free to refer to observations and information from Lab 4 as you complete the Final Applied Project (see the questions below). Or in other words, it is OK to use the same enzyme/substrate/method as you did in lab 4 (but modify the treatment), or you can search on-line to find a different enzyme/substrate/method for measuring enzyme activity.

As you design your experiment for this project, please remember that you are trying to examine how an acidic fluid will modify the outcome of an enzymatic reaction.  To successfully complete this project, you will need to identify the question(s) being asked in your experiment and the hypothesis that you are testing.  In your experimental design, you must clearly explain what you are doing. That means that you will need to identify the enzyme and the acid, as well as explain your experimental protocol (this information will help you to answer question 2).  You must also thoroughly explain how the addition of the acidic fluid impacted the overall reaction process (this information will help you to answer question 4).

Hint: Keep in mind that the acid will change the environmental conditions of the experiment (for example, a low pH value could change the shape of the active site on the enzyme protein), without directly participating in the reaction.

Lab Materials

You may need all or some of the following, depending on your experimental design:

Materials from your lab kit:

• pH paper
• hydrogen peroxide solution (you can purchase this at a pharmacy if you have used up the bottle that came with the lab kit)
• plastic beakers or cups
• vinegar
• yeast (can be purchased at grocery store if you need more)
• balloons
• plastic bottle
• marker for labeling of beakers

You may choose to use additional materials (different acidic solutions and/or different organisms and/or different substrate(s) if you chose to look at an enzyme other than catalase).

Outline (2%) submit in assignment folder.

I suggest you include the following in your outline:

• Name of enzyme you will use, and source (organism)
• The substrate
• How you will measure enzyme activity (method)
• What type of treatment you will you; type of solution(s), pH, length of exposure, how you will treat your samples
• The control(s) in the experiment
• Sample size
• Maybe how you plan to present your data (table and/or type of graph)
• Anything else you would like to get feedback on before you start your experiment.

Final Applied Lab Project: write a paper that includes the following:

1. Title page: title, your name, course name, semester

2. Introduction: introduce your project; include needed background information, the question(s) that you are asking and a clear hypothesis for your experiment.

3. Design an experiment. Provide a detailed account of the materials and methods used to conduct the experiment. Also include the methods for data collection and analysis.

4. Conduct the experiment and record your results. What did you observe? Present your data in table and/or graph. Remember to include the unit of measure.

5. Use your knowledge about enzymes and acids to interpret and discuss your results. It may be necessary for you to refer to your textbook and/or use other information resources. What effect does the acidic treatment have on the enzyme activity? Looking back, how could you have improved your experiment?

6. What is your conclusion? Was your hypothesis supported?

7. Cite all reference sources used (including text book) and provide a reference section with citations in APA format