Chem 265
Laboratory Exercises 5
The enzyme cellobiase
Analysis Questions
1. Why is there no simple method to detect the formation of glucose or the disappearance of cellobiose?
2. Did you observe any changes in the enzyme reaction and control reaction tubes during the time that the reaction was occurring?
3. What happened to the solution in each cuvette after you added the enzyme/substrate mixture to the stop solution?
4. Compare the amount of product produced in the enzyme-catalyzed reaction againstthe control where no enzyme was added.
5. If you took a time point at 12 minutes, do you think more product would be produced than at 6 minutes? Explain.
6. Draw the plot of nanomoles of p-nitrophenol produced as a function of time. A hand-made sketch will not be accepted. This has to be a graph prepared using Excel or at least a graph done using graph paper(like for a math class) using a ruler, etc. Attach the graph to the lab report
7. Is the rate of product production constant over time? Hint: Is the slope of the line constant or does it change?
Justify your answer.
8. Describe the experiments that you would need to do to determine KM and vmax for cellobiase. Full credit will not be given to the answer “I will use a Lineweaver-Burke plot…”, aka, I need more details!
