63 trate Dehydrogenase an Fazyme of the Citric Acid Cycdle Bettelheim/Landsberg, be Post-Lab Questions 1. In the procedure, for the the e preparation of the "cocktail" MgCl2 was added to the reaction mixture. What was the purpose of this reage be different from the result o nt? If this reagent was omitted, would the activity of the enzyme btained? If so, in what way? 2. Suppose that the collection of absorbance data was started after 100 sec. had elapsed. Would the calculated enzyme activity be (a) the same, (b) greater, or (c) smaller than if the experiment had been performed as directed in the procedure? Explain your answer. 3. What do your results show for the different enzyme concentrations used in this experiment? Is there an observable trend or do you get the same enzyme activity (units/mg powder)? 4. What kind of result would you expect if acid was introduced into the solution and the pÅI became 27 5. You ran two experiments with the same enzyme concentration in (1) and (2). Calculate the average ng powder. Does the reproducibility fall within +5%? Account for any large error.
A. Yes, hydrogen peroxide is only stable in the presence of catalase. Without it, store bought hydrogen peroxide decomposes quickly.
B. No, catalase sped up the rate of the reaction. Store bought hydrogen peroxide will decompose into water and oxygen gas much too slowly for visible bubbles to form.
C .No, hydrogen peroxide can only decompose into water and oxygen gas in the presence of catalase.
D. Yes, catalase had little effect on hydrogen peroxide decomposition. It would bubble quickly no matter what.
7. Do the optimal conditions for catalase functioning that you found correspond with the conditions in the mammalian liver where it came from?
A. Yes, catalase worked best at a neutral pH and temperature of 40 °C, both of which are close to mammalian tissue conditions.
B. No, catalase functions best at a much higher pH than in mammalian tissue and at a much lower temperature.
C. Yes, catalase functions best at the same low pH and temperature as occurs in the mammalian tissue.
D. No, catalase functions best at several very different pHs and temperatures, while the pH and temperature of mammalian tissue does not fluctuate.
8. How much slower would hydrogen peroxide likely be decomposed if catalase was not available in cells?
A. 100 times
B. 1,000 times
C. 10 times
D. 1,000,000 times
9. What are the enzyme, substrate, and product in these experiments?
10.What role does catalase play in the mammalian liver, or any other cell it is found in?