BCH 361 Advanced Biochemistry I Fall 2020
Group Discussion Questions
Week 2 (September 14/15)
1. PowerPoint slides 24/25: mechanism of acetylcholinesterase. What types of catalysis do you
observe? What evidence is there in the mechanism to back up your conclusions?
2. PowerPoint slide 30: pH-rate profile for acetylcholinesterase. What does the shape and positioning
of the curve tell you about the enzyme? Back up your decision with evidence from the plot.
3. How do enzymes enhance the rate of chemical reactions?
4. What is the structural basis for enzyme specificity?
5. What would be the result of an enzyme having greater binding energy for the substrate than for the
6. Why does the activation energy not appear in the ΔG of a reaction?
7. Consider the following reaction:
After the reactants and products were mixed and allowed to reach equilibrium at 25°C, the
concentration of each was measured:
Equilibrium concentration (M)
a. Calculate Keq and ΔG°’
b. If you had a solution of 0.1M glucose-6-phosphate and added to it phosphoglucomutase, what
will be the final concentrations of glucose-1-phosphate and glucose-6-phosphate?
8. The isomerization of dihydroxyacetone phosphate (DHAP) to glyceraldehyde-3-phosphate (GAP) has
an equilibrium constant of 0.0475 under standard biochemical conditions. Calculate ΔG°’ for the
isomerization. Then, calculate ΔG for this reaction when the initial concentrations of DHAP and GAP
are 2 x 10-4 and 3 x 10-6, respectively. What do these values tell you about the importance of ΔG
compared with that of ΔG°’ in understanding the thermodynamics of intracellular reactions.
9. Trivia Question (time permitting): when was the 7th class of enzymes added to the EC numbers?