Chapter 13, Problem 13P

Answers to all problems are at the end of this book. Detailed solutions are available in the Student Solutions Manual, Study Guide, and Problems Book.

Quantitative Relationships Between Rate Constants to Calculate K_m, Kinetic Efficiency (k_cat/K_m) and V_max - V Acetylcholinesterase catalyzes the hydrolysis of the neurotransmitter acetylcholine:

$\text{Acetylcholine}+{\text{H}}_{\text{2}}\text{O}\to \text{acetate+choline}$The K_m of acetylcholinesterase for its substrate acetylcholine is 9 × 10^-5 M. In a reaction mixture containing 5 nanomoles/mL of acetylcholinesterase and 130 μM acetylcholine, a velocity $v_0=40\mu \text{mol/mL}\cdot \text{sec}$was observed for the acetylcholinesterase reaction.

a. Calculate V_max for this amount of enzyme.

b. Calculate k_cat for acetylcholinesterase.

c. Calculate the catalytic efficiency (k_cat/K_m) for acetylcholinesterase.

d. Does acetylcholinesterase approach "catalytic perfection"?