The enzyme acetylcholinesterase obeys Michaelis-Menten kinetics,with KM = 1.0 × 10-4M for its usual substrate acetylcholine. For a given quantity of enzyme [E]T and anacetylcholine concentration of .2M, the initial reaction rate isν = 43μM min-1. However, even at a much lower acetylcholine concentration of .02M, ν has the same value.
a. Using numerical calculations, show that this observation is reasonable.
b. At an acetylcholine concentration of 2.5×10-4M, what fraction of acetylcholinesterase has bound acetylcholine? Thatis, what is the ratio [ES] ? [E ]T
c. What would be a good range of [acetylcholine] for accuratelymeasuring KM ?