18. All of the following statements are true about the relationships between [S], Km and Vmax EXCEPT:
a. As the [S] is increased, v approaches the limiting value, Vmax.
b. Km = Vmax/2.
c. The rate of the reaction, v, follows a first order rate equation
v = K'[A] and K' = Vmax/Km.
d. The rate of product formed, v, is at Vmax when [S] >> Km.
e. Km and Vmax assist in finding the rate of the enzyme catalyzed reaction only if the reaction is irreversible.