Final answer:
Km is equivalent to the dissociation constant of the ES complex at the point where the velocity of the enzymatic reaction is half of Vmax, which is V = Vmax/2 (option B).
Step-by-step explanation:
The question you've asked pertains to enzyme kinetics, specifically the circumstances under which the Michaelis constant (Km) can be considered equivalent to the dissociation constant of the enzyme-substrate (ES) complex. According to the Michaelis-Menten equation, Km is the substrate concentration at which the velocity (V) of the enzymatic reaction is half of its maximum velocity (Vmax).
Thus, Km becomes equivalent to the dissociation constant when the velocity is half the maximum velocity, or V = Vmax/2. This is because under these conditions, the rate at which the ES complex forms and the rate at which it dissociates are equal, leading to an equilibrium state where Km reflects both the formation and dissociation of ES.
Hence, the correct answer is Option B.