Michaelis–Menten Inhibition
Distinguish inhibition mechanisms through their changes to apparent Km and Vmax.
Free theory articleDistinguish inhibition mechanisms through their changes to apparent Km and Vmax.
Concept & interpretation
Different types of enzyme inhibition affect the apparent Michaelis–Menten parameters, Km and Vmax, in distinct ways. By studying the initial-rate law v = S / (α + α'S) for normalized baseline parameters (Vmax = Km = Ki = 1), we can understand how competitive, uncompetitive, and pure noncompetitive inhibitors alter the saturation curve.
Explore the saturation curves
Open Michaelis–Menten Inhibition. The interactive model lets you change the Mechanism, Substrate, and Inhibitor concentrations.
- Set the Mechanism to "Competitive", Substrate to 1, and Inhibitor to 1. Observe that Apparent Vmax remains 1.0, while Apparent Km increases to 2.0.
- Change the Mechanism to "Noncompetitive". Notice that both Apparent Vmax and Apparent Km are affected. Apparent Vmax drops to 0.5, and Apparent Km remains 1.0.
- Change the Mechanism to "Uncompetitive". In this case, both Apparent Vmax and Apparent Km decrease to 0.5.
- Vary the Inhibitor concentration to see how the saturation curve shifts depending on the chosen mechanism. At I = 0, all mechanisms reduce to the standard Michaelis-Menten kinetics.