Michaelis-Menten plots can be used to identify the type of enzyme inhibition that is present. As you should remember, there are three main types of enzyme inhibition i.e., competitive, uncompetitive and noncompetitive.

Competitive Inhibition

In competitive inhibition, the inhibitor can be overcome by increasing the substrate concentration. Hence maximum velocity is reached. However, notice that while the V_max does not change, the Km changes. Km increases, indicating that the substrate has less affinity for the active site compared to the inhibitor.

Uncompetitive Inhibition

In this type of inhibition, the inhibitor binds to the enzyme substrate (ES) complex. V_max cannot be reached since the concentration of the enzyme is decreased. The Km is less due to tighter binding of substrate within the ESI complex.

Noncompetitive inhibition

In this type of inhibition, the inhibitor binds to both the enzyme and the ES complex, with no preference for either. Again, the V_max cannot be reached since the concentration of the enzyme is decreased. However the Km (affinity of substrate to enzyme) does not change since the substrate have the same affinity for the enzyme regardless of whether only E is present or EI.

Courtney Simons

Administrator

Dr. Simons is a food science educator. He earned his bachelor’s degree in food science, and Ph.D. in cereal science at North Dakota State University.