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 Vmax does not change, the Km changes. Km increases, indicating that the substrate has less affinity for the active site compared to the inhibitor.

Competitive inhibition

Uncompetitive Inhibition

In this type of inhibition, the inhibitor binds to the enzyme substrate (ES) complex. Vmax 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.

Enzyme concentration is depleted since some ES binds to I, preventing product formation
Uncompetitive inhibition

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 Vmax 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.

Noncompetitive inhibitor
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Courtney Simons
Courtney Simons
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Courtney Simons is a food science professor. He holds a BS degree in food science and a Ph.D. in cereal science from North Dakota State University.