Noncompetitive inhibition

Definition

Noncompetitive inhibition occurs when an inhibitor binds to an enzyme at a site other than the active site, causing a change in the enzyme's shape and reducing its activity. This type of inhibition cannot be overcome by increasing substrate concentration.

5 Must Know Facts For Your Next Test

1. Noncompetitive inhibitors bind to allosteric sites on the enzyme, not the active site.
2. The binding of a noncompetitive inhibitor changes the conformation of the enzyme, making it less effective or inactive.
3. Increasing substrate concentration does not affect the inhibition caused by noncompetitive inhibitors.
4. Noncompetitive inhibition decreases the maximum reaction rate (Vmax) but does not change the Km value.
5. Noncompetitive inhibitors can affect enzymes involved in crucial metabolic pathways, regulating their activity.

Review Questions

Related terms

Allosteric Site: A specific site on an enzyme other than the active site where molecules can bind and influence enzyme activity

Competitive Inhibition: A form of enzyme inhibition where an inhibitor competes with the substrate for binding at the active site

Km (Michaelis constant): A measure of an enzyme's affinity for its substrate; lower Km indicates higher affinity