Noncompetitive (allosteric) inhibitor

Definition

A noncompetitive (allosteric) inhibitor binds to an enzyme at a site other than the active site, causing a conformational change that reduces the enzyme's activity. This type of inhibition is not overcome by increasing substrate concentration.

5 Must Know Facts For Your Next Test

1. Noncompetitive inhibitors bind to allosteric sites, not the active site.
2. This inhibition results in a conformational change in the enzyme structure.
3. The effect of noncompetitive inhibitors cannot be reversed by increasing substrate concentration.
4. They effectively decrease the maximum rate (Vmax) of enzymatic reactions without altering the affinity (Km) for substrates.
5. Noncompetitive inhibition plays a critical role in regulating metabolic pathways.

Review Questions

Related terms

Allosteric Site:

A specific site on an enzyme where a molecule can bind and alter enzyme activity.

Competitive Inhibitor: A molecule that competes with the substrate for binding to the active site of an enzyme.

Enzyme Kinetics:

The study of rates at which enzymatic reactions occur and how they are affected by changes in conditions and concentrations.