Competitive inhibitor

Definition

A competitive inhibitor is a molecule that binds to the active site of an enzyme, preventing the substrate from binding and thus inhibiting enzyme activity. This type of inhibition can be overcome by increasing the concentration of the substrate.

5 Must Know Facts For Your Next Test

1. Competitive inhibitors resemble the enzyme's normal substrate.
2. They bind reversibly to the active site of an enzyme.
3. The effect of a competitive inhibitor can be reduced by increasing substrate concentration.
4. Competitive inhibition increases the apparent Km (Michaelis constant) without affecting Vmax (maximum velocity).
5. Enzymes with competitive inhibitors require higher substrate concentrations to reach half their maximum reaction rate.

Review Questions

Related terms

Non-competitive Inhibitor: A molecule that binds to an enzyme at a location other than the active site and reduces its activity.

Active Site:

The specific region of an enzyme where substrate molecules bind and undergo a chemical reaction.

Allosteric Site:

A site on an enzyme, separate from the active site, where molecules can bind and affect enzyme activity.