Active site

Definition

The active site is the region on an enzyme where substrate molecules bind and undergo a chemical reaction. It is typically a small pocket or groove on the enzyme's surface formed by amino acids.

5 Must Know Facts For Your Next Test

1. The active site's shape is complementary to the substrate, allowing for specific binding.
2. Enzyme-substrate specificity is often described by the 'lock and key' model or the 'induced fit' model.
3. Active sites can be affected by changes in temperature, pH, and the presence of inhibitors.
4. The binding of substrates to the active site lowers the activation energy required for a reaction.
5. Mutations in genes encoding enzymes can alter the structure of the active site, affecting enzyme activity.

Review Questions

• What role does the active site play in enzymatic reactions?
• How do temperature and pH affect the active site of an enzyme?
• Explain how substrate specificity is achieved at the enzyme's active site.

Related terms

enzyme:

A protein that acts as a biological catalyst to speed up chemical reactions without being consumed.

substrate:

The reactant molecule that binds to an enzyme's active site and undergoes a chemical transformation.

inhibitor:

A molecule that binds to an enzyme and decreases its activity, potentially affecting substrate binding at the active site.