1.9 Enzyme inhibition

Question 1

What is an enzyme inhibitor?

Answer 1

a substance that directly or indirectly interferes with the functioning of the active site of an enzyme and so reduces its activity.

Question 2

what are two types of enzyme inhibitor?

Answer 2

COMPETITIVE INHIBITORS- bind to the active site of an enzyme.
NON-COMPETITIVE INHIBITORS- bind to the enzyme at a position other than the active site.

Question 3

Describe a competitive inhibitor.

Answer 3

• their molecular shape is similar to the substrate, and so allows them to occupy the active site of an enzyme.
• it is not permanently bound to the active site, so when it leaves another inhibitor or a substrate can take its place.
• eventually, all substrate molecules will occupy an active site, but the higher the concentration of inhibitor, the longer this takes.

Question 4

Describe a non-competitive inhibitor.

Answer 4

• attaches to the enzyme at an alternate binding site, and alters the shape of the active site so substrate molecules can no longer occupy it and the enzyme doesn’t function.
• as it is not competing with the substrate, an increase in substrate does not decrease its effect.