Question

Blocking enzyme action by blocking its active sites is:

• A. Allosteric inhibition
• B. Feedback inhibition
• C. Competitive inhibition
• D. Non-competitive inhibition

Answer 1

The correct option is C Competitive inhibition

The process in which an inhibitor structurally resembles the substrate and inhibits the activity of the enzyme by competing with the substrate to bind to the active sites of the enzyme, is called competitive inhibition. Hence this is the correct answer.

Allosteric inhibition happens when the inhibitor binds to the enzyme at a site other than the active site of the enzyme (allosteric site) to inactivate the enzyme. This process alters the shape of the acitve site of the enzyme in such a way that the substrate can no longer bind to the enzyme.

Feedback inhibition is when excess product is formed such that it acts as an inhibitor and binds to an allosteric site to inactivate the enzyme so that no more product is formed.

Non-competitive inhibition is when an inhibitor binds to an allosteric site and inhibits the action of the enzyme. The inhibitor does not compete with the substrate for the binding and both can be bound to the enzyme at the same time.