Question

What is competitive inhibition. Give an example.

Answer 1

Hint: It is a reversible process in the majority of the cases. It has its major function in the production of pharmaceuticals. It is even seen in normal biological processes in nature.

Complete answer:
Competitive inhibition is a process when a chemical substance abrupts an ongoing chemical reaction by inhibiting the effect of another by bonding or binding. When an inhibitor binds with the target molecule, it competes with the natural substrate of the reaction. It blocks the binding site of the substrate causing a stop to the normal reaction. However this can be controlled by increasing the amount of substrate which increases the possibility of the substrate to bind instead of the inhibitor.
In the majority of the cases the binding of the inhibitor to the target site is a reversible process.
The inhibitor resembles the substrate to properly bond with the target site. In competitive inhibition both the substrate and inhibitor compete with one another to bind on the active enzyme site. This site is the target site which will allow only one of them to bind onto its surface.
This process is commonly used in the pharmaceutical branch.
Example—
A chemotherapy drug, methotrexate is a competitive inhibitor. It is similar to an enzyme folate. It has a similar structure. Folate binds to enzyme dihydrofolate reductase for the synthesis of DNA and RNA. When methotrexate binds instead it abrupts the reaction making it inactive which does not allow any further growth of the cancerous cells.

Note: When an inhibitor binds with the target molecule, it competes with the natural substrate of the reaction. It blocks the binding site of the substrate causing a stop to the normal reaction. However this can be controlled by increasing the amount of substrate.