Assertion: Non-competitive inhibitor inhibits the catalyic activity of enzyme by binding with its active site.
Reasoning: Non-competitive inhibitor changes the shape of the active site in such a way that substrate can

Assertion (A) is not true but Reasoning (R) is correct.

The correct answer is 4. Assertion (A) is not true but Reasoning (R) is correct.

Assertion (A) is not true. Non-competitive inhibitors do not bind to the active site of the enzyme. Instead, they bind to a different site on the enzyme, called the allosteric site. The allosteric site is not involved in the catalysis of the reaction, but it can change the shape of the enzyme. When a non-competitive inhibitor binds to the allosteric site, it changes the shape of the active site so that the substrate can no longer bind.

Reasoning (R) is correct. Non-competitive inhibitors do change the shape of the active site in such a way that substrate cannot bind. This is how they inhibit the catalytic activity of the enzyme.