Which is not correct about competitive inhibition ?

Options

A. Inhibitor resembles the substrate in molecular structure
B. Competition occurs between substrate and inhibitor to bind
at active site
C. Binding of the inhibitor to active site decline the enzyme action
D. Inhibitor does not resemble the substrate in molecule structure

Answer

To determine which statement is not correct about competitive inhibition, we will analyze each statement one by one:

1. **Statement 1: Inhibitor resembles a substrate in molecular structure.**
- This statement is **correct**. In competitive inhibition, the inhibitor is similar in structure to the substrate, allowing it to compete for the active site of the enzyme.

2. **Statement 2: Competition occurs between substrate and inhibitor to bind at the active site.**
- This statement is also **correct**. In competitive inhibition, both the substrate and the inhibitor vie for the same active site on the enzyme. If the inhibitor binds, the substrate cannot, which inhibits the reaction.

3. **Statement 3: Binding of inhibitor to active site declines the enzyme action.**
- This statement is **correct** as well. When the inhibitor binds to the active site, it prevents the substrate from binding, thereby reducing or completely stopping the enzyme's activity.

4. **Statement 4: Inhibitor does not resemble the substrate in molecular structure.**
- This statement is **not correct**. As previously stated, in competitive inhibition, the inhibitor does resemble the substrate in its molecular structure, allowing it to compete effectively for the active site.

Based on the analysis, the statement that is not correct about competitive inhibition is **Statement 4**.