What would happen to `V_("max")`, in presence of a competitive inhibitor ?

Options

A. Decreases
B. Increases
C. Remains the same
D. First increases then decreases

Answer

To determine what happens to \( V_{\text{max}} \) in the presence of a competitive inhibitor, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Competitive Inhibition**:
- In competitive inhibition, an inhibitor competes with the substrate for binding to the active site of the enzyme.

2. **Effect on \( V_{\text{max}} \)**:
- The presence of a competitive inhibitor does not change the maximum velocity (\( V_{\text{max}} \)) of the reaction. This is because if the concentration of the substrate is increased sufficiently, it can outcompete the inhibitor for the active site.

3. **Mechanism of Action**:
- At high substrate concentrations, the likelihood of substrate binding to the enzyme increases, effectively "swamping" the inhibitor. This means that the enzyme can still achieve its maximum reaction rate, as the inhibitor's effect can be overcome.

4. **Conclusion**:
- Therefore, in the presence of a competitive inhibitor, \( V_{\text{max}} \) remains the same.

### Final Answer:
- The \( V_{\text{max}} \) remains the same in the presence of a competitive inhibitor.