Which of the following remains unchanged in reversible competitive inhibition?

Options

A. `V_("max")`
B. `K_(m)`
C. Both
D. None of these

Answer

To solve the question regarding reversible competitive inhibition, we need to understand the effects of this type of inhibition on enzyme kinetics, specifically focusing on two key parameters: Vmax and Km.

### Step-by-Step Solution:

1. **Understanding Competitive Inhibition**:
- In competitive inhibition, an inhibitor competes with the substrate for binding to the active site of the enzyme. This means that the presence of the inhibitor can reduce the rate of reaction when the substrate concentration is low.

2. **Effect on Vmax**:
- Vmax is the maximum rate of reaction when the enzyme is saturated with substrate. In competitive inhibition, as the substrate concentration increases, it can outcompete the inhibitor for binding to the enzyme. Therefore, at very high substrate concentrations, the effect of the inhibitor can be overcome, and Vmax remains unchanged.

3. **Effect on Km**:
- Km is the Michaelis constant, which represents the substrate concentration at which the reaction rate is half of Vmax. In competitive inhibition, the presence of the inhibitor increases the apparent Km value because a higher concentration of substrate is needed to achieve the same reaction rate. Thus, Km increases in competitive inhibition.

4. **Conclusion**:
- Since Vmax does not change and Km increases in reversible competitive inhibition, the correct answer to the question "Which of the following remains unchanged in reversible competitive inhibition?" is **Vmax**.

### Final Answer:
- The correct option is **Vmax**.

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