Which of the following is required for enzyme action ?

Options

A. Low `K_(m)` value
B. High `K_(m)` value
C. Low ki value
D. High Ki value

Answer

To determine which of the following is required for enzyme action, we need to analyze the given options in relation to enzyme kinetics:

1. **Understanding Km and Ki**:
- **Km (Michaelis constant)**: This value indicates the substrate concentration at which half of the enzyme's active sites are occupied. A low Km value suggests a high affinity between the enzyme and the substrate, meaning that the enzyme can effectively catalyze the reaction even at lower substrate concentrations.
- **Ki (Inhibition constant)**: This value indicates the potency of an inhibitor. A low Ki value means that the inhibitor binds tightly to the enzyme, which can slow down the reaction rate. Conversely, a high Ki value indicates that a larger amount of inhibitor is needed to affect the enzyme's activity.

2. **Analyzing the Options**:
- **Low Km Value**: This is favorable for enzyme action as it indicates a high affinity for the substrate.
- **High Km Value**: This would indicate a lower affinity for the substrate, which is not ideal for enzyme action.
- **Low Ki Value**: This means that the inhibitor binds tightly to the enzyme, which can hinder enzyme action.
- **High Ki Value**: This means that a larger amount of inhibitor is required, which is also not conducive to enzyme action.

3. **Conclusion**:
- The best option for facilitating enzyme action is a **low Km value**, as it indicates a strong affinity for the substrate. Therefore, the correct answer to the question is **Low Km Value**.

### Final Answer:
**Low Km Value** is required for enzyme action.