Malonate functions as substrate analogue and inhibits enzyme

Options

A. Succinate dehydrogenase
B. Pyruvate oxidase
C. Fumarase
D. Isocitrate dehydrogenase.

Answer

**Step-by-Step Solution:**

1. **Understanding the Concept of Substrate Analogs:**
- A substrate analog is a molecule that resembles the substrate of an enzyme and can compete with it for the active site. This competition can inhibit the enzyme's activity.

2. **Identifying the Role of Malonate:**
- Malonate is recognized as a substrate analog. It competes with the actual substrate (succinate) for binding to the active site of the enzyme.

3. **Mechanism of Competitive Inhibition:**
- When malonate binds to the active site of the enzyme (succinate dehydrogenase), it prevents the actual substrate (succinate) from binding. This leads to a decrease in the enzyme's activity, which is characteristic of competitive inhibition.

4. **Identifying the Target Enzyme:**
- The specific enzyme that malonate inhibits is succinate dehydrogenase. This enzyme is responsible for the oxidation of succinate to fumarate in the mitochondrial inner membrane.

5. **Conclusion:**
- Therefore, malonate functions as a substrate analog and inhibits the enzyme succinate dehydrogenase.

**Final Answer:**
Malonate functions as a substrate analog and inhibits the enzyme succinate dehydrogenase.

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