A competitive inhibitor of succinic dehydrogenase is

Options

A. Malate
B. Malonate
C. Oxaloacetate
D. `alpha`-ketoglutarate

Answer

**Step-by-Step Solution:**

1. **Understanding Competitive Inhibition**:
- Competitive inhibition occurs when an inhibitor molecule competes with the substrate for binding to the active site of an enzyme. This means that the inhibitor can block the substrate from binding, thereby inhibiting the enzyme's activity.

2. **Identifying the Enzyme**:
- The enzyme in question is succinic dehydrogenase, which is involved in the Krebs cycle and catalyzes the conversion of succinate to fumarate.

3. **Analyzing the Options**:
- The options provided are malate, malonate, malvacetate, and L-carbidolimidamide. We need to determine which of these is a known competitive inhibitor of succinic dehydrogenase.

4. **Recognizing the Competitive Inhibitor**:
- Among the options, malonate is known to be a competitive inhibitor of succinic dehydrogenase. It binds to the active site of the enzyme without undergoing a reaction, thus preventing succinate (the natural substrate) from binding.

5. **Conclusion**:
- Therefore, the correct answer to the question "A competitive inhibitor of succinic dehydrogenase is" is **malonate**.

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