Malonic acid decreases the catalytic efficiency of

Options

A. Malate dehydrogenase
B. A keto glutaric dehydrogenase
C. Succinic dehydrogenase
D. Citric synthetase

Answer

To solve the question "Malonic acid decreases the catalytic efficiency of," we will follow these steps:

### Step-by-Step Solution:

1. **Understanding the Role of Malonic Acid**:
- Malonic acid is known to act as a competitive inhibitor in biochemical reactions. This means it competes with the substrate for the active site of an enzyme.

2. **Identifying the Enzyme**:
- The question provides four options: malate dehydrogenase, ketoglutaric dehydrogenase, succinic dehydrogenase, and citric synthetase. We need to determine which enzyme is affected by malonic acid.

3. **Mechanism of Competitive Inhibition**:
- In competitive inhibition, the inhibitor (in this case, malonic acid) binds to the active site of the enzyme, preventing the substrate from binding. This reduces the rate of reaction and thus decreases the catalytic efficiency of the enzyme.

4. **Specificity of Malonic Acid**:
- Malonic acid specifically inhibits succinic dehydrogenase by occupying its active site. This means that when malonic acid is present, succinic dehydrogenase cannot effectively catalyze its reaction because the substrate cannot bind.

5. **Conclusion**:
- Based on the above understanding, we conclude that malonic acid decreases the catalytic efficiency of succinic dehydrogenase.

### Final Answer:
Malonic acid decreases the catalytic efficiency of **succinic dehydrogenase**.

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