Malic dehydrogenase enzyme is present in

Options

A. Mitochondria
B. Chloroplast
C. Cytosol
D. 1 & 2

Answer

**Step-by-Step Solution:**

1. **Understanding Malic Dehydrogenase**: Malic dehydrogenase is an enzyme that plays a crucial role in the oxidative pathway. It is involved in the conversion of malic acid to oxaloacetate.

2. **Function of Malic Dehydrogenase**: This enzyme catalyzes the interconversion of malate (malic acid) to oxaloacetate, a key step in the citric acid cycle and other metabolic pathways.

3. **Co-factors Involved**: The reaction catalyzed by malic dehydrogenase involves the co-factor NAD+ (Nicotinamide adenine dinucleotide), which is reduced to NADH in the process.

4. **Location of Malic Dehydrogenase**: Malic dehydrogenase is found in two main cellular organelles:
- **Mitochondria**: This is where it participates in the citric acid cycle (Krebs cycle).
- **Chloroplasts**: In plants, it is also present in chloroplasts, where it plays a role in photosynthesis.

5. **Conclusion**: Therefore, malic dehydrogenase is present in both mitochondria and chloroplasts.

**Final Answer**: Malic dehydrogenase enzyme is present in mitochondria and chloroplasts.

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