Which of the following enzyme of Krebs cycle is found attached to inner mitochondrial membrane ?

Options

A. Succinate dehydrogenase
B. Malic dehydrogenase
C. Isocitrate dehydrogenase
D. Citrate synthetase

Answer

To solve the question about which enzyme of the Krebs cycle is found attached to the inner mitochondrial membrane, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Krebs Cycle**: The Krebs cycle, also known as the citric acid cycle or tricarboxylic acid (TCA) cycle, is a series of chemical reactions used by all aerobic organisms to generate energy.

2. **Identify the Enzymes in the Krebs Cycle**: The enzymes involved in the Krebs cycle include:
- Citrate synthase
- Isocitrate dehydrogenase
- Alpha-ketoglutarate dehydrogenase
- Succinyl-CoA synthetase
- Succinate dehydrogenase
- Fumarase
- Malate dehydrogenase

3. **Locate the Enzymes**: Most of these enzymes are found in the mitochondrial matrix, which is the fluid-filled space inside the mitochondria. However, we need to identify which enzyme is attached to the inner mitochondrial membrane.

4. **Analyze the Options**:
- **Succinate dehydrogenase**: This enzyme is unique as it is the only enzyme of the Krebs cycle that is embedded in the inner mitochondrial membrane. It catalyzes the conversion of succinate to fumarate.
- **Malic dehydrogenase**: This enzyme is located in the mitochondrial matrix.
- **Isocitrate dehydrogenase**: This enzyme is also found in the mitochondrial matrix.
- **Citrate synthase**: This enzyme is located in the mitochondrial matrix as well.

5. **Conclude the Answer**: Based on the analysis, the only enzyme of the Krebs cycle that is attached to the inner mitochondrial membrane is **succinate dehydrogenase**.

### Final Answer:
The enzyme of the Krebs cycle that is found attached to the inner mitochondrial membrane is **succinate dehydrogenase**.

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