The step in which `NADH + H^(+)` is not produced is : -

Options

A. Succinyl-CoA `to` Succinate
B. Pyruvate `to` Acetyl-CoA
C. `alpha` - ketoglutarate ` to` Succinyl - CoA
D. Malate `to` OAA

Answer

To solve the question regarding which step does not produce NADH + H⁺, we will analyze each option provided.

### Step-by-Step Solution:

1. **Identify the Options**: The question provides four options, and we need to evaluate each one to determine if NADH + H⁺ is produced.

2. **Evaluate Option 1: Succinyl CoA to Succinate**:
- In this step, succinyl CoA is converted to succinate.
- During this conversion, GTP (which is equivalent to ATP) is produced, but NADH + H⁺ is **not produced**.
- **Conclusion**: This option does not produce NADH + H⁺.

3. **Evaluate Option 2: Pyruvate to Acetyl CoA**:
- Here, pyruvate is converted into acetyl CoA.
- This reaction involves the decarboxylation of pyruvate and results in the production of NADH + H⁺.
- **Conclusion**: This option produces NADH + H⁺.

4. **Evaluate Option 3: Alpha-Ketoglutarate to Succinyl CoA**:
- In this step, alpha-ketoglutarate is converted to succinyl CoA.
- This reaction also produces NADH + H⁺ as a byproduct.
- **Conclusion**: This option produces NADH + H⁺.

5. **Evaluate Option 4: Malate to Oxaloacetate**:
- In this conversion, malate is oxidized to oxaloacetate.
- This reaction results in the production of NADH + H⁺.
- **Conclusion**: This option produces NADH + H⁺.

6. **Final Conclusion**:
- Based on the evaluations, the only step that does not produce NADH + H⁺ is the conversion of **succinyl CoA to succinate**.
- Therefore, the correct answer is **Option 1**.