In which one of the following reactions, oxidative decarboxylation does not occur ?

Options

A. Malic acid `rarr` Pyruvic acid
B. Pyruvic acid `rarr` Acetyl Co - A
C. Glyceraldehyde 3- phosphate `rarr` 1,3 bisphosphoglyceric acid
D. `alpha` ketoglutaric acid `rarr` Succinyl Co - A

Answer

To determine which reaction does not involve oxidative decarboxylation, we need to analyze each option provided in the question.

### Step-by-step Solution:

1. **Understanding Oxidative Decarboxylation**:
- Oxidative decarboxylation is a biochemical process where a carboxyl group is removed from a substrate as carbon dioxide (CO2), and the substrate is oxidized in the process.

2. **Analyzing Each Option**:
- **Option A: Malic acid to pyruvic acid**:
- In this reaction, malic acid loses a CO2 molecule and is converted to pyruvic acid. This is an example of oxidative decarboxylation.

- **Option B: Pyruvic acid to acetyl coenzyme A**:
- Here, pyruvic acid also loses a CO2 molecule during its conversion to acetyl coenzyme A. This is another example of oxidative decarboxylation.

- **Option C: Glyceraldehyde-3-phosphate to 1,3-bisphosphoglyceric acid**:
- In this reaction, there is no loss of CO2. Glyceraldehyde-3-phosphate is converted to 1,3-bisphosphoglyceric acid without any decarboxylation occurring. Therefore, this is not an example of oxidative decarboxylation.

- **Option D: Alpha-ketoglutaric acid to succinyl coenzyme A**:
- In this reaction, alpha-ketoglutaric acid loses a CO2 molecule and is converted to succinyl coenzyme A. This is also an example of oxidative decarboxylation.

3. **Conclusion**:
- The only reaction that does not involve oxidative decarboxylation is **Option C: Glyceraldehyde-3-phosphate to 1,3-bisphosphoglyceric acid**.

### Final Answer:
**C. Glyceraldehyde-3-phosphate to 1,3-bisphosphoglyceric acid**