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 in which reaction oxidative decarboxylation does not occur, we will analyze each option provided in the question.

### Step-by-Step Solution:

1. **Understanding Decarboxylation**:
- Decarboxylation is the process of removing a carboxyl group (-COOH) from a molecule, which results in the release of carbon dioxide (CO2). Oxidative decarboxylation specifically involves the oxidation of the substrate along with the decarboxylation.

2. **Analyzing Each Reaction**:
- **Option 1: Malic acid to Pyruvic acid**:
- Malic acid (C4) converts to pyruvic acid (C3). Here, one carbon is lost as CO2, indicating decarboxylation occurs.

- **Option 2: Pyruvic acid to Acetyl Coenzyme A**:
- Pyruvic acid (C3) converts to acetyl CoA (C2). Again, one carbon is lost as CO2, indicating decarboxylation occurs.

- **Option 3: Glyceraldehyde 3-phosphate (G3P) to 1,3-bisphosphoglycerate (1,3-BPGA)**:
- G3P (C3) converts to 1,3-BPGA (C3). There is no loss of carbon; hence, no decarboxylation occurs in this reaction.

- **Option 4: Alpha-ketoglutaric acid to Succinyl Coenzyme A**:
- Alpha-ketoglutaric acid (C5) converts to succinyl CoA (C4). One carbon is lost as CO2, indicating decarboxylation occurs.

3. **Conclusion**:
- The only reaction where oxidative decarboxylation does not occur is the conversion of Glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate (Option 3).

### Final Answer:
**Glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate** does not involve oxidative decarboxylation.

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