Identify A and B in the given reaction.
Pyruvic acid `+CoA + NAD^(+) overset(Mg^(2+))underset("Pyruvate dehydrogenase")rarr A+B +NADH +H^(+)`

Options

A. `{:(A,B),(PEP,CO_(2)):}`
B. `{:(A,B),("Acetyl" CoA,CO_(2)):}`
C. `{:(A,B),(CO_(2),H_(2)O):}`
D. `{:(A,B),("Acetyl" CoA,H_(2)O):}`

Answer

To identify A and B in the given reaction, we need to analyze the components and the process involved in the conversion of pyruvic acid.

### Step-by-step Solution:

1. **Understanding the Reaction**: The reaction given is:
\[ \text{Pyruvic acid} + \text{CoA} + \text{NAD}^+ \overset{\text{Mg}^{2+}}{\underset{\text{Pyruvate dehydrogenase}}{\rightarrow}} A + B + \text{NADH} + \text{H}^+ \]
This reaction involves pyruvic acid, coenzyme A (CoA), and NAD^+ as reactants.

2. **Role of Enzymes and Cofactors**: The reaction is facilitated by the enzyme pyruvate dehydrogenase in the presence of magnesium ions (Mg^2+). The pyruvate dehydrogenase complex is crucial for this conversion.

3. **Decarboxylation and Oxidation**: Pyruvic acid undergoes decarboxylation (removal of a carbon atom in the form of carbon dioxide) and oxidation. This is a key step that transforms pyruvic acid into other products.

4. **Identifying Products**: The products of this reaction include:
- Acetyl CoA (A)
- Carbon dioxide (B)
- NADH
- Hydrogen ion (H^+)

5. **Final Identification**: Based on the above steps, we can conclude that:
- A = Acetyl CoA
- B = Carbon dioxide

### Final Answer:
- A = Acetyl CoA
- B = Carbon dioxide

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