Question:
The activity of enzyme Pyruvate Dehydrogenase is regulated by which one of the following modifications?
The activity of enzyme Pyruvate Dehydrogenase is regulated by which one of the following modifications?
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PDH regulation:
- Phosphorylation: Inactivates PDH.
- Dephosphorylation: Activates PDH.
- PDH kinase and PDH phosphatase are the regulatory enzymes.
- Phosphorylation: Inactivates PDH.
- Dephosphorylation: Activates PDH.
- PDH kinase and PDH phosphatase are the regulatory enzymes.
Updated On: Sep 1, 2026
- Phosphorylation/Dephosphorylation
- Carboxylation/Decarboxylation
- Methylation/Demethylation
- Glucosylation/Deglucosylation
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The Correct Option is A
Solution and Explanation
Step 1: Understanding the Question:
This question tests knowledge of enzyme regulation mechanisms.
Step 2: Detailed Explanation:
Pyruvate dehydrogenase (PDH) is regulated by reversible phosphorylation.
- Phosphorylation: Inactivates PDH (by PDH kinase).
- Dephosphorylation: Activates PDH (by PDH phosphatase).
This is a classical example of covalent modification regulation.
Carboxylation/Decarboxylation (B): Not used for PDH.
Methylation/Demethylation (C): Not used for PDH.
Glucosylation/Deglucosylation (D): Not used for PDH.
Thus, PDH activity is regulated by phosphorylation/dephosphorylation.
Step 3: Final Answer:
Thus, PDH is regulated by phosphorylation/dephosphorylation, which corresponds to option (A).
[0.5cm]
This question tests knowledge of enzyme regulation mechanisms.
Step 2: Detailed Explanation:
Pyruvate dehydrogenase (PDH) is regulated by reversible phosphorylation.
- Phosphorylation: Inactivates PDH (by PDH kinase).
- Dephosphorylation: Activates PDH (by PDH phosphatase).
This is a classical example of covalent modification regulation.
Carboxylation/Decarboxylation (B): Not used for PDH.
Methylation/Demethylation (C): Not used for PDH.
Glucosylation/Deglucosylation (D): Not used for PDH.
Thus, PDH activity is regulated by phosphorylation/dephosphorylation.
Step 3: Final Answer:
Thus, PDH is regulated by phosphorylation/dephosphorylation, which corresponds to option (A).
[0.5cm]
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