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Which enzyme is responsible for conversi...

Which enzyme is responsible for conversion of norepinephrine to epinephrine?
(a) Catecholamine-O-methyl transferase
(b) Phenylalanine-N-methyl transferase
(c) DOPA carboxylase
(d) Monoamine oxidase

A

Catecholamine-O-methyl transferase

B

Phenylalanine-N-methyl transferase

C

DOPA carboxylase

D

Monoamine oxidase.

Text Solution

AI Generated Solution

The correct Answer is:
To determine which enzyme is responsible for the conversion of norepinephrine to epinephrine, we can analyze each option provided in the question step by step. ### Step-by-Step Solution: 1. **Understanding the Question**: The question asks for the enzyme that converts norepinephrine (noradrenaline) to epinephrine (adrenaline). 2. **Analyzing Option (a): Catecholamine-O-methyl transferase**: - This enzyme is primarily involved in the degradation of catecholamines rather than their synthesis. Therefore, it does not facilitate the conversion of norepinephrine to epinephrine. - **Conclusion**: This option is incorrect. 3. **Analyzing Option (b): Phenylalanine-N-methyl transferase (PNMT)**: - PNMT is known to be found in the adrenal medulla and is specifically responsible for converting norepinephrine into epinephrine. This makes it a strong candidate for the correct answer. - **Conclusion**: This option is correct. 4. **Analyzing Option (c): DOPA carboxylase**: - DOPA carboxylase is involved in the conversion of aromatic amino acids, particularly in the synthesis of dopamine from L-DOPA. It does not play a role in the conversion of norepinephrine to epinephrine. - **Conclusion**: This option is incorrect. 5. **Analyzing Option (d): Monoamine oxidase**: - Monoamine oxidase is an enzyme that degrades monoamines, including norepinephrine and epinephrine. It does not facilitate their conversion. - **Conclusion**: This option is incorrect. ### Final Answer: The enzyme responsible for the conversion of norepinephrine to epinephrine is **(b) Phenylalanine-N-methyl transferase (PNMT)**. ---
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