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Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
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The rate limiting step for norepinephrine synthesis is:
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The correct answer is  Ans. (B) Conversion of tyrosine to DOPA(Ref: Katzung 10/e p78; KDT 8th/e p136)Rate limiting enzyme in norepinephrine synthesis is tyrosine hydroxylase that catalyses the conversion of tyrosine to dopa. In ACh synthesis, rate limiting step is uptake of choline by the neurons.