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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.
user
Serotonin can be synthesized from
assistant
The correct answer is  In bacteria that synthesize tryptophan, high cellular levels of this amino acid activate a repressor protein, which binds to the trpoperon. Binding of this repressor to the tryptophan operon prevents transcription of downstream DNA that codes for the enzymes involved in the biosynthesis of tryptophan Refer kDT 7/e p170