Question
Niacin is synthesized from:
A. Phenylalanine
B. Tryptophan
C. Tyrosine
D. Methionine
Show Answer
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Correct Answer » B
Explanation
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Ans. ‘B’ Tryptophan
The liver can synthesize niacin from the essential amino acid tryptophan, but the synthesis is extremely inefficient; 60 mg of tryptophan is required to make one milligram of niacin.
Tryptophan is cleaved and rearranged with the alpha-amino group of tryptophan into the 6-membered aromatic heterocyclic compound of niacin.
