Question
Niacin is synthesized from:
A. Phenylalanine
B. Tryptophan
C. Tyrosine
D. Methionine
Show Answer
|
Correct Answer » B Explanation |
 |
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.