Endogenous production of Niacin is from

Ans. c (Tryptophan) (Ref. Harper's Biochemistry 27th ed. 498)# Niacin is synthesized from Tryptophan.# 60 mg of Tryptophan gives 1 mg equivalent of niacin.# Active forms of Niacin, are NAD* and NADP+.Educational points:AMINO ACID DERIVATIVES# Ornithine -Putrescine - Spermidine ->>Spermine (Polyamine biosynthesis - One of the earliest signals that cells have entered their replication cycle is the appearance of elevated levels of mRNA for ornithine decarboxylase (ODC), and then increased levels of the enzyme, which is the first enzyme in the pathway to synthesis of the polyamines.)# Arginine -^Citrulline + NO