What amount of tryptophan produces 1 gm of niacin?
Ans. c (60mg). (Ref. Harper, Biochemistry, 26th ed., 258)NIACIN (Vitamin B3)# Niacin is derived from tryptophan using vitamin B6; 1 mg of niacin is formed from 60 mg of tryptophan.# Niacin is constituent of NAD+, NADP+ (used in redox reactions).# Niacin deficiency results in Pellagra; The symptoms of Pellagra are the 4 D's:- Diarrhea,- Dermatitis (Necklace sign),- Dementia and- Death# Pellagra can be caused by:- Hartnup disease (| tryptophan absorption),- Malignant carcinoid syndrome (| tryptophan metabolism), and- INH (| vitamin B6).AMINO ACID DERIVATIVES1TryptophanNiacin =>>NAD+/NADP+(1 mg of niacin is formed from 60 mg of tryptophan; Synthesis requires B6).Serotonin =Melatonin2PhenylalaninePhenylalanine => tyrosine =>dopa =>dopamine => Norepinephrine => epinephrinePhenylalanine =>tyrosine =>dopa =>melanin.Phenylalanine =>tyrosine =>thyroxine3Histidine# Histamine (By decarboxylation).4Glycine# Porphyrin and haem# Purines# Creatine (totally made-up of glycine + arginine + methionine; mnemonic--GAM)# Glutathione (totally made up of glycine + cystine+ glutamate; mnemonic--GCG)5ArginineCreatinine, Urea, Nitric oxide6MethionineCholine7GlutamateGABA (glutamate decarboxylase--requires B6).Glutathione
40 mg
50 mg
60 mg
70 mg
Proteins and Amino Acids