<prompt> Which of the soluble vitamin is synthesized in the body?ThiamineVitamin CNiacinPyridoxine  <response>: Not strictly a Vitamin Can be synthesized from Tryptophan Dietary nicotinamide, niacin and tryptophan an essential amino acid contribute to the synthesis of the coenzymes- nicotinamide adenine dinucleotide NAD and nicotinamide adenine dinucleotide phosphate NADP Nicotinamide is deaminated in the body to niacin Tryptophan produces quinolinate which then forms nicotinate mononucleotide and, ultimately, NAD and NADP Sixty milligrams of tryptophan is equivalent to 1 mg of niacin for the synthesis of niacin coenzymes ref Satyanarayana biochemistry 4th ed page 140 