<prompt> Which vitamin can be synthesized from tryptophan:NiacinRiboflavinCobalaminFolic acid  <response>: Ans. a NiacinRef: Harpers Biochemistry, 30th ed. pg. 557 Niacin is synthesized from tryptophan via kynurenine and quinolinic acids as key biosynthetic intermediates. Refer to above explanation for more details. 