Which of the following is not a derivative of the amino acid (Tryptophan)?

Posted by: Pdfprep Category: USMLE Tags: USMLE exam questions, USMLE practice exam, USMLE certification Post Date: November 2, 2020

Which of the following is not a derivative of the amino acid (Tryptophan)?
A . Melatonin
B . Serotonin
C . Creatine
D . Niacin

Answer: C