0 votes 0 votes Which of the following chemical messenger(s) is/are derivative(s) of tryptophan? $\gamma$-amino butyric acid Indole acetic acid Melatonin Serotonin Others gatebt-2021 multiple-selects + – go_editor asked Mar 1, 2021 retagged Mar 7, 2021 by Lakshman Bhaiya go_editor 1.4k points answer comment Share Follow See all 0 reply Please log in or register to add a comment.