Fig. 2
From: Biosynthesis of melatonin from l-tryptophan by an engineered microbial cell factory
UPLC–MS/MS analysis of melatonin from BL7992. A Extracted ion chromatogram (XIC) of melatonin. B Primary mass spectrum of melatonin product (m/z (ES +): 232.1 [M + H]+). C Secondary mass spectrum of melatonin product (m/z (ES +): 174.0 [M + H].+)