Biotin-Labeled Serotonin

Other studies used biotinylated serotonin for transglutaminase reactions (Watts et al., 2009). However, when biotin is linked to the amino group of serotonin, TG can not anymore use the adduct as substrate. Moreover the molecule gets very large and can not enter cells anymore. Therefore biorthogonal labeling was developed which used a small alkyne-functionalized serotonin, which can be taken up in cells for the transglutaminase reaction (Lin et al., 2013, 2014). Afterwards a biotin-residue is specifically linked by click-chemistry to this incorporated propargylated serotonin. The biotin-label then allows purification and detection of the serotonylated protein on Western blots and by mass spectrometry (Lin et al., 2013, 2014; Farrelly et al., 2019).