posted on 2023-10-19, 22:35authored byHongyu Wen, Minhui Shen, Zhisheng Lai, Xiaoru Peng, Yu-Xin Ye, Jianqiao Xu, Gangfeng Ouyang
Identifying
contaminants of specific bioactivities from
complicated
environmental matrices remains costly and time-consuming, as it requires
us to not only resolve their structures but also determine their bioactivities.
Herein, a novel noncovalent tagging method is integrated in mass spectrometry
for identifying unknown contaminants that target dopamine (DA) receptors.
Via proteolysis of bovine serum albumin, a stereoselective hexapeptide
(ACFAVE) is selected for noncovalently tagging the contaminants that
possess the stereostructural characteristics of binding to DA receptors.
The tagged contaminants can be readily distinguished from the coexisting
species for subsequent structural analysis based on the tagging-induced
shifts of the mass-to-charge ratios. Thus, both bioactivity evaluation
and structure analysis are accomplished via mass spectrometry. By
using this method, 1,3-diphenylguanidine (DPG), a widely used additive
in rubber and plastics, is successfully identified out of 2495 features
detected in the Pearl River water, with its concentration determined
as only 9.8 μg L–1. Furthermore, DPG is confirmed
as a potential disrupter to the DA receptors via a simulated docking
experiment, which has not been reported before. The present noncovalent
tagging method provides a cost-effective and time-efficient way of
identifying bioactive molecules in complicated matrices. And proteolysis
of proteins is promising for developing more taggants with other desired
stereoselectivities in the future.