An enzyme-activated NIR fluorescent probe for detecting bacterial glutamyltranspeptidase (γ-GT) and high-throughput screening of its inhibitors

γ-Glutamyltransferase (γ-GT) is an essential biological enzyme for bacteria proliferation and infection, which is regarded as a virulence factor of pathogenic bacteria. On the basis of hydrolysis function of γ-GT, an enzyme-activated NIR fluorescent probe (DDAG) was designed and developed for sensing γ-GT activity. Herein, the endogenous bacterial γ-GT was detected in real time, and further various bacteria were imaged in vitro. Furthermore, a high-throughput screening system based on DDAG was established for effectively screening γ-GT potent inhibitors from natural compounds and herbal medicines library. Finally, baicalein, myricetin and amaronol A from herbal medicines were solidly confirmed as the novel inhibitors of bacterial γ-GT for the first time.