title: Enzymatic Cleavage and Subsequent Facile Intramolecular Transcyclization for in Situ Fluorescence Detection of γ-Glutamyltranspetidase Activities.
abstract: γ-Glutamyltranspetidase (GGT) is a cell-membrane-bound enzyme which selectively catalyzes cleavage of the γ-glutamyl bond of glutathione (GSH). It has been identified to be overexpressed in a number of malignant tumor cells. Therefore, fluorescent probes for fast and selective detection of GGT activities are greatly needed. However, the majority of currently available GGT fluorescent probes based on direct conjugation of a γ-glutamyl group to a specific fluorophore generally has slow enzymatic kinetics due to bulky fluorophore too close to the enzyme's active site. Moreover, the uncaged fluorophore with a free amine group might undergo oxidation or other enzymatic transformation and resulted in a complicated time-dependent fluorescence response. Herein, we reported design of a novel fluorescent GGT probe NM-GSH (2), which incorporated a fast intramolecular transcyclization cascade for rapid detection of GGT activities after enzymatic cleavage of the γ-glutamyl group. This design strategy allows introduction of bulky 1,8-naphthalimide fluorophore with improved enzymatic kinetics and lowered detection limit. The transcyclized product 4 gives more than 200-fold fluorescence increment. The probe NM-GSH showed both good selectivity and fast detection of GGT activities with the detection limit as low as 0.21 mU/mL. In addition, the fluorescent product 4 contains no free amine group and is more stable for detection. Most importantly, cell imaging studies showed that the transcyclized product 4 was enriched in lysosomes for selectively lighting up GGT-overexpressed ovarian cancer cells (OVCAR5) but not normal cells (HUVEC), indicating NM-GSH's potentials as an imaging agent in cancer diagnosis and treatment.
authors: Shanghai Key Laboratory of New Drug Design, Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, and State Key Laboratory of Bioengineering Reactor, East China University of Science & Technology , 130 Meilong Road, Shanghai 200237, China.
authors: Hongjuan
authors: H
authors: Tong
authors: Shanghai Key Laboratory of New Drug Design, Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, and State Key Laboratory of Bioengineering Reactor, East China University of Science & Technology , 130 Meilong Road, Shanghai 200237, China.
authors: Yongjun
authors: Y
authors: Zheng
authors: Shanghai Key Laboratory of New Drug Design, Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, and State Key Laboratory of Bioengineering Reactor, East China University of Science & Technology , 130 Meilong Road, Shanghai 200237, China.
authors: Li
authors: L
authors: Zhou
authors: Shanghai Key Laboratory of New Drug Design, Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, and State Key Laboratory of Bioengineering Reactor, East China University of Science & Technology , 130 Meilong Road, Shanghai 200237, China.
authors: Xiangmin
authors: X
authors: Li
authors: Shanghai Key Laboratory of New Drug Design, Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, and State Key Laboratory of Bioengineering Reactor, East China University of Science & Technology , 130 Meilong Road, Shanghai 200237, China.
authors: Rui
authors: R
authors: Qian
authors: Shanghai Key Laboratory of New Drug Design, Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, and State Key Laboratory of Bioengineering Reactor, East China University of Science & Technology , 130 Meilong Road, Shanghai 200237, China.
authors: Rui
authors: R
authors: Wang
authors: Shanghai Key Laboratory of New Drug Design, Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, and State Key Laboratory of Bioengineering Reactor, East China University of Science & Technology , 130 Meilong Road, Shanghai 200237, China.
authors: Jianhong
authors: J
authors: Zhao
authors: Shanghai Key Laboratory of New Drug Design, Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, and State Key Laboratory of Bioengineering Reactor, East China University of Science & Technology , 130 Meilong Road, Shanghai 200237, China.
authors: Kaiyan
authors: K
authors: Lou
authors: Shanghai Key Laboratory of New Drug Design, Shanghai Key Laboratory of Chemical Biology, School of Pharmacy, and State Key Laboratory of Bioengineering Reactor, East China University of Science & Technology , 130 Meilong Road, Shanghai 200237, China.|Department of Chemistry and Chemical Biology, University of New Mexico , Albuquerque, New Mexico 87131-0001, United States.
authors: Wei
authors: W
authors: Wang
mesh_terms: D045744:Cell Line, Tumor; D003500:Cyclization; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000138:chemical synthesis / Q000737:chemistry*; D061307:Human Umbilical Vein Endothelial Cells / Q000201:enzymology; D006801:Humans; D018613:Microscopy, Confocal; D015394:Molecular Structure; D005723:gamma-Glutamyltransferase / Q000032:analysis* / Q000378:metabolism*
chemical_list: D005456:Fluorescent Dyes; D005723:gamma-Glutamyltransferase