化学
谷胱甘肽
苯并噻唑
半胱氨酸
分子内力
荧光
光化学
硫酯
部分
立体化学
生物化学
酶
量子力学
物理
作者
Xiaofeng Yang,Qian Huang,Yaogang Zhong,Zheng Li,Hua Li,Mark Lowry,Jorge O. Escobedo,Robert M. Strongin
出处
期刊:Chemical Science
[The Royal Society of Chemistry]
日期:2014-01-01
卷期号:5 (6): 2177-2177
被引量:322
摘要
Many studies have shown that glutathione (GSH) and cysteine (Cys)/homocysteine (Hcy) levels are interrelated in biological systems. To unravel the complicated biomedical mechanisms by which GSH and Cys/Hcy are involved in various disease states, probes that display distinct signals in response to GSH and Cys/Hcy are highly desirable. In this work, we report a rhodol thioester (1) that responds to GSH and Cys/Hcy with distinct fluorescence emissions in neutral media. Probe 1 reacts with Cys/Hcy to form the corresponding deconjugated spirolactam via a tandem native chemical ligation (NCL) reaction. This intramolecular spirocyclization leads to the “quinone–phenol” transduction of rhodol dyes, and an excited-state intramolecular proton transfer (ESIPT) process between the phenolic hydroxyl proton and the aromatic nitrogen in the benzothiazole unit occurs upon photoexcitation, thus affording 2-(2′-hydroxyphenyl) benzothiazole (HBT) emission (454 nm). In the case of the tripeptide GSH, only transthioesterification takes place removing the intramolecular photo-induced electron transfer (PET) process caused by the electron deficient 4-nitrobenzene moiety giving rise to a large fluorescence enhancement at the rhodol emission band (587 nm). The simultaneous detection of GSH and Cys/Hcy is attributed to the significantly different rates of intramolecular S,N-acyl shift of their corresponding thioester adducts derived from 1. The utility of probe 1 has been demonstrated in various biological systems including serum and cells.
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