Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry & Molecular Engineering, East China University of Science & Technology, Shanghai 200237, China.
Shanghai Key Laboratory of Functional Materials Chemistry, School of Chemistry & Molecular Engineering, East China University of Science & Technology, Shanghai 200237, China.
Biosens Bioelectron. 2017 May 15;91:553-559. doi: 10.1016/j.bios.2017.01.013. Epub 2017 Jan 7.
A fluorescence "off-on" probe CMP for thiols was designed with coumarin as the fluorophore and maleimide as the receptor. The fluorescence of the coumarin was quenched through photoinduced electron transfer (PET) from the fluorophore to maleimide group. The Michael addition of the mercapto group toward maleimide formed a thioether with relatively weak fluorescence. The intramolecular nucleophilic substitution of amino group in cysteine (Cys) to alkylthio produced a much stronger fluorescent amino adduct, which was supported by UPLC-MS and NMR titration. The above sensing mechanism ensured CMP a highly sensitive probe toward Cys over GSH and Hcy. The fluorescence intensity at 495nm was linear with Cys concentration over the range of 0-10μM with a detection limit of 14nM and a rapid response time of 20min. High selectivity and good competition of the probe toward thiols over other biologically relevant species enabled us to monitor mercapto-containing proteins as well as fluorescence imaging Cys in living cells.
设计了一种以香豆素为荧光团、马来酰亚胺为受体的荧光“开-关”探针 CMP 用于检测巯基。香豆素的荧光通过荧光团到马来酰亚胺基团的光诱导电子转移（PET）猝灭。巯基与马来酰亚胺的迈克尔加成形成具有相对较弱荧光的硫醚。半胱氨酸（Cys）中的氨基基团在巯基内的分子内亲核取代生成强荧光的氨基加合物，这得到了 UPLC-MS 和 NMR 滴定的支持。上述传感机制确保 CMP 对 Cys 具有比 GSH 和 Hcy 更高的灵敏度。在 495nm 处的荧光强度与 Cys 浓度在 0-10μM 范围内呈线性关系，检测限为 14nM，响应时间快，为 20min。探针对巯基的高选择性和良好的竞争能力，使其能够监测含巯基的蛋白质以及在活细胞中进行 Cys 的荧光成像。
