Three fluorescent probes TP1–3 for thiols were rationally designed and synthesized to distinguish cysteine (Cys) from glutathione (GSH)/homocysteine (Hcy). TP1–3 are almost non-fluorescent and colorless 4-nitro-1,8-naphthalimide derivatives. Upon the substitution of nitro by Cys, TP1–3 were transformed into weakly fluorescent green-emitting 4-amino analogs via highly fluorescent blue-emitting thioether intermediates. The three-channel signaling capability allows discrimination between Cys and GSH/Hcy. The fluorescence intensity at 498 nm was linearly proportional to GSH concentration in the range of 0–20 μM, and the detection limit was 5 × 10−8 mol L−1. A good linear relationship between A446/A350 and Cys concentration was found in the range of 0–70 μM, and the detection limit was 2 × 10−7 mol L−1. Moreover, TP3 was used for living cell imaging as well as for detecting mercapto-containing proteins.
为了区分半胱
氨酸(Cys)和
谷胱甘肽(GSH)/高半胱
氨酸(Hcy),我们合理设计并合成了三种
硫醇荧光探针 TP1-3。TP1-3 几乎是无色无荧光的 4-硝基-1,8-
萘二甲
酰亚胺衍
生物。用 Cys 取代硝基后,TP1-3 通过高荧光蓝色
硫醚中间体转变为弱荧光绿色发光的 4-
氨基类似物。三通道信号传导能力可以区分 Cys 和 GSH/Hcy。在 0-20 μM 范围内,498 nm 处的荧光强度与 GSH 浓度成线性比例,检测限为 5 × 10-8 mol L-1。在 0-70 μM 范围内,A446/A350 与 Cys 浓度呈良好的线性关系,检测限为 2 × 10-7 mol L-1。此外,TP3 还可用于活细胞成像以及检测含巯基的蛋白质。