Thiols are critical to cellular structures and functions. Disturbance of cellular thiols has been found to affect cell functions and cause various diseases. Intracellularly, thiols were found unevenly distributed in subcellular organelles. Probes capable of detecting subcellular thiol density in live cells are valuable tools in determining thiols’ roles at the subcellular level. The subcellular organelle lysosome is the place where unwanted macromolecules are removed through degradation by hydrolytic enzymes. The degradation also serves as a regulation of a variety of cellular functions such as autophagy, endocytosis, and phagocytosis to maintain cellular homeostasis. Thiols are found to be involved in the lysosomal degradation process. A probe that can detect lysosomal thiols in live cells will be a valuable tool in unveiling the roles of thiols in lysosomes. We would like to report bis(7-(N-(2-morpholinoethyl)sulfamoyl)benzo[c][1,2,5]-oxadiazol-5-yl)sulfane (BISMORX) as a thiol specific fluorogenic agent for live cell nonprotein thiol (NPSH) imaging in lysosomes through fluorescence microscopy. BISMORX itself shows no fluorescence and reacts readily with a NPSH to form a fluorescent thiol adduct with excitation and emission wavelengths of 380 and 540 nm, respectively. BISMORX does not react with compounds containing nucleophilic functional groups other than thiols such as −OH, −NH₂, and −COOH. No reaction was observed either when BISMORX was mixed with protein thiols. BISMORX was able to image, quantify, and detect the change of NPSH in lysosomes in live cells. A colocalization experiment with LysoTracker Red DND-99 confirmed that the thiols imaged by BISMORX were indeed lysosomal thiols.

中文翻译：

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双（7-（N-（2-吗啉代乙基）氨磺酰基）苯并[ c ] [1,2,5]恶二唑-5-基）硫烷的设计，合成及表征，用于活细胞溶酶体中的非蛋白质巯基成像。

硫醇对细胞结构和功能至关重要。已经发现细胞硫醇的紊乱会影响细胞功能并引起多种疾病。在细胞内，发现硫醇在亚细胞细胞器中分布不均。能够检测活细胞中亚细胞巯基密度的探针是确定亚细胞水平上硫醇作用的有价值的工具。亚细胞器溶酶体是通过水解酶降解除去不需要的大分子的地方。降解还用作调节多种细胞功能，例如自噬，内吞作用和吞噬作用以维持细胞稳态。发现硫醇参与了溶酶体降解过程。可以检测活细胞中溶酶体硫醇的探针将是揭示硫醇在溶酶体中作用的有价值的工具。我们想报告bis（7-（N-（2-吗啉代乙基）氨磺酰基）苯并[ c ] [1,2,5]-恶二唑-5-基）亚砜（BISMORX）作为硫醇特异性荧光剂，用于溶酶体中活细胞非蛋白硫醇（NPSH）的荧光成像显微镜检查。BISMORX本身不显示荧光，并且容易与NPSH反应形成激发和发射波长分别为380和540 nm的荧光硫醇加合物。BISMORX不与包含除硫醇以外的亲核官能团的化合物反应，例如-OH，-NH ₂和-COOH。当BISMORX与蛋白质硫醇混合时，也未观察到反应。BISMORX能够成像，定量和检测活细胞中溶酶体中NPSH的变化。与LysoTracker Red DND-99的共定位实验证实，BISMORX成像的硫醇确实是溶酶体硫醇。