College of Chemistry & Chemical Engineering, Central South University, Changsha, Hunan 410083, China.
Department of Chemistry and COSDAF (Centre of Super-Diamond and Advanced Films), City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong 999077, China.
ACS Appl Bio Mater. 2021 Aug 16;4(8):6558-6564. doi: 10.1021/acsabm.1c00715. Epub 2021 Aug 3.
Lysine (Lys) and arginine (Arg), as two of the most alkaline amino acids among 20 common amino acids, are closely involved in many vital biological processes and biomaterial synthesis. Abnormal levels of Lys and Arg can lead to various diseases. Although a limited number of fluorescent probes for Lys and Arg have been reported, many of them are not sensitive enough due to the moderate fluorescence signal and on-off mode. In addition, none of them were applied for detecting amine groups in solid-phase peptide synthesis. In this study, we designed and synthesized optical fluorescent probe based on the benzoxadiazole fluorophore, which could undergo an accelerated hydrolysis reaction under basic conditions. Probe revealed excellent selectivity toward alkaline Lys and Arg over other common amino acids with both fluorometric and colorimetric readouts. After treatment with Lys and Arg, probe could emit a turn-on fluorescent response at 580 nm with a distinct color change from pink to yellow. The limit of detection for Lys and Arg was calculated to be 1.1 and 1.39 μM, respectively. We also successfully applied probe for the visualization of Arg in living cells. Moreover, to the best of our knowledge, probe provided the first fluorescent platform to detect -NH groups in solid-phase synthesis of peptides with distinct fluorescent and colorimetric changes. We envision that the probe can provide an alternative method for the traditional Kaiser test.
赖氨酸（Lys）和精氨酸（Arg）作为 20 种常见氨基酸中最碱性的两种氨基酸，它们密切参与许多重要的生物过程和生物材料的合成。Lys 和 Arg 水平异常可导致各种疾病。尽管已经报道了一些用于 Lys 和 Arg 的荧光探针，但由于荧光信号适中且开-关模式，许多探针不够灵敏。此外，它们都没有用于固相肽合成中胺基的检测。在本研究中，我们设计并合成了基于苯并恶二唑荧光团的光学荧光探针，该探针在碱性条件下可发生加速水解反应。探针在荧光和比色读数方面均对碱性 Lys 和 Arg 具有出色的选择性，优于其他常见氨基酸。用 Lys 和 Arg 处理后，探针在 580nm 处发出开启式荧光响应，颜色从粉红色变为黄色。Lys 和 Arg 的检测限分别计算为 1.1 和 1.39μM。我们还成功地将探针应用于活细胞中 Arg 的可视化。此外，据我们所知，探针为检测固相肽合成中-NH 基团提供了第一个具有明显荧光和比色变化的荧光平台。我们设想该探针可以为传统的凯泽测试提供替代方法。
