A real‐time fluorescence assay for protease activity and inhibitor screening based on the aggregation‐caused quenching of a perylene probe

Abstract

We have established a real-time and label-free fluorescence turn-on strategy for protease activity detection and inhibitor screening via peptide-induced aggregation-caused quenching of a perylene probe. Because of electrostatic interactions and high hydrophilicity, poly-l-glutamic acid sodium salt (PGA; a negatively charged peptide) could induce aggregation of a positively charged perylene probe (probe 1) and the monomer fluorescence of probe 1 was effectively quenched. After a protease was added, PGA was enzymatically hydrolyzed into small fragments and probe 1 disaggregated. The fluorescence recovery of probe 1 was found to be proportional to the concentration of protease in the range from 0 to 1 mU/ml. The detection limit was down to 0.1 mU/ml. In the presence of a protease inhibitor, protease activity was inhibited and fluorescence recovery reduced. Moreover, we demonstrated the potential application of our method in a complex mixture sample including 1% human serum. Our method is simple, fast and cost effective.

Progress in organic fluorescent probes for detecting metal ions in environment

“…食用过量的铝离子极易导致阿 尔茨海默病、帕金森综合征等重大疾病 [5] [17,18] 、分子内电荷转 移(intramolecular charge transfer, ICT)机理 [19] 、荧光共 振能量转移(fluorescence resonance energy transfer, FRET)机理 [20,21] 和跨键能量转移(through-bond energy transfer, TBET)机理 [22] . 在分子的聚集-解聚中 [23,24] , 根 据聚集状态下荧光核发光性质的不同, 又可分为聚集 诱导荧光猝灭效应(aggregation-caused quenching, ACQ) [25,26] 和聚集诱导发光(aggregation-induced emission, AIE) [27~29] . 这些有机分子的独特机理, 为设计有 机荧光金属探针提供了前提条件.…”