脂质体荧光探针检测磷脂酶C的活性

建立了一种以荧光标记脂质体为探针检测磷脂酶 C (PLC) 活性的新方法.此荧光探针是由二棕榈酰磷脂酰胆碱(DPPC)和丽丝胺罗丹明B标记的荧光磷脂(Liss Rhod PE)通过自组装形成有序的荧光标记脂质体,探针脂质体中Liss Rhod PE由于相互之间距离靠近产生自猝灭效应,因而作为探针的脂质体并不表现出荧光性质.当在此探针溶液中加入目标物PLC,PLC可以水解切割标记在磷脂酰基二位上的荧光团罗丹明,使其从脂质体释放到溶液中,导致自猝灭效应的减弱,溶液荧光信号增强,以此实现对PLC活性的检测.使用此探针检测PLC活性,荧光强度的增加值与PLC浓度在5~300 U/L范围内呈良好的线性关系,检出限为2 U/L(S/N=3).此外,此探针还可用于PLC抑制剂的筛选.

Fluorescence Assay for Phospholipase C Activity Using Liposome Probes

A simple assay for detection of phospholipase C (PLC) activity was developed based on a fluorescence liposome probe using the Liss Rhod PE-loaded phospholipid liposomes.The liposome probe was prepared by the coassembly of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC) and fluorescent lipid (Liss Rhod PE).The probe showed very low background fluorescence due to fluorescence self-quenching effect of Liss Rhod PE.As the PLC enzyme selectively digested lipid, the Rhod fluorescence was recovered from its quenched state, leading to the sensitive detection of PLC.This assay provided a limit of detection (at a signal-to-noise ratio of 3) of 2 U/L for PLC.In the presence of PLC inhibitor, the fluorescent response of the sensor for PLC decreased, indicating that the assay could also be used for screening PLC inhibitors.