A novel fluorescence sensor for milk clotting enzyme chymosin using peptide as substrate and covalent organic framework nanosheet as fluorescence quencher  

作　　者：Xiaokang Lu Tianle Qi Linjiang Guo Lin Xiao Hanbin Xu Guobao Ning Hui Zhao Canpeng Li 

机构地区：[1]School of Chemical Science and Technology,Yunnan University,Kunming 650091,China [2]Laboratory for Conservation and Utilization of Bio-Resource,Yunnan University,Kunming 650091,China

出　　处：《Food Science and Human Wellness》2024年第6期3606-3613,共8页食品科学与人类健康（英文）

基　　金：supported by Major Science and Technology Project of Yunnan Province(202302AE090022);Key Research and Development Program of Yunnan(202203AC100010);the National Natural Science Foundation of China(32160597,32160236,32371463);National Key Research and Development Program of China(2022YFC2601604);Cardiovascular Ultrasound Innovation Team of Yunnan Province(202305AS350021);Spring City Plan:the High-Level Talent Promotion and Training Project of Kunming(2022SCP001);Graduate Tutor Team of Yunnan Province,and the Second Phase of"Double-First Class"Program Construction of Yunnan University.

摘　　要：Chymosin is one of the critical enzymes in cheese making.Herein,we proposed a novel fluorometric assay for chymosin determination.Firstly,covalent organic frameworks(COF)were synthesized and exfoliated to 2-dimensional COF nanosheets(COF NS)by ultrasound treatment.Gold nanoparticles(Au NPs)were loaded with COF NS to prepare AuNPs/COF NS(Au@COF NS).Secondly,rhodamine B(RhB)modified substrate peptide(Pep)for chymosin was linked with Au@COF NS to construct a Pep-Au@COF NS nanocomposite.For the sensing principle,fluorescence of RhB was quenched by Au@COF NS and the fluorescence intensity was weak due to the fluorescence resonance energy transfer between COF NS and RhB of Pep.However,in the presence of chymosin,the RhB was released by specific cleavage of the substrate peptide by chymosin and resulted in the recovery of fluorescence.The increased fluorescence intensity was proportional to the increase of chymosin concentration and thus a“turn on”fluorescent sensor for chymosin was constructed.The sensor showed a linear range in the concentration of 0.05-60.00μg/mL for the detection of chymosin with a detection limit of 20 ng/mL.The sensor was used to quantify chymosin in rennet product with good selectivity,which has the potential applications in cheese manufacturing.

关 键 词：Covalent organic framework Fluorescence sensor CHYMOSIN Fluorescence resonance energy transfer 

分 类 号：TS252.53[轻工技术与工程—农产品加工及贮藏工程] O657.3[轻工技术与工程—食品科学与工程]