摘要
以β-乳球蛋白(β-lactoglobulin,β-LG)为对象,探究膳食多酚迷迭香酸(rosmarinic acid,RA)共价偶联对蛋白结构和性质的影响。采用自由基法和碱法制得β-LG-RA共价偶联复合物;利用十二烷基硫酸钠-聚丙烯酰胺凝胶电泳、傅里叶变换红外光谱、紫外吸收光谱、荧光光谱、圆二色光谱等技术,分析RA共价偶联后β-LG结构变化规律;通过对1,1-二苯基-2-三硝基苯肼自由基和2,2’-联氮双(3-乙基苯并噻唑啉-6-磺酸)阳离子自由基清除率检测及酶联免疫吸附测试,评价β-LG与RA共价偶联前后抗氧化性和与血清特异性免疫球蛋白G(immunoglobulin G,IgG)结合能力的变化。结果表明:RA共价偶联后β-LG的二级结构由α-螺旋向β-折叠和无规卷曲转变,蛋白的二、三级结构发生改变。此外,与β-LG相比,β-LG-RA共价偶联复合物的抗氧化性显著增强,与血清特异性Ig G的结合能力显著减弱。综上,RA共价偶联通过引入酚羟基增强了蛋白的抗氧化性,改变了β-LG的结构,降低了其与血清特异性IgG的结合能力。
The present study aimed to investigate the effect of covalent coupling with the dietary polyphenol rosmarinic acid(RA)on the structure and properties ofβ-lactoglobulin(β-LG).β-LG-RA complexes were prepared using the free radical and alkaline methods.The structural changes ofβ-LG after coupling with RA were analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE),Fourier transform infrared(FTIR)spectroscopy,ultraviolet(UV)absorption spectroscopy,fluorescence spectroscopy,and circular dichroism(CD)spectroscopy.The antioxidant activity of β-LG and its complexes with RA was assessed using the 1,1-diphenyl-2-picrylhydrazyl(DPPH)radical and 2,2’-azino-bis 3-ethylbenzothiazoline-6-sulfonic acid(ABTS)radical cation scavenging methods.Furthermore,their binding capacity to serum-specific immunoglobulin G(IgG)were evaluated using enzyme-linked immunosorbent assay(ELISA).The results revealed that the secondary structure ofβ-LG transformed fromα-helix toβ-sheet and random coil after RA covalent conjugation.The protein underwent changes in its secondary and tertiary structures.Additionally,compared toβ-LG,theβ-LG-RA covalent conjugates showed significantly enhanced antioxidant activity and reduced binding ability with serum specific IgG.In conclusion,covalent coupling with RA led to a significant improvement in the antioxidant activity ofβ-LG and a significant decrease in its binding capacity to serum-specific IgG by introducing phenolic hydroxyl groups.
作者
杨庆
尚洁丽
曾浩龙
王璇霈
陈义杰
柳鑫
宫智勇
许琳
YANG Qing;SHANG Jieli;ZENG Haolong;WANG Xuanpei;CHEN Yijie;LIU Xin;GONG Zhiyong;XU Lin(Wuhan Polytechnic University,Key Laboratory for Deep Processing of Major and Oil,Ministry of Education,Wuhan 430023,China;Tongji Hospital,Tongji Medical College,Huazhong University of Science and Technology,Wuhan 430030,China;College of Food Science and Technology,Huazhong Agriculture University,Wuhan 430070,China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2024年第11期61-67,共7页
Food Science
基金
大宗粮油精深加工教育部重点实验室开放课题项目(NJZ2022009)。
关键词
Β-乳球蛋白
迷迭香酸
共价偶联
蛋白结构
蛋白性质
β-lactoglobulin
rosmarinic acid
covalent conjugation
protein structure
protein properties
