β-乳球蛋白、叶酸和视黄醇三元复合物的形成机制及功能性质  

Formation Mechanism and Functional Properties ofβ-Lactoglobulin-Folic Acid-Retinol Ternary Complexes

作　　者：包小妹 钟俊桢[1] 周若楠 周磊[1] 刘成梅[1] BAO Xiaomei;ZHONG Junzhen;ZHOU Ruonan;ZHOU Lei;LIU Chengmei(State Key Laboratory of Food Science and Technology,Nanchang University,Nanchang 330047,China)

机构地区：[1]南昌大学食品科学与技术国家重点实验室,江西南昌330047

出　　处：《食品科学》2020年第16期86-93,共8页Food Science

基　　金：南昌大学研究生创新专项(CX2018122);江西省自然科学基金面上项目(20181BAB204020)。

摘　　要：通过荧光光谱法、2,2’-联氮-双-3-乙基苯并噻唑啉-6-磺酸阳离子自由基清除能力测定法、1,1-二苯基-2-三硝基苯肼自由基清除能力测定法、铁离子还原/抗氧化能力法和间接ELISA法探究亲水性的叶酸(folic acid,FA)、疏水性的视黄醇(VA)与β-乳球蛋白(β-lactoglobulin,β-LG)三元复合物的形成机制及复合物的抗氧化性和致敏性变化。结果表明:FA和VA对β-LG具有较强的荧光猝灭,猝灭方式主要为静态猝灭。结合常数和结合位点数及热力学参数表明它们之间主要通过疏水相互作用形成结合常数(Ka)大于104 L/mol、物质的量比为1的较稳定的三元复合物。通过比较FA和VA不同添加顺序对β-LG荧光猝灭的程度可知,VA的存在会影响FA对β-LG的亲和性,而FA的存在不会影响VA对β-LG的亲和性。FA和VA单独与β-LG形成二元复合物时,与对照组相比抗氧化性没有显著性差异,当VA和FA共同与β-LG形成三元复合物时,抗氧化能力会高于二元复合物,但不同的结合顺序对复合物的抗氧化性没有显著影响。此外,β-LG-FA-VA致敏性抑制率降低为42.23%,β-LG-VA-FA致敏性抑制率增加为70.32%,由此可知不同的结合顺序会对β-LG的致敏性产生不同程度的影响。In our study,the formation mechanism of the ternary complex ofβ-lactoglobulin(β-LG)with folic acid(FA)as a hydrophilic molecule and retinol(VA)as a hydrophobic molecule was explored by fluorescence spectroscopy.The changes in the antioxidant activity and allergenicity ofβ-LG after complexation were examined by 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS)radical cation scavenging,1,1-diphenyl-2-picrylhdrazyl(DPPH)radical scavenging and ferric ion reducing antioxidant power(FRAP)assays as well as indirect enzyme-linked immunosorbent assay(ELISA),respectively.Fluorescence spectroscopy indicated that FA and VA had a strong ability to quench the fluorescence ofβ-LG mainly in a static mode.FA and VA could form stable ternary complexes withβ-LG through hydrophobic interaction,which was reflected by the binding constant(Ka)>104 L/mol,the number of binding sites ofβ-LG for FA and VA(about 1)and the thermodynamic parameters.The presence of VA affected the affinity of FA forβ-LG,while the presence of FA did not affect the affinity of VA forβ-LG.The results of ABTS,DPPH and FRAP assays showed that the antioxidant activity ofβ-LG-FA andβ-LG-VA was not significantly different compared with that ofβ-LG,but lower than that ofβ-LG-FA-VA.Different binding sequences had no significant effect on the antioxidant activity of the ternary complex.Indirect competitive ELISA showed thatβ-LG-FA-VA gave a lower inhibition of 42.23%againstβ-LG antigenicity,whileβ-LG-VA-FA exhibited a higher inhibition of 70.32%.These results indicate that different binding sequences had different effects on the antigenicity ofβ-LG.

关 键 词：Β-乳球蛋白 叶酸 视黄醇 多元复合物 抗氧化性 致敏性 

分 类 号：TS201.2[轻工技术与工程—食品科学]