State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China; School of Food Science and Technology, Nanchang University, Nanchang 330031, China.
State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China; Sino-German Joint Research Institute, Nanchang University, Nanchang 330047, China.
Int J Biol Macromol. 2018 Feb;107(Pt B):2057-2064. doi: 10.1016/j.ijbiomac.2017.10.072. Epub 2017 Oct 14.
Ovalbumin (OVA) is described as one of the major allergens in hen's egg, and it is the most abundant protein in egg white. Enzyme-mediated covalent cross-linking of food proteins, can influence their structure and allergenicity. The aim of this study was to investigate the potential of polyphenol oxidase from Agaricus bisporus to cross-link OVA (CL-OVA) in the presence or absence of caffeic acid, followed by characterizing the structure and allergenicity of CL-OVA. A single-factor experiment was designed to assess the optimum conditions for cross-linking of OVA by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Under the optimal conditions, structural changes in OVA were analyzed by circular dichroism, ultraviolet and fluorescence spectra. It was shown that CL-OVA became unordered and unfolded, and more tyrosine and tryptophan residues and hydrophobic groups were exposed onto the surface of molecules when compared to the native OVA. Enzyme-linked immunosorbent assay indicated that IgG and IgE binding abilities to OVA significantly reduced after cross-linking. All the findings demonstrated that enzymatic cross-linking in the presence of caffeic acid as a mediator may decrease the antigenicity and potential allergenicity, and the changes of the modified OVA were most likely a consequence of some changes or adjustment in the local conformation of OVA and the epitopes of OVA by cross-linking.
卵清蛋白（OVA）被描述为鸡蛋中的主要过敏原之一，也是蛋清中含量最丰富的蛋白质。酶介导的食物蛋白共价交联可以影响其结构和致敏性。本研究旨在研究双孢蘑菇多酚氧化酶在存在或不存在咖啡酸的情况下交联卵清蛋白（CL-OVA）的潜力，然后对 CL-OVA 的结构和致敏性进行表征。设计了单因素实验来评估 SDS-PAGE 交联 OVA 的最佳条件。在最佳条件下，通过圆二色性、紫外和荧光光谱分析 OVA 的结构变化。结果表明，CL-OVA 变得无序和展开，与天然 OVA 相比，更多的酪氨酸和色氨酸残基和疏水性基团暴露在分子表面。酶联免疫吸附试验表明，交联后 OVA 与 IgG 和 IgE 的结合能力显著降低。所有发现表明，在咖啡酸作为介体存在的情况下进行酶交联可能会降低抗原性和潜在致敏性，并且修饰后的 OVA 的变化很可能是由于 OVA 的局部构象的一些变化或调整以及 OVA 的表位通过交联。
