大豆蛋白-木糖复合物的抗原性、致敏性及结构特性研究

Antigenicity, Allergenicity, and Structural Properties of Soy Protein Isolate-Xylose Conjugates

摘要:

大豆是营养丰富的植物蛋白资源，但也是八大过敏原之一；糖基化修饰是一种降低食物过敏原的有效方法。本文将木糖通过糖基化的方法引入大豆分离蛋白制备大豆分离蛋白-木糖复合物，采用间接竞争ELISA法，测定在一定温度、一定质量比、不同反应时间条件下，大豆分离蛋白-木糖复合物中大豆球蛋白的抗原性和过敏原性的变化，并且对糖基化产物进行了结构特性的研究。结果表明，糖基化能有效降低大豆球蛋白的抗原性和过敏原性，其抗原性从83.01%降到67.43%；过敏原性从46.32%降低到29.48%；两者在反应10 h时免疫活性都较低。通过三硝基苯磺酸(TNBS)法、SDS-PAGE电泳证明了糖基化反应的发生；傅里叶红外光谱结果表明，与大豆分离蛋白相比，SPI-木糖糖基化产物的α-螺旋、β-转角的含量下降，而无规卷曲、β-折叠的含量增加。

Abstract:

Soybean is a high-quality plant protein source, but it is also one of the top eight food allergens. Glycosylation is an effective method to reduce the allergenic potential of food protein allergens. Xylose was conjugated to soy protein isolate (SPI) by means of glycosylation to form SPI-xylose conjugates. The changes in the antigenicity and allergenicity of glycinin in SPI-xylose conjugates at a specific temperature, specific mass ratio of the protein and sugar, and different reaction times were determined by the indirect competitive enzyme-linked immunosorbent assay, and the structural properties of SPI-xylose conjugates were also studied. The results indicate that glycosylation can effectively reduce the antigenicity and allergenicity of glycinin. The antigenicity of glycinin was reduced from 83.01% to 67.43%; the allergenicity of glycinin was reduced from 46.32% to 29.48%, and both immunoreactivities were relatively low after ten hours of reaction. Glycosylation was confirmed by trinitrobenzene sulfonic acid and sodium dodecyl sulfate polyacrylamide gel electrophoresis. The Fourier transform infrared spectroscopy results showed that compared with SPI, the α-helix and β-turn content in SPI-xylose conjugates decreased, while the β-sheet and random coil contents increased.