超声波处理对β-乳球蛋白结构和抗原性的影响

Effect of ultrasound treatment on structure and antigenicity of β- lactoglobulin

采用电泳、圆二色谱、荧光光谱及酶联免疫吸附等方法,研究了超声波处理对β-乳球蛋白(β-lactoglobulin,β-Lg)结构和抗原性的影响。结果表明:随着超声波功率的增大,β-Lg的分子量无显著性变化,自由巯基含量下降,β-折叠含量和表面疏水性呈先升高后降低的趋势,且均在400 W时达到最大值。这表明超声波处理能迫使β-Lg结构展开,破坏其高级结构。与此同时,β-Lg的抗原性呈先升高后降低的趋势,在400 W 25 min时达到最大,为2540.20μg/m L,比未处理样品增加了133%,这表明β-Lg结构的展开可能会导致其过敏表位的暴露,因此,β-Lg抗原性的改变可能与其高级结构的变化有关。

In order to study the effect of ultrasound treatment on structure and antigenicity of β-lactoglobulin （β-Lg）, SDS-PAGE, circular dichroism spectra, fluorescence spectrum and indirect competitive enzyme-linked immunosorbent assay were used to measure the structure and antigenicity, respectively.The molecular weight of β-Lg was not significant change, free sulfhydryl groups decreased, the content of β- sheet and surface hydrophobicity firstly increased and then decreased with the increasing of ultrasonic power.The content of β-sheet and surface hydrophobicity reached the maximum with 400 W ultrasound treatment. It was indicated that β-Lg could be unfolded and spacial structure was destroyed by ultrasound treatment. Meanwhile, the antigenicity of β-Lg was also firstly increased and then decreased.When it was treated at 400 W for 25 min,the antigenicity of β-Lg increased up to 2540.20 μg/mL, showing an increase by 133%.The results indicated that the unfolding of β-Lg might result in the allergic epitope exposed.Therefore,the antigenicity change of β-Lg was probably related to its spacial structural alteration induced by ultrasound treatment.