热加工对花生过敏原Ara h2抗原性及构象的影响

Effect of Heat Treatment on the Antigenicity and Conformation of Peanut Allergen Ara h 2

从花生种子中分离纯化花生过敏原Ara h 2,采用酶联免疫吸附试验(ELISA)、圆二色谱(CD)、ANS荧光探针及紫外可见(UV-Vis)光谱等方法,系统研究热加工对Ara h 2抗原性和结构的影响。结果表明:Ara h 2蛋白经55或70℃处理后其抗原性略有升高,经85,100或115℃处理后,其抗原性显著降低,且随着温度和时间的增加其抗原性均不断降低。CD色谱分析表明,Ara h 2经热处理后其二级结构发生变化;ANS荧光探针光谱显示,不同的热处理均导致Ara h 2表面疏水性增加。紫外光谱显示,不同温度对Ara h 2处理30 min后(除55℃外),其紫外吸收值均升高。Ara h 2经100℃处理不同时间后,其紫外吸收值均有增加。由此推断,花生过敏原Ara h 2的构象改变导致了其抗原性的降低。

Peanut allergen Ara h 2 was extracted from peanuts and was identified by SDS-PAGE and MALDI-TOF-MS.Effect of heat treatment on the antigenicity and structure of Ara h 2 was measured by indirect ELISA,CD,fluorescence and UV absorption spectra.The results showed that the antigenicity of Ara h 2 had a slight increase after being heated at 55 or 70 ℃,while above 85 ℃ the antigenicity decreased significantly,and the antigeicity of Ara h 2 decreased with increasing temperature.The CD showed that the secondary structure of Ara h 2 was changed after heat treatment.The ANS fluorescence probe emission spectra analysis demonstrated that the heat treatment induced an increase in surface hydrophobicity of Ara h 2.The UV absorption spectra showed that the absorption maximum wavelength was increased when Ara h 2 was heated except the sample heating at 50 ℃ for 30 min.So the changes in conformation of Ara h 2 lead to the antigenicity degression.