温压结合的超高压技术对虾原肌球蛋白抗原性与结构的影响

Effect of High Hydrostatic Pressure Combined with Temperature on the Antigenicity and Conformation of Tropomyosin Purified from Shrimp

近年来食源性虾过敏的事件时有发生。为深入研究超高压技术改变虾类致敏性的机理,从凡纳滨对虾中分离纯化出最主要过敏原原肌球蛋白,利用基质辅助激光解吸电离飞行时间质谱(MALDI-TOF-MS)对原肌球蛋白进行了鉴定,并运用间接酶联免疫吸附法(间接ELISA)和圆二色光谱法(CD)以及荧光光谱法分析了温压结合的超高压技术中温度因素对原肌球蛋白抗原性与结构的影响。结果表明,原肌球蛋白在300MPa 15min处理条件下,经35与45℃处理,其抗原性增强,而经55,65与75℃处理,其抗原性降低。原肌球蛋白二级结构随温度上升,出现α-螺旋与β-折叠、β-转角以及无规则卷曲结构之间的转换;三级结构发生了由伸展状态到折叠状态,再有部分伸展而后折叠的动态变化。由此推断,温压结合的超高压技术中通过调节温度条件,可引起虾原肌球蛋白构象发生变化,进而影响其抗原性的改变。研究结果对于开发低敏性虾制品的新方法、新工艺具有理论指导意义。

Foodborne shrimp allergy events have occurred in recent years.To illustrate the mechanism of high hydrostatic pressure technology to change the allergenicity of shrimp,the major allergen tropomyosin was separated and purified fromLitopenaeus vannamei,and indentified with matrix assisted laser desorption ionization time of flight mass spectrometry（MALDI-TOFMS）.The effect of temperature factor under high hydrostatic pressure was measured with indirect ELISA method,CD and fluorescence spectrum.The results showed that the antigenicity of TM protein had an increase after being heated at 35 or 45℃ when treated at 300 MPa for 15 minutes,while the antigenicity decreased at 55,65,and 75℃.With the increase of heat temperature,the secondary structure of TM also changed.The mutual transformation happened between the alpha-helix and beta-sheet,betaturn,and the random coil.The tertiary structure of TM was observed dynamic changes from the extended state to the folded state,and then re-extended state to re-folded state.These results suggested that high hydrostatic pressure combined with temperature could influence the antigenicity of TM by the change of conformation which would be useful as theoretical guidance on developing new methods or technologies for producing hypoallergenic shrimp products.