啤酒泡沫蛋白质的二级结构特点及其质谱鉴定

摘要

泡沫蛋白质对啤酒泡沫性能有重要影响.采用圆二色光谱技术研究啤酒泡沫蛋白质和麦芽蛋白质的二级结构构象特点,通过SDS-聚丙烯酰胺凝胶电泳(1D SDS-PAGE)与液质(LC-MS/MS)联用对啤酒泡沫蛋白质进行分离与鉴定.结果显示,麦芽蛋白质以α-螺旋结构为主,而啤酒泡沫蛋白质以β-折叠和无规则卷曲为主,并未表现出典型的α-螺旋双负峰特征,这种结构有利于泡沫蛋白质的疏水性,从而有利于啤酒泡沫的稳定性.经质谱检测,啤酒泡沫蛋白质中共鉴定出11种蛋白质,包括蛋白质Z4、LTP1、BDAI-1及部分酶抑制剂和少量醇溶蛋白片段.%Beer foam proteins play important roles on beer foam quality. In this study,the secondary structure of beer foam proteins and malt proteins were investigated by Circular Dichroism spectroscopy,and SDS-PAGE pre-fractionation combined with LC-MS/MS was applied to achieve more comprehensive proteome profiles of beer foam proteins. It was indicated that malt proteins mainly existed in a-helix form,while beer foam proteins mainly existed in β-sheet and random coil structure,not showing the typical a -helix structure. The structure characteristic of foam proteins had the advantage to the surface hydrophobic,so as to the beer foam stability. Beer protein bands were positively identified and categorized into 11 protein species,which included protein Z4,LTP1,BDAI-1,and some proteinase inhibitors and trace amount hordein fragments.