圆二色光谱法研究酸度、槲皮素、锌离子对β-酪蛋白二级结构的影响.PDF

2010 年第68 卷 化 学 学 报 Vol. 68, 2010 第14 期, 1449～1453 ACTA CHIMICA SINICA No. 14, 1449～1453 ·研究论文· 圆二色光谱法研究酸度、槲皮素、锌离子对β-酪蛋白二级结构的影响 吕鉴泉*,a 王雪梅a 吕桂英b 孙婷荃a 唐金燕a 徐明波a a ( 湖北师范学院 污染物分析与资源化技术湖北省重点实验室 黄石 435002) (b 黄石理工学院化学与材料工程学院 黄石 435003) 摘要 采用圆二色光谱(CD)技术研究了酸度、槲皮素(Qct)和锌离子对溶液中β-酪蛋白(β-CN)二级结构的影响. 结果表 明, 酸度、Qct 和锌离子均能够诱导β-CN 二级结构发生改变. 在pH 7.6 的条件下, β-CN 各种结构分别为32.6% α-螺旋, 53.5% β-折叠, 13.9% γ-转角和无规卷曲; Qct 使β-CN 的α-螺旋含量增加、β-折叠含量减少; 锌离子和Zn-Qct 配合物导 致β-CN 的α-螺旋含量大幅度降低, β-折叠含量略有增加, 同时转角和无规的含量也大幅度增加. 关键词 二级结构; β-酪蛋白; 圆二色光谱; 槲皮素; 锌离子 Effect of pH, Quercetin and Zinc Ion on the Structure of β-Casein by Circular Dichroism Method Lü, Jianquan*,a Wang, Xuemeia Lü, Guiyingb Sun, Tingquana Tang, Jinyana Xu, Mingboa a ( Hubei Key Laboratory of Pollutant Analysis Reuse Technology, Hubei Normal University, Huangshi 435002) (b School of Chemical and Material Engineering, Huangshi Institute of Technology, Huangshi 435003) Abstract The effect of pH, quercetin (Qct) and Zn(II) on the structure of β-casein (β-CN) in solution were investigated using circular dichroism spectroscopy. The results indicated that the secondary structures of β-CN in the solution were induced by the pH, quercetin and Zn(II)-Qct complexes. In pH 7.6 PBS buffer, β-CN contain 32.6% α-helix, 53.5% β-sheet and 13.9% γ-turn and random coil, the addition of Qct cause in- crease the content of α-h