牛α-乳白蛋白-亚油酸复合物的结构及抗肿瘤活性

发布时间：2018-12-14 00:44

【摘要】：利用内源性荧光光谱、荧光探针(ANS)结合荧光光谱及圆二色谱,以乳白蛋白-油酸为参照,研究了乳白蛋白结合亚油酸后,疏水性氨基酸、疏水性区域、三级结构及二级结构的变化,并利用亚甲基蓝的方法评价了该复合物的抗肿瘤活性。荧光光谱结果显示,与乳白蛋白-油酸复合物类似,乳白蛋白结合亚油酸后,其内源性荧光光谱显著红移,从331.07nm移至337.60nm;外源性ANS结合光谱蓝移,从516.20nm移至508.50nm;且荧光强度增加,表明乳白蛋白结合亚油酸后同样出现了疏水性氨基酸及疏水性区域暴露的现象。圆二色谱结果表明,与乳白蛋白-油酸复合物类似,乳白蛋白结合亚油酸后,三级结构部分丧失,二级结构中β-转角及无规卷曲的含量显著降低,β-折叠含量增加。细胞实验证实了乳白蛋白-亚油酸复合物具有良好的抗肿瘤效果。该研究从复合物结构和功能的两方面,为新型抗肿瘤乳白蛋白-亚油酸复合物的开发提供了依据。
[Abstract]:The hydrophobic amino acids and hydrophobic regions of lactalbumin binding linoleic acid were studied by using endogenous fluorescence spectrum, fluorescence probe (ANS) binding fluorescence spectrum and circular dichroism, with lactoalbumin oleic acid as reference. The antitumor activity of the complex was evaluated by methylene blue method. The fluorescence spectra showed that, similar to the lactoalbumin-oleic acid complex, the endogenous fluorescence spectra of lactalbumin bound linoleic acid shifted significantly from 331.07nm to 337.60 nm. The blue shift of exogenous ANS binding spectrum from 516.20nm to 508.50 nm, and the increase of fluorescence intensity, indicated that hydrophobic amino acids and hydrophobic region exposures also appeared after the binding of lactalbumin to linoleic acid. The results of circular dichroism showed that, similar to lactoalbumin-oleic acid complex, the tertiary structure was partially lost after lactalbumin binding to linoleic acid, the 尾 -rotation angle and the content of random coil in the secondary structure decreased significantly, and the content of 尾 -fold increased. Cell experiments confirmed that lactoalbumin-linoleic acid complex had a good anti-tumor effect. This study provides a basis for the development of a novel anti-tumor lactoalbumin-linoleic acid complex in terms of its structure and function.
【作者单位】：北京工商大学食品学院;国家粮食局科学研究院;中国农业大学教育部-北京市共建功能乳品重点实验室;
【基金】：国家科技支撑计划项目(2012BAD12B08) 国家国际科技合作专项(2011DFA32550)资助
【分类号】：R914;R96

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