黄酮与溶菌酶相互作用的强度衰减-基质辅助激光解吸离子化-质谱研究

Interaction Studies of Lyszoyme and Flavonoids Using Intensity Fading-Matrix-assisted Laser Desorption/Ionization-Mass Spectrometry

建立了黄酮与溶菌酶相互作用研究的强度衰减-基质辅助激光解吸离子化-质谱(Intensity fading matrix-assisted laser desorption/ionization mass spectrometry,IF-MALDI-MS)分析方法。在优化的基质DHB条件下,分别研究了木犀草素、染料木素、芹菜素、槲皮素和大豆黄素与溶菌酶相互作用,比较了溶菌酶加入前后黄酮的相对丰度的变化,并通过竞争实验的方法研究了5种黄酮与溶菌酶结合的亲和性大小。结果表明,5种黄酮与溶菌酶均存在相互作用,亲和性强弱为:木犀草素>芹菜素,染料木素>槲皮素>大豆黄素。结合5种黄酮的结构特征,讨论了黄酮的结构及其与溶菌酶亲和性的关系,发现C5位和C3'位的羟基有利于黄酮与溶菌酶的结合,C3位的羟基不利于黄酮与溶菌酶的结合。本方法具有简便,快速,高效等优点,也可以应用于其它天然产物与蛋白质的相互作用的研究。

Flavonoids are reported to have a variety of biological activities. Investigations on the interactions of flavonoids with protein are essential to understand the biological activities of flavnoids. In this paper, by using the optimized matrix 2, 5-dihydroxybenzoic acid （DHB）, we investigated the interaction of five flavonoids （luteolin, apigenin, genisten, quercetin, dazein ） with lyszoyme using intensity fading （IF）- MALDI-MS method. The changes of relative abundances of flavonoids before and after addition of lyszoyme were calculated, and the binding affinity order was obtained by competitive experiments. It was found that all of the five flavonoids bound specifically to lysozyme. And the order of binding affinities of the five flavonoids to the lysozyme was luteolin〉apigenin, genisten〉quercetin〉dazein. Based on their structures, it was found that the hydroxyl on C5 and C3＇ benefited the binding of flavonoid towards lyszoyme. However, the hydroxyl on C3 hindered the binding of flavonoid towards lysozyme. The results should be helpful to understand the biological activity of flavonoids. And the IF-MALDI-MS method could also be used to screening the interactions of other natural products and protein.