4',5,7-三羟基二氢黄酮与人血清白蛋白相互作用的光谱学研究  

Spectroscopic Investigation of the Interaction between 2,3-Dihydro- 4',5,7-trihydroxyflavone and Human Serum Albumin

作　　者：谢孟峡[1] 徐晓云[1] 王英典[1] 刘媛[1] 

机构地区：[1]北京师范大学分析测试中心,北京100875

出　　处：《化学学报》2005年第22期2055-2062,共8页Acta Chimica Sinica

基　　金：国家自然科学基金(No.39970435);放射性药物教育部重点实验室开放基金资助项目.

摘　　要：应用紫外吸收光谱、荧光光谱和红外光谱等方法对人血清白蛋白(HSA)与4',5,7-三羟基二氢黄酮(naringenin,NAR)相互作用的机理进行了研究.紫外光谱显示,在生理pH下NAR分子中A环7位的酚羟基发生部分解离,7位酚羟基的解离使A环与B环上羰基形成的共轭体系的紫外吸收峰发生明显红移;药物与蛋白质的相互作用使该谱带发生了进一步的红移,说明该共轭体系参与了与蛋白质的相互作用.在药物与蛋白质浓度比(cNAR/cHSA)为0.1～10的范围内,NAR在HSA上只有一个结合位点(可能位于site I),结合常数为1.27×105L·mol^(-1)(n=5,RSD小于5%).研究了不同pH值条件下药物对蛋白质荧光猝灭的影响,发现药物分子中的没有解离的活性基团在结合过程中发挥着主导作用.在缓冲水溶液和重水溶液中分别测定了与药物作用前后蛋白质二级结构的变化.随着药物浓度的增加,NAR和HSA之间的相互作用使HSA的α-螺旋结构的含量明显降低,而β-折叠和β-转角结构的含量增加,无轨结构在药物浓度较高时也有少量的增加.结合紫外吸收光谱、荧光光谱和红外光谱结果,探讨了HSA与NAR相互作用的模式.The mechanism of interaction between 2,3-dihydro-4＇,5,7-trihydroxyflavone （naringenin, NAR） and human serum albumin （HSA） has been investigated by UV absorption, fluorescence and Fourier transform infrared spectroscopic methods. The UV absorption spectra revealed that the hydroxyl group at 7 position was partially dissociated at physiological pH （7.4） to cause significant red shift of UV absorption band originated from the conjugated system between the ring A and the carbonyl group of ring B. Further red shift of this band after interaction of NAR with human serum albumin signified that the conjugated system participated in the interaction. There was only one binding site （probably site I） in the drug to protein molar ratios ranging from 0.1 to 10, and the binding affinity was 1.27×10^5L·mol^-1 （n=5, RSD〈5%）. The effects of pH on the protein fluorescence quenching after interaction with NAR were studied to find that the active functional group in neutral state played key role in the binding process. The alterations of protein secondary structure before and after interaction with NAR were determined both in 1-120 and D20 buffer solutions. The percentage of protein a-helix structure was decreased with the increase of drug concentration, and that of fl-sheet and fl-turn structure increased. The content of random coil was also slightly increased in higher drug concentration. Combining the results of UV absorption, fluorescence and Fourier transform infrared spectroscooic methods, the binding mode of NAR with HSA was discussed.

关 键 词：4' 5 7-三羟基二氢黄酮 人血清白蛋白 傅立叶变换红外光谱 荧光光谱 紫外吸收光谱 蛋白相互作用 人血清白蛋白 二氢黄酮 三羟基 光谱学研究 蛋白质二级结构 紫外吸收光谱 药物浓度 α-螺旋结构 

分 类 号：R285[医药卫生—中药学]