左旋紫草素与溶菌酶相互作用的研究  

Interaction between Shikonin and Lysozyme

作　　者：李玉琴[1] 贾宝秀[1] 冀海伟[1] 郭丰广[1] 齐永秀[1] 

机构地区：[1]泰山医学院药学院,山东泰安271016

出　　处：《分析测试学报》2009年第5期544-549,共6页Journal of Instrumental Analysis

基　　金：泰山医学院博士启动基金资助项目(2006742)

摘　　要：利用荧光猝灭方法结合紫外光谱(UV)、傅立叶红外光谱(FT-IR)和圆二色性光谱(CD),在模拟生理条件下研究了左旋紫草素和溶菌酶的结合常数、主要作用力以及左旋紫草素对溶菌酶二级结构的影响。在温度为296、303和310K时,根据Scatchard方程测得左旋紫草素和溶菌酶的结合常数分别为3.022×104、1.894×104、0.9581×104L.mol-1,结合位点数分别为0.98、0.76、0.68;焓变(ΔH)和熵变(ΔS)分别为-14.78kJ/mol、24.26J/(mol.K),结果表明其主要作用力为疏水性和静电作用力。同步荧光和紫外光谱研究进一步证明左旋紫草素与溶菌酶有着较强的结合,左旋紫草素对溶菌酶的荧光猝灭为多种机理同时存在,并根据Frster能量非辐射转移理论测得结合位置与色氨酸残基间的距离r为4.62nm。CD和FT-IR研究显示,左旋紫草素使溶菌酶的二级结构发生了变化。该文为左旋紫草素在人体内的储存、运输、作用机理及临床试验提供了具有指导作用的信息。The binding constants, major force modes between shikonin and lysozyme （LYSO）, and secondary changes of LYSO under simulated physiological conditions were investigated by means of fluorescence quenching methods combined with ultraviolet -visible （UV）, Fourier transform infrared spectrum（FT- IR） and circular dichroism（CD） spectra. Based on Scatchard equation, the binding constants（K） at 296, 303 and 310 K were calculated to be 3. 022 ×10^4, 1. 894 ×10^4, 0. 958 1 ×10^4L · mol-1, respectively, and the binding sites（n） were 0. 98, 0. 76, 0. 68, respectively. The enthalpy change（AH） and the entropy change（AS） were - 14.78 kJ/mol and 24.26 J/（mol · K）, respectively. Results indicated that hydrophobic and electrostatic forces played major role in the inter- action of shikonin and LYSO. Furthermore, the synchronous fluorescence and UV spectra indicated that shikonin bound to LYSO with high binding force, and the quenching reactions were resulted by the several reaction mechanisms between shikonin and LYSO, and the distance between shikonin and LYSO was 4.62 nm based on Forster＇s theory of non-radiation energy transfer. The results of CD and FT - IR spectra indicated that the secondary structure of protein was changed when shikonin bound to LYSO, in which a-helix content of LYSO increased from 12.0% to 27.8%. This study could pro- vide some direct information to the transportation, mechanism and clinical experiments of the shikonin in vivo.

关 键 词：左旋紫草素 溶菌酶 相互作用 荧光光谱 紫外光谱 傅立叶红外光谱 圆二色谱 

分 类 号：O657.3[理学—分析化学] TQ932[理学—化学]