CAJ | 학술논문

在pH 7.4的Tris-HCl的缓冲溶液中,采用紫外及荧光光谱法研究了荷叶中紫云英苷(AST)与DNA之间的相互作用,探讨了离子强度和阴离子猝灭剂KI对紫云英苷及紫云英苷-DNA体系荧光强度的影响,同时考察了紫云英苷和中性红与DNA结合的竞争性.结果表明DNA通过静态猝灭作用机制猝灭紫云英苷的荧光,并测得其在298及308 K时的猝灭速率常数(K_q)分别为3.120×10~(12)和2.630×10~(12) L·mol~(-1)·s~(-1),结合常数(K_d)分别为3.412×10~4和1.762×10~4 L·mol~(-1),结合位点数(n)分别为1.007和0.962;DNA的存在使紫云英苷的紫外吸收光谱发生减色效应且吸收波长产生红移;发现离子强度的改变对紫云英苷及紫云英苷-DNA体系的荧光强度影响不大;KI对结合形式存在的紫云英苷的荧光猝灭效率明显小于自由形式存在的紫云英苷的荧光猝灭效率;紫云英苷可插入DNA中置换出与DNA结合的中性红.这些结果说明倚叶中紫云英苷以嵌插模式与DNA进行结合.
재pH 7.4적Tris-HCl적완충용액중,채용자외급형광광보법연구료하협중자운영감(AST)여DNA지간적상호작용,탐토료리자강도화음리자졸멸제KI대자운영감급자운영감-DNA체계형광강도적영향,동시고찰료자운영감화중성홍여DNA결합적경쟁성.결과표명DNA통과정태졸멸작용궤제졸멸자운영감적형광,병측득기재298급308 K시적졸멸속솔상수(K_q)분별위3.120×10~(12)화2.630×10~(12) L·mol~(-1)·s~(-1),결합상수(K_d)분별위3.412×10~4화1.762×10~4 L·mol~(-1),결합위점수(n)분별위1.007화0.962;DNA적존재사자운영감적자외흡수광보발생감색효응차흡수파장산생홍이;발현리자강도적개변대자운영감급자운영감-DNA체계적형광강도영향불대;KI대결합형식존재적자운영감적형광졸멸효솔명현소우자유형식존재적자운영감적형광졸멸효솔;자운영감가삽입DNA중치환출여DNA결합적중성홍.저사결과설명의협중자운영감이감삽모식여DNA진행결합.
The interaction between astragalin(AST)from lotus leaf and deoxyribonucleic acid(DNA)in Tris-HCl buffer(pH=7.4)was investigated by the application of fluorescence spectroscopy and ultraviolet absorption spectroscopy,the effects of ionic 'strength and anion quencher KI on the fluorescence intensity of AST from lotus leaf and the system of AST-DNA were explored,and the competitive binding to DNA between AST from lotus leaf and Neutral Red(NR)dye was also studied.The results demonstrated that AST could bind to DNA and the formed complex quenched the intrinsic fluorescence of AST from lotus leaf through static quenching mechanism.The quenching rate constants of biomolecule(K_q)of the reaction of DNA with AST from lotus leaf were calculated to be 3.120×10~(12) and 2.630×10~(12) L·mol~(-1)·s~(-1) by Stern-Volumer equation,the corresponding binding constants(K_d)were computed to be 3.412×10~4 and 1.762×10~4 L·mol~(-1) and the number of binding sites(n)was counted to be 1.007 and 0.962 between AST from lotus leaf and DNA at 298 and 308 K,respectively.When bound to DNA,the AST from lotus leaf showed hypochromic effect and red shift in the absorption spectra.It was also found that different ionic strength had little or no effect on the fluorescence intensity of AST and AST-DNA,but the fluorescence intensity of AST-DNA qtienched by anionic quencher KI was much less than that of free AST.AST could be intercalated into DNA and displaced the NR from the NR-DNA complex.It was showed that AST from lotus leaf could combine with DNA in the mode of intercalation.