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1、槲皮素与人血清白蛋白作用机理王欢，王姣，蒲小华，李宗孝*（陕西省植物化学重点实验室，陕西宝鸡721013）摘要:采用荧光光谱、紫外吸收光谱、分子模拟等技术，研究了槲皮素与人血清白蛋白(HSA)相互作用的热力学行为。荧光实验结果表明：槲皮素与HSA相互作用时，随着槲皮素的浓度从0增加到19.62×10-7mol/L，HAS的荧光强度从844.3下降到461.4，最大发射波长由340.7nm降低到338.6nm，变化不明显，并且随着温度从298K升高到303K，猝灭常数由4.66×105L/mol减小到2.69×105L/mol，说明槲皮素对HSA的内源荧光有明显的猝灭作用，猝灭机理为静态猝灭。分
2、子模拟结果显示：槲皮素分子在HAS的SudlowI位点和SudlowII位点的结合最高积分别为6.41和7.36，总能量分别为-37.01kJ/mol和-39.98kJ/mol，表明其在SudlowII位点的结合能力较强，且两种结合的作用力主要为氢键作用（键能分别为-10.41kJ/mol和-12.34kJ/mol）。在位点I和位点II上，槲皮素分子与发光氨基酸残基Trp214的质心距离分别为1.36和2.40nm。这与根据Förster’s非辐射能量转移理论计算的平均距离3.04nm结果基本吻合。关键词：人血清白蛋白；荧光光谱；分子模拟技术；槲皮素；静态猝灭中图分类号：O657.3文献标识码
3、：AStudyontheMechanismbetweenQuercetinandHumanserumalbuminWANGHuan,WANGJiao,PUXiao-hua,LIZong-xiao*(ShannxiKeyLaboratoryofPhytochemistry, Baoji,Shaanxi721013, China)Abstract:ThethermodynamicbehavioroftheinteractionbetweenQuercetinandHSAisinvestigatedbyFS,UVSandMS.Influorescenceexperiments,Theinteract
4、ionofquercetinandHSA,withC(quercetin)increasedfrom0to19.62×10-7mol/L,thefluorescenceintensityofHASdecreasedfrom844.3to461.4,themaximumemissionwavelengthfrom340.7nmto338.6nm,didnotchangesignificantly,andasthetemperatureincreasesfrom298Kto303K,thequenchingconstantdecreasesfrom4.66×105L/molto2.69×105L/
5、molthefluorescenceintensityofHSAobviouslydecreaseswiththeincreaseofquercetinconcentration,butthemaximumemissionwavelengthhasnoobviousdisplacement,andthequenchingconstantdecreaseswiththeraisingoftemperature.TheresultsshowthatquercetincanstronglyquenchintrinsicfluorescenceofHSAandquenchingmechanismofq
6、uercetinwithHSAismainlyastaticquenching.Inmolecularsimulationexperiments,thequercetinmoleculeonSudlow’ssitesIandSudlow’ssitesIIwiththehighestpointare6.41and7.36,inatotalenergyof-37.01kJ/moland-39.98kJ/molrespectively,showstrongerbindingonsiteIIandhydrogenbondinginteractionsarethemajorforces(bondener
7、giesare-10.41kJ/moland-12.34kJ/molrespectively).AndonthesiteIandsiteII,thedistancesfromquercetintothecenterpositionoffluorescentaminoacidresiduesTrp214are1.36and2.40nm,whichareinagreementwiththedistan
