荧光法研究3种甲基黄嘌呤类生物碱与牛血清白蛋白的相互作用  

Study on the Interaction between 3 Kinds of Methylxanthine Alkaloids and Bovine Serum Albumin by Fluorescence Spectrometry

作　　者：谢宝平[1] 邢惟青[1] 丘玉昌[1] 曹莹[1] 庞建新[1] 

机构地区：[1]南方医科大学药学院,广州市510515

出　　处：《中国药房》2011年第37期3497-3500,共4页China Pharmacy

摘　　要：目的:研究咖啡因、茶碱、可可碱3种甲基黄嘌呤类生物碱与牛血清白蛋白(BSA)结合反应的荧光光谱行为,了解其与蛋白质结合的信息。方法:采用荧光光谱法研究25℃和37℃时3种生物碱不同浓度对BSA的荧光猝灭作用,通过Stern-Volmer曲线和Perrin曲线线性拟合计算得到动态猝灭常数和静态猝灭常数,判断猝灭机制;计算结合常数、结合位点数及热力学函数ΔH、ΔS、ΔG,判断其结合作用力模型。结果:随着3种生物碱浓度升高,BSA内源荧光强度有规律地降低;随温度的升高,静态猝灭常数和结合常数均降低,而3种生物碱与BSA的结合常数差别较大,但结合位点数均接近1;ΔG<0,ΔH<0,ΔS>0。结论:3种生物碱能较显著猝灭BSA的荧光,且机制均为静态猝灭,与白蛋白之间均存在以疏水相互作用为主的结合作用;3种结构相近的生物碱与BSA的相互作用存在差异。OBJECTIVE： To study the spectrum characteristic of the association reaction between bovine serum albumin （BSA） and 3 kinds of methylxanthine alkaloids including caffeine, theophylline, theobromine, and to understand the association information between them and protein. METHODS ： Fluorescence spectroscopy technique was used to investigate the interactions of 3 kinds of alkaloids and BSA at 25℃ and 37 ℃, and dynamic quenching constant and static quenching constant were calculated by using Stern-Volmer curves and Perrin curves to determine quenching mechanism. The binding constant and number of binding site were obtained as well as thermodynamic function △H, △S,△G. The interaction model was determined. RESULTS： With 3 kinds of alkaloids increased, endogenous fluorescence intensity of BSA decreased regularly. The static quenching constants and binding constants all decreased while binding constants of 3 kinds of alkaloids with BSA had significant difference. The numbers of binding sites were approximately equal to 1. Thermodynamic function △H was lower than 0 while both of △S and △G were higher than 0. CONCLUSION： Fluorescence quenching of BSA is induced by 3 kinds of alkaloids with static quenching mechanism. The interactions between 3 kinds of methylxanthine alkaloids and albumin mainly are hydrophobic interaction. There are differences among interactions between BSA and 3 kinds of alkaloids which have similar structure.

关 键 词：甲基黄嘌呤类生物碱 咖啡因 茶碱 可可碱 荧光光谱 牛血清白蛋白 相互作用 

分 类 号：R913[医药卫生—药学]