荧光猝灭法研究8-烷基黄连碱衍生物对溶菌酶的作用机制

Study on the binding interaction of 8-alkyl coptisine derivatives with lysozyme by fluorescence quenching method

通过测定不同温度(12、24、36℃)下8-烷基黄连碱衍生物(Cop-C8-n,n=4、6、8)对溶菌酶的荧光猝灭常数,并计算热力学参数,研究8-烷基黄连碱衍生物对溶菌酶的作用机制。结果表明:8-烷基黄连碱衍生物对溶菌酶的内源性荧光可产生极强的猝灭作用,猝灭作用过程既有静态猝灭又有动态猝灭;热力学参数证明,黄连碱衍生物与溶菌酶的结合作用力主要为疏水作用力,随着烷基链的增长,溶菌酶的紫外吸收逐渐下降;在荧光分析中,24℃下溶菌酶与Cop-C8-8的结合位点为2,结合常数为2.063×107,都显著高于Cop-C8-6和Cop-C8-4。

Interaction between 8-alkyl coptisine derivatives and lysozyme were investigated by measuring the quenching constants under different temperatures and analyzing the thermodynamic parameter. The result revealed that there was a strong fluorescence quenching effect of coptisine analogues on lysozyme. The data indicated both dynamic and static quenchings were involved in the quenching process. The thermodynamic parameters indicated that the interactions of coptisine analogues with lysozyme were driven mainly by hydrophobic force. UV absorption of lysozyme was more negatively affected by a longer alkyl chain. Compared to Cop-C8-6 and Cop-C8-4, Cop-C8-8 had the highest binding constant which is 2.063×10^7.