荧光法研究不同离子对溶菌酶的猝灭作用

本文利用荧光法,在生理pH(7.37±0.02)条件下,分别测定了Fe3+、Cu2+、Ni2+、Co2+、NO2-、I-、盐酸胍对溶菌酶的猝灭作用。用荧光猝灭法求得不同猝灭剂对溶菌酶的猝灭常数KSV、生成常数KA、离解常数KD、结合位点数n和热力学参数ΔrGmΘ、ΔrHmΘ、ΔrSmΘ。据此判断了体系中猝灭剂对溶菌酶的作用机理。I-对溶菌酶的猝灭是动态猝灭,而Fe3+、Cu2+、NO2-Ni2+、Co2+及盐酸胍对溶菌酶是静态猝灭;Fe3+、Cu2+、Ni2+、Co2+与溶菌酶之间的作用力主要为氢键、范德华力;NO2-与溶菌酶间的作用力主要为静电作用力;I-与溶菌酶之间的作用力主要为疏水作用力。在分子水平上理解这些外源性化合物与溶菌酶的作用机理具有及其重要意义。

Study of different ions on fluerescence quenching of lysozyme

Fluorescence quenching of lysozyme with various ions,such as Fe3+,Cu2+,Ni2+,Co2+,NO-2,I-and Guanidine·HCl were determined at physiological pH(7.37±0.02).Quenching constant KSV,formation constant(KA),dissociation constant(KD),the number of binding sites(n)and thermodynamics functions of ΔrGmΘ、ΔHGmΘas well as ΔrSmΘ were obtained for various quenchers to lysozyme by fluorescence method.The quenching mechanism of lysozyme with various quenchers was determined through thermodynamics functions.I-was a dynamic quenching process,and Fe3+,Cu2+,Ni2+,Co2+,NO-2 and guanidine hydrochloride were the static quenching processes for lysozyme.The interaction force of Fe3+,Cu2+,Ni2+,Co2+with lysozyme were hydrogen bond and Van der Waals force;NO-2 was mainly electrostatic force and I-was hydrophobic interaction.It is a vital important for us to understand the interaction mechanism between exogenous compounds and lysozyme.