Study On The Toxic Effect And Mechanism Of N-Butanol And Isobutanol On Lysozyme

n-Butanol,as one of the VOCs,is used in a wide range leading to air pollution and health hazards.Therefore,it is imperative to study the environmental toxicology of the two.In this paper,lysozyme was selected as a representative biomacromolecule.Based on the theory of environmental molecular toxicology,the toxicity of n-Butanol and isopropanol to lysozyme was investigated by multi-spectral and molecular docking approach.The mechanism of the toxicity of n-butanol and isopropanol to lysozyme is different.The specific results are as follows.The fluorescence spectra results showed that n-Butanol could form a complex with lysozyme and make fluorophores far away from fluorescence quenchers.The results of synchronous fluorescence and three-dimensional spectra indicates that the microenvironment around the tryptophan residues was altered by n-Butanol.The UV-vis and CD spectra suggested that the second structure of lysozyme was changed by n-Butanol with the increase of a-helix content and the decrease of ?-sheet content.The molecular docking study illustrated the results of binding site and binding force between n-Butanol and lysozyme,which was consistent with spectroscopic experiments.However,lysozyme activity was affected little by n-Butanol,which was due to that n-Butanol did not bind to the active site of lysozyme.Fluorescence spectra showed that isopropanol resulted in the quenching effect of the fluorescence of lysozyme.The results of synchronous fluorescence suggested that the microenvironment of tryptophan residues and tyrosine residues became more hydrophobic.UV and circular dichroism spectra of the same results showed that isopropanol make secondary structure of lysozyme more loose.Binding sites are not the same witn n-Butanol but the binding forces were all hydrogen bonds and hydrophobic forces.Enzyme activity test results also suggest that isopropanol did not bind to the center of lysozyme activity,so little effect on enzyme activity.This study not only reveals the toxic effects and mechanism of n-butanol and isopropanol on lysozyme,but also provides the corresponding information for the research of lysozyme in medical,food preservative and bioengineering and provide the appropriate information to support the role of n-butanol and isopropanol.