Investigation On Spectra Of Interaction Between Several Herbicides And Serum Albumin

Herbicides are used world-wide in agriculture. Because herbicides can be degraded hardly, herbicides exist in water, air and soil through surface runoff, evaporation and infiltration. Also, herbicides can cause varying degrees of damage to the human body through the food chain. Protein composed of organic macromolecular is the basis of material life and the main carrier of life activities, it can function as the storage depot for endogenous and exogenous toxins, and it has important physiological functions. Serum albumin is the most abundant protein in plasma and easily becomes the target for exogenous substances, so to study the interaction between herbicides and serum albumin is particularly important for its metabolic process in organisms and biological effects. In this paper, the interaction of phenylurea herbicides (diuron and chlolortoluron) with bovine serum albumin (BSA), and the interaction of triazine herbicides (simetryne, ametryn and terbutryn) with human serum albumin (HSA) were investigated using UV-vis absorption spectroscopy, fluorescence spectroscopy and CD spectroscopy. The results are as follows.(1) Diuron and chlolortoluron could all obviously interact with BSA molecule and the interaction strength was related to some factors such as the concentration of diuron and chlolortoluron, and reaction temperature. Hyperchromic effect was observed in the UV-vis spectrum and the fluorescence of BSA molecules was gradually quenched in the observed fluorescence spectra. The quenching modes were static quenching with dynamic quenching. The number of binding sites (n) was equal to 1 and the binding distance was less than 7 nm. The interaction was carried out spontaneously by non-radioactive energy transfer. Synchronous fluorescence spectra indicated that diuron and chlolortoluron could combine with tryptophan residues and tyrosine residues. But they combined with tryptophan residues better than with tyrosine residues. The binding sites were different under different temperatures. The CD spectra showed that diuron and chlolortoluron could destruct the secondary structure of BSA molecules.(2) Simetryne, ametryn and terbutryn could all obviously interact with HSA molecule and the interaction strength was related to such factors as the concentration of simetryne, ametryn and terbutryn and reaction temperature. Hyperchromic effect was observed in the UV-vis spectrum and the fluorescence of HSA molecules was gradually quenched in the observed fluorescence spectra and the high temperature was propitious to the quenching of the HSA fluorescence. The quenching mode was static quenching and the number of binding sites (n) was equal to 1. The binding distance was less than 7 nm, and the interaction was carried out spontaneously by non-radioactive energy transfer. Synchronous fluorescence spectra showed that simetryne, ametryn and terbutryn could combine with tryptophan residues and tyrosine residues. They combined with tryptophan residues better than tyrosine residues. The CD spectra showed that simetryne, ametryn and terbutryn could destruct the secondary structure of HSA molecule. Simetryne, ametryn and terbutryn interacted with HSA in Site I of protein subdomain ⅡA.