%A LIU Hui-jun;LIU Wei-ping;CHEN Ai-ping;YANG Wei-chun %T The Reaction Mechanism of Metolachlor and S-Isomer with Urease %0 Journal Article %D 2004 %J SPECTROSCOPY AND SPECTRAL ANALYSIS %R %P 166-168 %V 24 %N 02 %U {https://www.gpxygpfx.com/CN/abstract/article_4361.shtml} %8 2004-02-26 %X The binding of metolachlor and S-Isomer to urease in aqueous solution was studied using UV difference spectrum and fluorescence spectrum. According to the results of the UV difference spectrum curve, the UV difference adsorption ΔA changed rapidly when herbicide concentration increased from 0.0 to 1.6 μmol·L-1. UV difference spectra were red-shifted and absorb-peaks became lower. It was shown that herbicide can quench the urease fluorescence mainly through a static quenching procedure. The binding constant K and the number of binding site n were calculated according to the fluorescence quenching results. For metolachlor, K=1.49×103 L·mol-1 and n was 0.84; for S-isomer, K=2.22×103 L·mol-1 and n was 0.89.