title: [The reaction mechanism of metolachlor and S-isomer with urease].
abstract: 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 deltaA changed rapidly when herbicide concentration increased from 0.0 to 1.6 micromol x L(-1) x 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 x 10(3) L x mol(-1) and n was 0.84; for S-isomer, K=2.22 x 10(3) L x mol(-1) and n was 0.89.
authors.affiliation: Institute of Environmental Science, Zhejiang University, Hangzhou 310027, China.
authors.forename: Hui-jun
authors.initials: HJ
authors.lastname: Liu
authors.forename: Wei-ping
authors.initials: WP
authors.lastname: Liu
authors.forename: Ai-ping
authors.initials: AP
authors.lastname: Chen
authors.forename: Wei-chun
authors.initials: WC
authors.lastname: Yang
mesh_terms: D000081:Acetamides / Q000633:toxicity*; D001665:Binding Sites / Q000187:drug effects; D002942:Circular Dichroism; D007536:Isomerism; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D055672:Static Electricity; D013696:Temperature; D014466:Ultraviolet Rays; D014510:Urease / Q000187:drug effects* / Q000378:metabolism
chemical_list: D000081:Acetamides; D014510:Urease; C051786:metolachlor