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Hot Biological Catalysis: Isothermal Titration Calorimetry to Characterize Enzymatic Reactions
Published on: April 4, 2014
[The reaction mechanism of metolachlor and S-isomer with urease]
Hui-jun Liu1, Wei-ping Liu, Ai-ping Chen
1Institute of Environmental Science, Zhejiang University, Hangzhou 310027, China.
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.
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