温度对Cd抑制土壤脲酶影响机理研究

Effects of Temperature on Mechanism of Soil Urease Activity Inhibited by Cd

通过土壤培养实验、紫外光谱和荧光光谱技术,研究了不同温度下Cd对土壤脲酶催化活性、动力学性质的影响及其机理。结果表明:(1)在供试温度范围内,土壤脲酶活性、动力学参数V_(max)和V_(max)/K_m值与温度呈正相关,且土壤脲酶活性随着培养时间延长呈现先增后减的趋势;(2)土壤脲酶活性、动力学参数V_(max)和V_(max)/K_m值与Cd^(2+)呈显著负相关,表明Cd对土壤脲酶的抑制作用为非竞争性抑制,且抑制程度随处理温度升高而加强;(3)低浓度Cd处理刀豆脲酶后,随着体系中Cd^(2+)的增加,脲酶的紫外吸收光谱发生红移,荧光发射峰发生蓝移。

By fluorescence and different UV-absorption spectra ,the effects of Cd on the activity and kinetics property of soil urease at different temperatures were studied in soil culture under laboratory conditions.Results showed that .（1） Under tested temperature scope, soil urease activity, Vmax and Vmax/Km value were positice with temperature, soil urease activity show enhanced-inhibited tendency with culture time prolonged. （2） A signinficant relationship between soil urease activity, Vmax,Vmax/Km and Cd indicating non-competitive inhibition interactions between Cd and soil urease. And the inhibition degree would enhance with temperature increased. （3） With low Cd^2＋ trreatment, urease UV different spectra were red-shifted and fluorescence spectra were blue-shifted.