离子液体胁迫下土壤蔗糖酶活性

Toxicity of Ionic Liquid on Soil Sucrase Activity

采用实验室模拟的方法研究了离子液体1-丁基-3-甲基咪唑四氟硼酸盐对土壤蔗糖酶活性的影响及其动力学和热力学特征。结果表明,短期内不同浓度离子液体胁迫下蔗糖酶呈现激活效应,离子液体浓度越高,对蔗糖酶的激活作用越大。从长期看,低浓度(10mg/kg)离子液体对土壤蔗糖酶前期和后期均表现出激活作用,而其他较高浓度处理均表现为激活-抑制-激活效应;不同浓度离子液体胁迫下蔗糖酶酶促反应的K_m和V_(max)发生一定程度的改变;热力学研究表明,蔗糖酶最适宜温度为320K,对照处理土壤蔗糖酶酶促反应具有最高的反应活化能(E_a)和焓变(△H),不同浓度离子液体胁迫作用降低了土壤酶促反应的活化能,有利于酶-底物络合物的形成。

Toxicity of ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate on soil sucrase activity was studied by laboratory simulation method,and the kinetics and thermal parameters of enzyme catalyzed reaction were also investigated.Results showed that the activation effect of ionic liquids on the soil sucrase activity was found in short term,and the activation effect was better with higher concentration of ionic liquid.But in the long term,activation-inhibitory-activation effect was found in higher concentration rather than the lower concentration（10 mg/kg） with the activation effect in the whole incubation process.Kinetic parameters,K m and V_（max） were changed a certain in different concentrations of ionic liquids due to the changes of the affinity of enzyme to substrate.The optimum temperature of enzymatic reaction was about 320 K,and thermodynamic research showed that highest activation energy（E_a） and activation enthalpy（H） were found in controls,which indicated that the addition of ionic liquid to soil was favorable for the producing of enzyme-substrate complexes.