化学
环境化学
脱氢酶
镉
土壤水分
土壤污染
有机质
毒性
土壤有机质
乳酸脱氢酶
动力学
酶
生物化学
生态学
生物
有机化学
物理
量子力学
作者
Xiangping Tan,Ziquan Wang,Guannan Lu,Wenjun He,Gehong Wei,Feng Huang,Xinlan Xu,Weijun Shen
标识
DOI:10.1016/j.jhazmat.2017.01.055
摘要
Soil dehydrogenase plays a role in the biological oxidation of soil organic matter and can be considered a good measure of the change of microbial oxidative activity under environmental pollutions. However, the kinetic characteristic of soil dehydrogenase under heavy metal stresses has not been investigated thoroughly. In this study, we characterized the kinetic characteristic of soil dehydrogenase in 14 soil types, and investigated how kinetic parameters changed under spiked with different concentrations of cadmium (Cd). The results showed that the Km and Vmax values of soil dehydrogenase was among 1.4-7.3mM and 15.9-235.2μMh-1 in uncontaminated soils, respectively. In latosolic red soil and brown soil, the inhibitory kinetic mechanism of Cd to soil dehydrogenase was anticompetitive inhibition with inhibition constants (Ki) of 12 and 4.7mM, respectively; in other soils belonged to linear mixed inhibition, the values of Ki were between 0.7-4.2mM. Soil total organic carbon and Ki were the major factors affecting the toxicity of Cd to dehydrogenase activity. In addition, the velocity constant (k) was more sensitive to Cd contamination compared to Vmax and Km, which was established as an early indicator of gross changes in soil microbial oxidative activity caused by Cd contamination.
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