Oldenhuis R, Oedzes J Y, van der Waarde J J, Janssen D B
Department of Biochemistry, University of Groningen, The Netherlands.
Appl Environ Microbiol. 1991 Jan;57(1):7-14. doi: 10.1128/aem.57.1.7-14.1991.
The kinetics of the degradation of trichloroethylene (TCE) and seven other chlorinated aliphatic hydrocarbons by Methylosinus trichosporium OB3b were studied. All experiments were performed with cells grown under copper stress and thus expressing soluble methane monooxygenase. Compounds that were readily degraded included chloroform, trans-1,2-dichloroethylene, and TCE, with Vmax values of 550, 330, and 290 nmol min-1 mg of cells-1, respectively. 1,1-Dichloroethylene was a very poor substrate. TCE was found to be toxic for the cells, and this phenomenon was studied in detail. Addition of activated carbon decreased the acute toxicity of high levels of TCE by adsorption, and slow desorption enabled the cells to partially degrade TCE. TCE was also toxic by inactivating the cells during its conversion. The degree of inactivation was proportional to the amount of TCE degraded; maximum degradation occurred at a concentration of 2 mumol of TCE mg of cells-1. During conversion of [14C]TCE, various proteins became radiolabeled, including the alpha-subunit of the hydroxylase component of soluble methane monooxygenase. This indicated that TCE-mediated inactivation of cells was caused by nonspecific covalent binding of degradation products to cellular proteins.
研究了甲基孢囊菌OB3b对三氯乙烯（TCE）和其他七种氯代脂肪烃的降解动力学。所有实验均使用在铜胁迫下生长并因此表达可溶性甲烷单加氧酶的细胞进行。易于降解的化合物包括氯仿、反式-1,2-二氯乙烯和TCE，其Vmax值分别为550、330和290 nmol min-1 mg细胞-1。1,1-二氯乙烯是一种很差的底物。发现TCE对细胞有毒，并对这一现象进行了详细研究。添加活性炭通过吸附降低了高浓度TCE的急性毒性，缓慢的解吸使细胞能够部分降解TCE。TCE在转化过程中使细胞失活也具有毒性。失活程度与TCE降解量成正比；在TCE浓度为2 μmol mg细胞-1时发生最大降解。在[14C]TCE转化过程中，各种蛋白质被放射性标记，包括可溶性甲烷单加氧酶羟化酶组分的α亚基。这表明TCE介导的细胞失活是由降解产物与细胞蛋白质的非特异性共价结合引起的。
