Janssen D B, van der Ploeg J R, Pries F
Department of Biochemistry, University of Groningen, The Netherlands.
Environ Health Perspect. 1995 Jun;103 Suppl 5(Suppl 5):29-32. doi: 10.1289/ehp.95103s429.
The bacterial degradation and detoxification of chlorinated xenobiotic compounds requires the production of enzymes that are capable of recognizing and converting compounds which do not occur at significant concentrations in nature. We have studied the catabolic route of 1,2-dichloroethane as an example of a pathway for the conversion of such a synthetic compound. In strains of Xanthobacter and Ancylobacter that have been isolated on 1,2-dichloroethane, the first catabolic step is catalyzed by a hydrolytic haloalkane dehalogenase. The enzyme converts 1,2-dichloroethane to 2-chloroethanol but is also active with many other environmentally important haloalkanes such as methylchloride, methylbromide, 1,2-dibromoethane, epichlorohydrin, and 1,3-dichloropropene. Further degradation of 2-chloroethanol proceeds by oxidation to the carboxylic acid and dehalogenation to glycolate. The aldehyde dehydrogenase prevents toxicity of the reactive chloroacetaldehyde that is formed as an intermediate and is necessary for establishing a functional 2-chloroethanol degradative pathway in a strain that is not capable of growth on this compound.
细菌对氯化异源生物化合物的降解和解毒需要产生能够识别和转化自然界中不存在显著浓度的化合物的酶。我们以1,2 - 二氯乙烷的分解代谢途径为例，研究了这种合成化合物的转化途径。在从1,2 - 二氯乙烷中分离出的黄杆菌属和柄杆菌属菌株中，第一步分解代谢由水解卤代烷脱卤酶催化。该酶将1,2 - 二氯乙烷转化为2 - 氯乙醇，但对许多其他对环境重要的卤代烷也有活性，如氯甲烷、溴甲烷、1,2 - 二溴乙烷、环氧氯丙烷和1,3 - 二氯丙烯。2 - 氯乙醇的进一步降解通过氧化为羧酸和脱卤为乙醇酸进行。醛脱氢酶可防止作为中间体形成的活性氯乙醛产生毒性，而活性氯乙醛对于在不能利用该化合物生长的菌株中建立功能性的2 - 氯乙醇降解途径是必需的。
