title: Enzymology of the degradation of (di)chlorobenzenes by Xanthobacter flavus 14p1.
abstract: Xanthobacter flavus 14p1 used 1,4-dichlorobenzene as the sole source of carbon and energy but did not grow on other (chloro)aromatic compounds. 1,4-Dichlorobenzene was attacked by a chlorobenzene dioxygenase, and the intermediate chlorocatechol was metabolized by the modified ortho pathway. All enzymes necessary to convert 1, 4-dichlorobenzene to 3-oxoadipate showed a low substrate specificity and also accepted the respective intermediates of chlorobenzene or 1, 3-dichlorobenzene degradation. Of the three compounds chlorobenzene, 1,4-dichlorobenzene, and 1,3-dichlorobenzene, the latter was the most toxic for X. flavus 14p1. Furthermore, 1,3-dichlorobenzene did not induce chlorocatechol 1,2-dioxygenase activity of the organism. Chlorobenzene, however, induced chlorocatechol 1,2-dioxygenase, dienelactone hydrolase, and maleylacetate reductase activities. As demonstrated by chloride release, also chlorobenzene dioxygenase, chlorobenzene cis-dihydrodiol dehydrogenase, and chloromuconate cycloisomerase activities were present in chlorobenzene-induced cells, but chlorobenzene failed to support growth. Presumably a toxic compound was formed from one of the intermediates.
authors.affiliation: Fachgebiet Technische Biochemie, Institut für Biotechnologie, Technische Universität Berlin, Seestrasse 13, D-13353 Berlin, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Sommer
authors.forename: H
authors.initials: H
authors.lastname: Görisch
mesh_terms: D001673:Biodegradation, Environmental; D002265:Carboxylic Ester Hydrolases / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D002722:Chlorobenzenes / Q000737:chemistry / Q000378:metabolism*; D049308:Dioxygenases; D004785:Environmental Pollutants / Q000378:metabolism; D006088:Gram-Negative Aerobic Bacteria / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D019753:Intramolecular Lyases; D007535:Isomerases / Q000378:metabolism; D010088:Oxidoreductases / Q000378:metabolism; D044925:Oxidoreductases Acting on CH-CH Group Donors; D010105:Oxygenases / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D002712:Chlorides; D002722:Chlorobenzenes; D004785:Environmental Pollutants; C042146:1,3-dichlorobenzene; C018511:4-dichlorobenzene; D010088:Oxidoreductases; D010105:Oxygenases; D049308:Dioxygenases; C071575:chlorobenzene dioxygenase; D044925:Oxidoreductases Acting on CH-CH Group Donors; C071576:chlorobenzene dehydrogenase; C021530:maleylacetate reductase; D002265:Carboxylic Ester Hydrolases; C046130:carboxymethylenebutenolidase; D007535:Isomerases; D019753:Intramolecular Lyases; C055773:chloromuconate cycloisomerase