Purification and characterization of chlorobenzene cis-dihydrodiol dehydrogenase from Xanthobacter flavus 14p1.
Chlorobenzene cis-dihydrodiol dehydrogenase was purified to homogeneity from Xanthobacter flavus 14p1, which used 1,4-dichlorobenzene as the sole source of carbon and energy. The enzyme converted a number of halogenated substrates with high specific activity. The pI of the native chlorobenzene cis-dihydrodiol dehydrogenase was 5.4, and the molecular mass was approximately 100 kDa, as determined by gel filtration. The enzyme was composed of four apparently identical subunits with a molecular mass of 26.5 kDa. The Michaelis constant for 3,6-dichlorobenzene cis-dihydrodiol (210 microM) was lower than for benzene cis-dihydrodiol (780 microM), while the specific activity with benzene cis-dihydrodiol (63 units/ mg) was higher than with 3,6-dichlorobenzene cis-dihydrodiol (32 units/mg). Chlorobenzene cis-dihydrodiol dehydrogenase accepted also NADP+ as cosubstrate; however, the activity was reduced to 14% of that with NAD+. The enzymic activity was inhibited by mercuric chloride and to a lesser extent by the metal-ion chelators 8-hydroxyquinoline and KCN.
Spiess
E
E
FG Technische Biochemie, Institut für Biotechnologie, TU Berlin, Seestrasse 13, D-13353 Berlin, Germany.
Görisch
H
H
D001555:Benzene Derivatives / Q000378:metabolism*; D001673:Biodegradation, Environmental; D002722:Chlorobenzenes / Q000378:metabolism*; D006088:Gram-Negative Aerobic Bacteria / Q000201:enzymology*; D007526:Isoelectric Point; D007700:Kinetics; D008970:Molecular Weight; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D010088:Oxidoreductases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D013379:Substrate Specificity; D013696:Temperature
D001555:Benzene Derivatives; D002722:Chlorobenzenes; D009243:NAD; D009249:NADP; D010088:Oxidoreductases; C071576:chlorobenzene dehydrogenase