title: 2,4,6-trinitrotoluene reduction by carbon monoxide dehydrogenase from Clostridium thermoaceticum.
abstract: Purified CO dehydrogenase (CODH) from Clostridium thermoaceticum catalyzed the transformation of 2,4,6-trinitrotoluene (TNT). The intermediates and reduced products of TNT transformation were separated and appear to be identical to the compounds formed by C. acetobutylicum, namely, 2-hydroxylamino-4,6-dinitrotoluene (2HA46DNT), 4-hydroxylamino-2,6-dinitrotoluene (4HA26DNT), 2, 4-dihydroxylamino-6-nitrotoluene (24DHANT), and the Bamberger rearrangement product of 2,4-dihydroxylamino-6-nitrotoluene. In the presence of saturating CO, CODH catalyzed the conversion of TNT to two monohydroxylamino derivatives (2HA46DNT and 4HA26DNT), with 4HA26DNT as the dominant isomer. These derivatives were then converted to 24DHANT, which slowly converted to the Bamberger rearrangement product. Apparent K(m) and k(cat) values of TNT reduction were 165 +/- 43 microM for TNT and 400 +/- 94 s(-1), respectively. Cyanide, an inhibitor for the CO/CO(2) oxidation/reduction activity of CODH, inhibited the TNT degradation activity of CODH.
authors.affiliation: Department of Biochemistry and Cell Biology and the Institute of Biosciences and Bioengineering, Rice University, Houston, Texas 77005-1892, USA.
authors.forename: S
authors.initials: S
authors.lastname: Huang
authors.forename: P A
authors.initials: PA
authors.lastname: Lindahl
authors.forename: C
authors.initials: C
authors.lastname: Wang
authors.forename: G N
authors.initials: GN
authors.lastname: Bennett
authors.forename: F B
authors.initials: FB
authors.lastname: Rudolph
authors.forename: J B
authors.initials: JB
authors.lastname: Hughes
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D003013:Clostridium / Q000201:enzymology*; D003486:Cyanides / Q000494:pharmacology; D007700:Kinetics; D009097:Multienzyme Complexes / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism*; D010084:Oxidation-Reduction; D014303:Trinitrotoluene / Q000378:metabolism*
chemical_list: D003486:Cyanides; D009097:Multienzyme Complexes; D014303:Trinitrotoluene; D000445:Aldehyde Oxidoreductases; C019823:carbon monoxide dehydrogenase