2,4,6-trinitrotoluene reduction by carbon monoxide dehydrogenase from Clostridium thermoaceticum

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 can converted to (24DHANT), which slowly converted to the Bamberger rearrangement product. Apparent ii(rn) and k(cat) values of TNT reduction were 165 +/- 43 mu m for TNT and 400 +/- 94 s(-1), respectively, Cyanide, an inhibitor far the CO/CO2 oxidation/reduction activity of CODH, inhibited the TNT degradation activity of CODH.