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 re duced products of TNT transformation were separated and appear to be identi cal 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 rearrange ment product of 2,4-dihydroxylamino-6-nitrotoluene. In the presence of satu rating CO, CODH catalyzed the conversion of TNT to two monohydroxylamino de rivatives (2HA46DNT) and (4HA26DNT) with (4HA26DNT) as the dominant isomer, These derivatives were then can converted to (24DHANT), which slowly conve rted to the Bamberger rearrangement product. Apparent ii(rn) and k(cat) val ues of TNT reduction were 165 +/- 43 mu m for TNT and 400 +/- 94 s(-1), res pectively, Cyanide, an inhibitor far the CO/CO2 oxidation/reduction activit y of CODH, inhibited the TNT degradation activity of CODH.