The enzymology of trinitrotoluene reduction

Bacillus subtilis, whose growth is inhibited by 2,4,6-trinitrotoluene (TNT), possesses the ability to metabolically reduce TNT to a variety of amino- and hydroxylaminotoluene derivatives. Cell-free extracts of this culture are capable of reducing TNT, utilizing either nicotinamide-adenine dinucleotide (NAD) or nicrotinamide-adenine dinucleotide phosphate (NADP) as cofactors. The NAD-linked system has a narrower pH range and is more sensitive to heat than the NADP-mediated system. Both react with essentially the same nitro aromatic substrates, elute from Sephadex columns at the same time, and show the same solubilities in ammonium sulphate solutions. The cell-free extract from Pseudomonas aeruginosa, whose growth is not inhibited by TNT, also has NAD- and NADP-linked TNT reductases with almost identical characteristics as those from B. subtilis.