Nitrite Formation from Hydroxylamine and Oximes by Pseudomonas aeruginosa

Abstract

Nitrite was formed from hydroxylamine and several oximes by intact cells and extracts of Pseudomonas aeruginosa . The activity was induced by the presence of oximes in the culture medium. Nitroalkanes were not intermediates in the conversion of acetaldoxime, acetone oxime, or butanone oxime to nitrite, since nitromethane inhibited the formation of nitrite from the nitro compounds but not from the corresponding oximes. The oxime apparently functions as a constant source of hydroxylamine during growth of the bacterium. Hydroxylamine at low concentration was converted stoichiometrically to nitrite by extracts of the bacterium; high concentrations were inhibitory. Nicotinamide adenine dinucleotide phosphate, oxygen, and other unidentified cofactors were necessary for the reaction. Actively nitrifying extracts possessed no hydroxylamine-cytochrome c reductase activity. Hyponitrite, nitrous oxide, and nitric oxide were not metabolized.