Anaerobic ammonium oxidation is a recent addition to the microbial nitrogen cycle, and its metabolic pathway, including the production and conversion of its intermediate hydrazine, is not well understood. Therefore, the effect of hydroxylamine addition on the hydrazine metabolism of anaerobic ammonium-oxidizing (anammox) bacteria was studied both experimentally and by mathematical modeling. It ...

The chemoautotrophic bacterium, Nitrosomonas europaea, derives its energy from the oxidation of ammonia to nitrite. Several investigators have noted that the ability to oxidize ammonia is entirely lost upon rupture of the Nitrosomonas cell, and that, although cell-free preparations retain a small fraction of the hydroxylamine-oxidizing activity, only 30 to 70% of the total hydroxylamine that is...

N-(2-methoxyphenyl)hydroxylamine is a human metabolite of the industrial and environmental pollutants and bladder carcinogens 2-methoxyaniline (o-anisidine) and 2-methoxynitrobenzene (o-nitroanisole). Here, we investigated the ability of hepatic microsomes from rat and rabbit to metabolize this reactive compound. We found that N-(2-methoxyphenyl)hydroxylamine is metabolized by microsomes of bot...

In spite of its physiological importance acetylcholine has been determinable chemically only after isolation by time-consuming procedures. Of necessity workers in this field have resorted to pharmacological bioassays whose specificity seems open to doubt. The finding that choline is readily acetylated by the action of a coenzyme-linked enzyme system in which adenosine triphosphate serves as an ...

The synthesis of y-glutamylhydroxamic acid from glutamine and hydroxylamine is catalyzed by glutamine synthetase in the presence of adenosine diphosphate, inorganic phosphate, and magnesium ions (l), and also by other enzyme preparations (2,3) that do not exhibit a requirement for nucleotides or metal ions. The synthesis of y-glutamylhydroxamic acid from glutamic acid and hydroxylamine that is ...

Piperidine nitroxides such as TEMPOL have been widely used as antioxidants in vitro and in vivo. MitoTEMPOL is a mitochondria-targeted derivative of TEMPOL designed to protect mitochondria from the oxidative damage that they accumulate, but once there is rapidly reduced to its hydroxylamine, MitoTEMPOL-H. As little is known about the antioxidant efficacy of hydroxylamines, this study has assess...