Dismutation of hydroxylamine to ammonia and nitrite by a novel, membrane-bound enzyme from the cyanobacterium Phormidium uncinatum.
Extracts from ammonium-grown phototrophic cultures of Phormidium uncinatum exhibited a catalytic and stoichiometric formation of nitrite and ammonia from hydrogen peroxide and hydroxylamine. This reaction was due to a novel enzyme (referred to as hydroxylamine dismutase), which was bound to the heavier thylakoid membranes. The enzyme was solubilized from the membranes by detergent treatment and further purified by ion-exchange chromatography. On the basis of inhibitor studies, the involvement of metal ions and sulfhydryl groups in the characteristic reaction is suggested.
Bagchi
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Department of Microbiology, University of Bayreuth, F.R.G.
Kleiner
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D000641:Ammonia; D002462:Cell Membrane / Q000201:enzymology; D002852:Chromatography, Ion Exchange; D000458:Cyanobacteria / Q000201:enzymology*; D019811:Hydroxylamine; D006898:Hydroxylamines / Q000378:metabolism*; D007700:Kinetics; D010088:Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism*; D012995:Solubility; D014867:Water
D006898:Hydroxylamines; D014867:Water; D019811:Hydroxylamine; D000641:Ammonia; D010088:Oxidoreductases; C066342:hydroxylamine dismutase