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a partial resolution and reconstitution of the ammonia-oxidizing system of nitrosomonas europaea: role of cytochrome c554.the cell-free ammonia-oxidizing system of nitrosomonas europaea was resolved into three major fractions: a membrane fraction containing cytochrome a1 and c-type cytochromes, a fraction with hydroxylamine-cytochrome c reductase and a cytochrome c fraction. the ammonia-oxidizing activity was reconstituted by the combination of these three fractions. the activity was more consistently reconstituted by adding nitrosomonas cytochrome c554 to the membrane fraction. the hydroxylamine-cytochrome c reduc ...19816271364
some properties of glutamine synthetase from the nitrifying bacterium nitrosomonas europaea.nitrosomonas europaea oxidizes ammonia to nitrite, thereby deriving energy for growth. glutamate dehydrogenase (nadp+) (ec 1.4.1.4) is the main route for the incorporation of ammonia into glutamic acid, because glutamate synthase (nadph)(ec 1.4.1.13) was not detected in cell-free extracts of n. europaea. some properties of a partially purified glutamine synthetase (ec 6.3.1.2) have been determined, namely the effects of ph and metal ions, substrate requirements, km and ki values, based on biosyn ...19816122437
hydroxylamine oxidoreductase: a 20-heme, 200 000 molecular weight cytochrome c with unusual denaturation properties which forms a 63 000 molecular weight monomer after heme removal. 19816274384
oxidation of ammonia by nitrosomonas europaea. definite 18o-tracer evidence that hydroxylamine formation involves a monooxygenase.nh2oh, the first intermediate in the oxidation of nh4+ to nitrite by the nitrifying bacterium, nitrosomonas europaea, was recovered as the oxime of cyclohexanone. 15n, 18o-tracer experiments using highly enriched 15nh4cl and 18o2 yielded oxime that was correspondingly highly enriched (greater than or equal to 92 atom %) in these isotopes. these results show that the source of nh2oh is largely or entirely nh4+, as opposed to hydrazine, which was added to inhibit the further oxidation of nh2oh to ...19817287737
resolution of multiple heme centers of hydroxylamine oxidoreductase from nitrosomonas. 2. mössbauer spectroscopy.hydroxylamine oxidoreductase (hao) isolated from nitrosomas europaea is a complex protein of mr 220000 with an (alpha beta)3 subunit structure. each alpha beta subunit contains seven c-type hemes and approximately one unusual prosthetic group termed p-460. we have studied this enzyme in the oxidized and reduced states by using mössbauer spectroscopy. in the fully reduced enzyme, approximately seven hemes per alpha beta subunit contributed to one spectrum characteristic of low-spin ferrous heme. ...19827126527
respiration-dependent proton translocation in nitrosomonas europaea and its apparent absence in nitrobacter agilis during inorganic oxidations.oxygen pulse experiments were carried out with the nitrifying bacteria nitrosomonas europaea and nitrobacter agilis and with spheroplasts and everted vesicles prepared from nitrobacter agilis. in addition to thiocyanate, the salting-in anions perchlorate and trichloroacetate proved to be permeant and effective in allowing respiration-dependent proton translocation with nitrosomonas europaea. valinomycin-k+, however, was generally ineffective in this respect with nitrosomonas europaea. the observ ...19826277846
cytochrome c554 as a possible electron donor in the hydroxylation of ammonia and carbon monoxide in nitrosomonas europaea.mechanism of ammonia oxidation was studied in the reconstituted system of nitrosomonas membrane fraction plus the nitrosomonas cytochrome c554. the cytochrome c554 was reduced by hydroxylamine, hydrazine, and ammonia and the reduced cytochrome was oxidized upon the addition of ammonia or carbon monoxide. the oxidation of carbon monoxide in the presence of hydroxylamine or hydrazine was studied as a possible assay method for ammonia hydroxylase where hydroxylamine or hydrazine was supplying the r ...19826293683
characterization of the c-type cytochromes of nitrosomonas europaea with the aid of fluorescent gels.when a total soluble extract of nitrosomonas europaea was denatured with dodecyl sulphate, subjected to dodecyl sulphate/polyacrylamide-gel electrophoresis and illuminated with near-u.v. light, eight bands of protein fluorescence were observed. all but one of these bands were red in colour, a property characteristic of c-type cytochromes. standard techniques were used to purify soluble c-type cytochromes from this organism, and it was then possible to assign all but two very minor bands to speci ...19826299271
effects of polychlorinated biphenyls and environmental biotransformation products on aquatic nitrification.the effects of polychlorinated biphenyls (pcbs) on nitrification were examined for pure cultures and natural reservoir samples. pcbs at concentrations greater than 10 microgram liter-1 inhibited nitrification, principally ammonium oxidation, in one of two natural reservoir environments. however, this inhibition could not be reproduced in pure high-cell-density cultures or in previously contaminated reservoir waters. a pcb environmental biotransformation product, p-chlorophenylglyoxylic acid, and ...19826805434
incorporation of organic compounds into cell protein by lithotrophic, ammonia-oxidizing bacteria.incorporation of organic compounds into cell protein by the obligate chemolithotrophs nitrosomonas spec., nitrosococcus oceanus, nitrosococcus mobilis, nitrosovibrio tenuis, nitrosolobus spec., and nitrosospira spec. was studied. in the presence of ammonia as energy source organic substrates were supplied. distribution of 14c into cell amino acids arising from 14c-labelled glucose, na-pyruvate, and na-acetate was investigated. while carbon from glucose was distributed unrestricted, carbon from p ...19827149699
reaction of oxygen with hydroxylamine oxidoreductase of nitrosomonas: fast kinetics. 19827117545
resolution of multiple heme centers of hydroxylamine oxidoreductase from nitrosomonas. 1. electron paramagnetic resonance spectroscopy. 19826289867
stimulation of autotrophic ammonium oxidation in rice rhizosphere soil by the insecticide carbofuran.the application of the insecticide carbofuran (technical or formulated) to rice rhizosphere soil suspensions at 10 and 100 ppm (mug/ml) of active ingredient distinctly stimulated the autotrophic oxidation of ammonium. evidence suggested that nitrosomonas sp. was enriched in the presence of carbofuran. formulated carbofuran (furadan 3g) exhibited a more pronounced stimulation of ammonium oxidation than that exhibited by technical-grade (99.5%) carbofuran, a result which was attributed to the caco ...198216346046
o isotope shift in n nmr analysis of biological n-oxidations: h(2)o-no(2) exchange in the ammonia-oxidizing bacterium nitrosomonas.the (18)o/(16)o shifts in (15)n nmr were determined for nitrite (0.13 ppm or 4.2 hz at 7.05 t) and nitrate (0.056 ppm or 1.7 hz at 7.05 t) at neutral ph. the technique, which allows clear differentiation between (16)o and (18)o derivatives of (15)n, was used to assess the source of oxygens in nitrite produced by oxidation of ammonia in nitrosomonas. the two oxygens of nitrite produced by cell-catalyzed oxidation of ammonia or hydroxylamine had the (16)o/(18)o isotope composition of water. nitros ...198216593233
immobilization of nitrosomonas europaea cells with polyelectrolyte complex.cell immobilization with polyelectrolyte complex prepared from strongly polyacidic and polybasic ions was investigated for cells from nitrosomonas europaea (atcc 25978). trimethylammonium glycol chitosan (tgci) and potassium poly(vinyl-alcohol) sulfate (kpvs) were used. the immobilization was carried out by directly mixing both polymer solutions with the culture broth: an excess of tgci was first added to the culture broth to aggregate the cells, and then kpvs was added to form the complex with ...198218546459
methane oxidation by nitrosococcus oceanus and nitrosomonas europaea.chemolithotrophic ammonium-oxidizing and nitrite-oxidizing bacteria including nitrosomonas europaea, nitrosococcus oceanus, nitrobacter sp., nitiospina gracilis, and nitrococcus mobilis were examined as to their ability to oxidize methane in the absence of ammonium or nitrite. all ammonium oxidizers tested had the ability to oxidize significant amounts of methane to co(2) and incorporate various amounts into cellular components. none of the nitrite-oxidizing bacteria were capable of methane oxid ...198316346190
population ecology of nitrifiers in a stream receiving geothermal inputs of ammonium.the distribution, activity, and generic diversity of nitrifying bacteria in a stream receiving geothermal inputs of ammonium were studied. the high estimated rates of benthic nitrate flux (33 to 75 mg of n . m . h) were a result of the activity of nitrifiers located in the sediment. nitrifying potentials and ammonium oxidizer most probable numbers in the sediments were at least one order of magnitude higher than those in the waters. nitrifiers in the oxygenated surface (0 to 2 cm) sediments were ...198316346261
inhibition of chemoautotrophic nitrification by sodium chlorate and sodium chlorite: a reexamination.the oxidation of nh(4) by nitrosomonas europaea was insensitive to 10 mm naclo(3) (sodium chlorate) but was strongly inhibited by naclo(2) (sodium chlorite; k(i), 2 mum). the oxidation of no(2) by nitrobacter winogradskyi was inhibited by both clo(3) and clo(2) (k(i) for clo(2), 100 mum). n. winogradskyi reduced clo(3) to clo(2) under both aerobic and anaerobic conditions, and as much as 0.25 mm clo(2) was detected in the culture filtrate. in mixed n. europaea-n. winogradskyi cell suspensions, t ...198316346262
resolution of the hemes of hydroxylamine oxidoreductase by redox potentiometry and optical spectroscopy.optical spectroscopy combined with redox potentiometry has resolved the hemes of hydroxylamine oxidoreductase into 6 thermodynamically distinct classes. there are apparently 4 classes of heme c553, with em7-values of 295 mv, 10 mv, -190 mv and -390 mv, present in a stoichiometry of 1:1:2:1; two equivalents of heme c559, em7 o mv, and one of heme p-460, an unusual chromophore, with em7 -260 mv.19836628687
proton electrochemical gradients in washed cells of nitrosomonas europaea and nitrobacter agilis.the components of the proton motive force (deltap), namely, membrane potential (deltapsi) and transmembrane ph gradient (deltaph), were determined in the nitrifying bacteria nitrosomonas europaea and nitrobacter agilis. in these bacteria both deltapsi and deltaph were dependent on external ph. thus at ph 8.0, nitrosomonas europaea and nitrobacter agilis had deltapsi values of 173 mv and 125 mv (inside negative), respectively, as determined by the distribution of the lipophilic cation [(3)h]tetra ...19836833187
co-binding c-type cytochromes and a high-potential cytochrome c in nitrosomonas europaea.the purification of two soluble co-binding cytochromes c from nitrosomonas europaea is described. cytochrome cco-550 ran on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis with an apparent mr of 32 000, whereas for cytochrome cco-552 the apparent mr was 16 000. redox potentials (em, 7) were determined as +140 and -50mv respectively. cytochrome cco-550 was co-purified with a cytochrome c-553, for which an unusually high redox potential of +450mv was measured. these latter components we ...19836307283
heme p460 of hydroxylamine oxidoreductase of nitrosomonas. reaction with co and h2o2.hydroxylamine oxidoreductase (hao) of nitrosomonas catalyzes the dehydrogenation of nh2oh and subsequent addition of oxygen to form nitrite. hao contains c hemes and the co-binding heme p460 in a 7:1 ratio; dehydrogenation of nh2oh involves passage of electrons to p460 and then c hemes. we now report that electrons rapidly pass from c hemes of hao to the p460 center and then to h2o2. this conclusion is supported by (a) inhibition of c heme oxidation with co and (b) loss of h2o2-oxidizability of ...19836861765
methane oxidation by nitrosomonas europaea.methane inhibited nh4+ utilization by nitrosomonas europaea with a ki of 2mm. o2 consumption was not inhibited. in the absence of nh4+, or with hydrazine as reductant, methane caused nearly a doubling in the rate of o2 uptake. the stimulation was abolished by allylthiourea, a sensitive inhibitor of the oxidation of nh4+. analysis revealed that methanol was being formed in these experiments, with yields approaching 1 mol of methanol per mol of o2 consumed under certain conditions. when cells were ...19836870854
3,3',5,5'-tetramethylbenzidine/h2o2 staining is not specific for heme proteins separated by gel electrophoresis.staining of sodium dodecyl sulfate or lithium dodecyl sulfate gels with 3,3',5,5'-tetramethylbenzidine (tmbz)/h2o2 after electrophoresis has frequently been used as a specific method of detecting heme proteins. that tmbz is an electron donor for o2 reduction by the nonheme-soluble cytochrome oxidase/nitrite reductase from nitrosomonas europaea is now shown; this protein is detected by the tmbz/h2o2 method. a method for the determination of tmbz oxidase activity is given; hence, the detection of ...19846207749
mössbauer, epr, and optical studies of the p-460 center of hydroxylamine oxidoreductase from nitrosomonas. a ferrous heme with an unusually large quadrupole splitting.hydroxylamine oxidoreductase from nitrosomonas europeae catalyzes the oxidative conversion of nh2oh to no-2. the enzyme, mr = 220,000, has an (alpha beta)3 subunit structure with each alpha beta subunit containing 7-8 c-type hemes and one unusual prosthetic group, termed p-460. the p-460 is also found in a mr approximately equal to 17,000 protein (p-460 fragment). mössbauer spectra of the reduced p-460 groups, in hydroxylamine oxidoreductase and the fragment, exhibit nearly identical quadrupole ...19846327697
hybrid biosensor for clinical and fermentation process control. 19846596903
na+ and k+ transport in nitrosomonas europaea and nitrobacter agilis.potassium-depleted cells of nitrosomonas europaea and nitrobacter agilis were prepared by diethanolamine treatment and contained less than 5 mm intracellular k+. the addition of k+ to k+-depleted cells of n. europaea and n. agilis resulted in a depolarization of membrane potential (delta psi) by about 5 and 10 mv, respectively. this depolarization was, however, compensated by an equivalent increase in transmembrane ph gradient (delta ph), so that the total proton-motive force (delta p) remained ...19846733088
kinetics of reduction by substrate or dithionite and heme-heme electron transfer in the multiheme hydroxylamine oxidoreductase.hydroxylamine oxidoreductase of nitrosomonas catalyzes the dehydrogenation of nh2oh. it contains hemes c553, c559 and p460 in the ratio 5:2:1. at equilibrium four or five c hemes are reduced by nh2oh or nh2nh2, respectively. heme p460 is the site of electron entry into the enzyme; electrons exit via p460 to o2 or h2o2 with rate constants of 30s-1. we report that hydroxylamine oxidoreductase has two categories of electron-accepting sites: (a) heme p460, an h2o2-sensitive site, which is reactive w ...19846745259
diheme cytochrome c-554 from nitrosomonas. soret resonance raman indication of an unusual ferric 5-coordinate structure.the diheme cytochrome c-554 which participates in ammonia oxidation in the chemoautotroph , nitrosomonas europaea has been studied by soret excitation resonance raman spectroscopy. the raman spectrum of reduced cytochrome c-554 at neutral ph is similar classical 6-coordinate low-spin ferrous mammalian cytochrome c. in contrast, the spectrum of ferric cytochrome c-554 suggests a 5-coordinate state which is unusual for c hemes. the oxidized spectrum closely resemble that of horseradish peroxidase ...19846327385
bicarbonate uptake by nitrifiers: effects of growth rate, ph, substrate concentration, and metabolic inhibitors.the ratios of bicarbonate uptake to substrate oxidation were measured for three genera of nitrifying bacteria. the ratios for the two ammonium oxidizers tested were essentially the same; 0.0863 +/- 0.0055 and 0.0868 +/- 0.0091 mumol of bicarbonate were taken up per umol ammonium oxidized for nitrosomonas europaea and a nitrosospira strain, respectively. for nitrobacter sp., a ratio of 0.0236 +/- 0.0013 mumol of bicarbonate taken up per umol of nitrite oxidized was obtained. cells were grown in s ...198416346673
tropospheric sources of nox: lightning and biology.laboratory experiments to quantify the global production of nox (no + no2) in the troposphere due to atmospheric lightning and biogenic activity in soil are presented. these laboratory experiments, as well as other studies, suggest that the global production of nox by lightning probably ranges between 2 and 20 mt(n)y-1 of no and is strongly dependent on the total energy deposited by lightning, a quantity not well-known. in our laboratory experiments, nitrifying micro-organisms is soil were fou ...198411540827
test medium for the growth of nitrosomonas europaea.a mineral medium for studying the growth of nitrosomonas europaea was developed and examined. the medium was defined in terms of chemical speciation by using chemical equilibrium computer models. the medium significantly increased the metabolic activity of the organisms compared with previously developed media, yielding a specific growth rate as high as 3.0 day (generation time, 5.5 h). the specific growth rate was enhanced by increasing the inoculum and was linearly correlated with the inoculum ...198516346783
n kinetic analysis of n(2)o production by nitrosomonas europaea: an examination of nitrifier denitrification.a series of n isotope tracer experiments showed that nitrosomonas europaea produces nitrous oxide only under oxygen-limiting conditions and that the labeled n from nitrite, but not nitrate, is incorporated into nitrous oxide, indicating the presence of the "denitrifying enzyme" nitrite reductase. a kinetic analysis of the m/z 44, 45, and 46 nitrous oxide produced by washed cell suspensions of n. europaea when incubated with 4 mm ammonium (99% n) and 0.4 mm nitrite (99% n) was performed. no label ...198516346787
nitrite and nitrous oxide production by methylosinus trichosporium.conditions for the production of nitrite and nitrous oxide by an obligate methanotroph, methylosinus trichosporium (ob 3b), were studied. the rate of nitrite production (v no2-) was correlated with the concentration of ammonia up to 20 mm in the presence of sufficient amounts of oxygen and inversely correlated with the amounts of methane in the system. the rate of nitrous oxide (n2o) production (v n2o) was correlated positively with v no2- and the amount of nitrite produced and inversely with th ...19853921227
suicidal inactivation and labelling of ammonia mono-oxygenase by acetylene.acetylene brings about a progressive inactivation of ammonia mono-oxygenase, the ammonia-oxidizing enzyme in nitrosomonas europaea. high nh4+ ion concentrations were protective. the inactivation followed first-order kinetics, with a rate constant of 1.5 min-1 at saturating concentrations of acetylene. if acetylene was added in the absence of o2, the cells remained active until o2 was re-introduced. a protective effect was also demonstrated with thiourea, a reversible non-competitive inhibitor of ...19854004794
spectroscopic evidence for a photosensitive oxygenated state of ammonia mono-oxygenase.photoinactivation of ammonia oxidation by nitrosomonas europaea cells by near-u.v. light was confirmed and further shown to occur with the same rate constant as loss of bromoethane-oxidation activity. hydroxylamine oxidation was much less photosensitive. protection against inactivation was afforded by anaerobiosis, organic substrates of ammonia mono-oxygenase such as bromoethane, or metal-ion-chelating agents such as thiourea. the presence of 10 mm-nh4+ or 1 mm-hydroxylamine made little differen ...19853922353
deoxyribonucleic acid homologies among 96 strains of ammonia-oxidizing bacteria.dna of 96 strains of the genera nitrosomonas, nitrosococcus, nitrosospira, nitrosolobus, and nitrosovibrio was isolated and analysed spectrophotometrically. percentages of guanine plus cytosine (g + c) content, genome sizes, and dna-dna homologies were determined. the results indicated the presence of eight nitrosomonas species, three or four nitrosococcus species, five nitrosospira species, and two species of both nitrosolobus and nitrosovibrio. dna homologies between strains of a separate spec ...19854004447
a comparative survey of several bacterial aa3-type cytochrome c oxidases.the aa3-type cytochrome c oxidases purified from nitrobacter agilis, thiobacillus novellus, nitrosomonas europaea, and pseudomonas am 1 were compared. they have haem a and copper atom as the prosthertic groups and show alpha and gamma absorption peaks at around 600 and 440 nm, respectively. each oxidase molecule is composed of two kinds of subunits. the n. agilis oxidase has 2 moles of haem a and 2 atoms of copper in the minimal structural unit composed of one molecule each of the two kinds of s ...19852991467
tetraheme cytochrome c-554 from nitrosomonas europaea. heme-heme interactions and ligand binding.cytochrome c-554 functions in the ammonia oxidizing system of nitrosomonas europaea. we have investigated its molecular and ligand binding properties and studied the protein with optical, epr, and mössbauer spectroscopies in the ph range from 2 to 13. amino acid, heme, and metal analyses show that the protein has mr = 25,000 and that it contains four c-type hemes per molecule. optical spectra reveal that the heme ligand structures are sensitive to the ph of the medium and that the hemes can bind ...19863003055
n-terminal amino acid sequence of cytochrome c-552 from nitrosomonas europaea.nitrosomonas europaea is an ammonia-oxidizing bacterium which contains multiple c-type cytochromes. few of these components have been assigned physiological roles, but on the basis of molecular weight and redox potential cytochrome c-552 has been considered to be an analogue of the mitochondrial cytochrome-c family of proteins. we present the n-terminal amino acid sequence (47 residues) of cytochrome c-552 and show that this protein is most closely related to the group of small cytochrome-c comp ...19863004498
cytochrome aa3 from nitrosomonas europaea.cytochrome c oxidase has been purified from the ammonia oxidizing chemoautotroph nitrosomonas europaea by ion-exchange chromatography in the presence of triton x-100. the enzyme has absorption maxima at 420 and 592 nm in the resting state and at 444 and 598 nm in the dithionite-reduced form; optical extinction coefficient (598 nm minus 640 nm) = 21.9 cm-1 nm-1. the enzyme has approximately 11 nmol of heme a and approximately 11 nmol of copper per mg of protein (lowry procedure). there appear to ...19863023381
inhibition of ammonium oxidation by nitrapyrin in soil and liquid culture.inhibition of growth of axenic cultures of nitrosomonas europaea by nitrapyrin was investigated in liquid culture and in soil. in liquid culture, exponentially growing cells were more sensitive than stationary-phase cells, possibly due to a requirement for uptake of nitrapyrin, metabolism of nitrapyrin, or both before inhibition. differences in sensitivity were observed between the parent strain and two strains, sp1 and sp2, that were selected through repeated subculturing. these differences wer ...198616347171
dinitrogen production from nitrite by a nitrosomonas isolate.a chemolithotrophic ammonium-oxidizing bacterium that was able to reduce no(2) to n(2) (m/z 30) while oxidizing ammonium under conditions of oxygen stress was isolated from stream sediments. energy was derived from ammonium oxidation, as evidence by growth, with co(2) serving as the sole c source. the organism was a gram-negative, motile, short rod that failed to grow either aerobically or anaerobically in heterotroph media. the organism was identified as a nitrosomonas sp.198616347192
nitrifying bacteria in wastewater reservoirs.deep wastewater reservoirs are used throughout israel to store domestic wastewater effluents for summer irrigation. these effluents contain high concentrations of ammonia (</=5 mm) that are frequently toxic to photosynthetic microorganisms and that lead to development of anoxic conditions. population dynamics of nitrifying bacteria and rates of nitrification were studied in two wastewater reservoirs that differed in organic load and degree of oxygenation and in the laboratory under controlled co ...198716347319
conformational change accompanies redox reactions of the tetraheme cytochrome c-554 of nitrosomonas europaea.cytochrome c-554 of the ammonia-oxidizing chemolithoautotropic bacteria is thought to mediate electron transfer from hydroxylamine oxidoreductase to a terminal oxidase and/or to ammonia monooxygenase. the cytochrome has four c hemes which interact magnetically and have the same redox potential. we report that the kinetics of reduction of ferric cytochrome c-554 by dithionite or the oxidation of ferrous cytochrome c-554 by o2 or h2o2 are complex and multiphasic. transient rapid-scan difference sp ...19873026805
[biology of chemoautotrophs]. 19883150584
catalytic properties of cytochrome c oxidase purified from nitrosomonas europaea.cytochrome c oxidase of nitrosomonas europaea reacts with not only the native cytochrome c (n. europaea cytochrome c-552) but also horse and yeast cytochromes c. the effects on its reactivity of various reagents were very different between the reactions with the native and eukaryotic cytochromes c as the electron donors. the oxidation of eukaryotic ferrocytochrome c by the oxidase was activated by addition of anionic detergents such as sodium dodecyl sulfate and sodium cholate, and anionic phosp ...19882839468
effect of solvent, pressure and temperature on reaction rates of the multiheme hydroxylamine oxidoreductase. evidence for conformational change.hydroxylamine oxidoreductase (hao) of the ammonia-oxidizing bacterium nitrosomonas catalyzes the oxidation: nh2oh + h2o----hno2 + 2e- + 2 h+. the heme-like chromophore p460 is part of a site which binds substrate, extracts electrons and then passes them to the many c hemes of the enzyme. reduction of the c hemes by hydroxylamine is biphasic with apparent first-order rate constants k1 and k2. co binds to ferrous p460 with apparent first-order rate constants, k1,co. in this work we have measured t ...19883416874
interaction of ammonia monooxygenase from nitrosomonas europaea with alkanes, alkenes, and alkynes.ammonia monooxygenase of nitrosomonas europaea catalyzes the oxidation of alkanes (up to c(8)) to alcohols and alkenes (up to c(5)) to epoxides and alcohols in the presence of ammonium ions. straight-chain, n-terminal alkynes (up to c(10)) all exhibited a time-dependent inhibition of ammonia oxidation without effects on hydrazine oxidation.198816347810
effects of light and co on the survival of a marine ammonium-oxidizing bacterium during energy source deprivation.the chemolithotrophic ammonium-oxidizing bacterium nitrosomonas cryotolerans responds uniquely to nutrient deprivation by lowering its endogenous respiration and anabolic processes to undetectable levels during starvation, thus appearing to enter a dormant state. to ascertain whether this state protects the cells from further stresses (as seen with endospore-forming bacteria), the starved cells were subjected to two known inhibitors, co and light. it was found that long-term-starved cells were l ...198816347787
simultaneously occurring nitrification and denitrification under oxygen gradient by polyelectrolyte complex-coimmobilized nitrosomonas europaea and paracoccus denitrificans cells. 198818584619
nitrosovibrio spp., the dominant ammonia-oxidizing bacteria in building sandstone.in five historical buildings in the federal republic of germany, ammonia-oxidizing bacteria of the genera nitrosovibrio, nitrosospira, and nitrosomonas were detected in high cell numbers. in building stones, nitrosovibrio was the most abundant ammonia-oxidizing organism. in the soil at the foot of each building, nitrosomonas spp. were the most common ammonia oxidizers, whereas nitrosovibrio spp. were not detected.198916348002
an analysis of nitrification during the aerobic digestion of secondary sludges.investigations were undertaken to study the occurrence and progress of nitrification during aerobic digestion of activated sludge in a wide range of initial concentrations of total solids (1000 to 80 000 mg litre(-1), initial ph range of 4.5 to 10.4 and digestion temperature range of 5 degrees to 60 degrees c. batch aerobic digestion studies on activated sludge grown on wastewater (enriched with organic solids from human excretal material) indicate that almost complete elimination of the 'biodeg ...198915092439
degradation of trichloroethylene by the ammonia-oxidizing bacterium nitrosomonas europaea.suspensions of nitrosomonas europaea are shown to cause the complete disappearance of 10 microm trichloroethylene at rates of 1 microm mg protein-1. the reaction continues at nearly this rate for many hours. fresh cells catalyze the reaction in the absence of added ammonium (presumably utilizing endogenous ammonia or stored reductant). in older cells, trichloroethylene degradation depends on the addition of ammonia. acetylene, 2-chloro 6-trichloromethylpyridine and alpha alpha'dipyridyl, which i ...19892930535
some properties of nitrosomonas europaea cytochrome c oxidase (aa3-type) which lacks cua.from nitrosomonas europaea which had been cultivated in a medium deficient in copper, cytochrome c oxidase (aa3-type) which did not have cua was purified. the oxidase did not show the 830-nm peak and its esr spectrum differed greatly from that of the normal enzyme, which has two copper atoms, cua and cub, per molecule. however, the oxidase which did not have cua showed almost the same cytochrome c oxidizing activity as the normal oxidase.19892542236
detection and analysis of two serotypes of ammonia-oxidizing bacteria in sewage plants by flow cytometry.two different serotypes of the genus nitrosomonas were isolated from samples of the sewage plant heidelberg. these nitrifiers were enumerated in activated sludge of various other sewage plants after immunofluorescent labeling and staining with propidium iodide by flow cytometry. the concentrations of these serotypes of nitrosomonas spp. were in the range of 0.1 to 2%. also, a test for the determination of the activity of ammonia-oxidizing bacteria was developed. nitrite-oxidizing bacteria were s ...19902403253
oxidation of monohalogenated ethanes and n-chlorinated alkanes by whole cells of nitrosomonas europaea.we have investigated the substrate specificity of ammonia monooxygenase in whole cells of the nitrifying bacterium nitrosomonas europaea for a number of aliphatic halogenated hydrocarbons. to determine the effect of the halogen substituent and carbon chain length on substrate reactivity, we measured the rates of oxidation of the monohalogenated ethanes (fluoroethane, chloroethane, bromoethane, and iodoethane) and n-chlorinated c1 to c4 alkanes by whole cells of n. europaea. for monohalogenated e ...19902394686
degradation of halogenated aliphatic compounds by the ammonia- oxidizing bacterium nitrosomonas europaea.suspensions of nitrosomonas europaea catalyzed the ammonia-stimulated aerobic transformation of the halogenated aliphatic compounds dichloromethane, dibromomethane, trichloromethane (chloroform), bromoethane, 1,2-dibromoethane (ethylene dibromide), 1,1,2-trichloroethane, 1,1,1-trichloroethane, monochloroethylene (vinyl chloride), gem-dichloroethylene, cis- and trans-dichloroethylene, cis-dibromoethylene, trichloroethylene, and 1,2,3-trichloropropane, tetrachloromethane (carbon tetrachloride), te ...19902339874
ammonia-oxidizing bacteria in a chloraminated distribution system: seasonal occurrence, distribution and disinfection resistance.nitrification in chloraminated drinking water can have a number of adverse effects on water quality, including a loss of total chlorine and ammonia-n and an increase in the concentration of heterotrophic plate count bacteria and nitrite. to understand how nitrification develops, a study was conducted to examine the factors that influence the occurrence of ammonia-oxidizing bacteria (aob) in a chloraminated distribution system. samples were collected over an 18-month period from a raw-water sourc ...19902306090
the small-scale production of [u-14c]acetylene from ba14co3: application to labeling of ammonia monooxygenase in autotrophic nitrifying bacteria.a small-scale method has been adapted from an established procedure for the generation of [u-14c]acetylene from inexpensive and commonly available precursors. the method involves the fusing of ba14co3 with excess barium metal to produce ba14c2. the bac2 is reacted with water to generate acetylene which is then selectively dissolved into dimethyl sulfoxide (dmso). the results presented demonstrate the effect of ba:baco3 ratio on the concentrations of various gases released during the hydrolysis r ...19902291478
cytochrome p-460 of nitrosomonas europaea: further purification and further characterization.cytochrome p-460 of nitrosomonas europaea [erickson, r.h. and hooper, a.b. (1972) biochim. biophys. acta 275, 231-244] was further purified to an electrophoretically homogeneous state. the cytochrome molecule was composed of three molecules of subunits with mr of 17,300-18,500, and contained three atoms of iron, which seemed to be heme iron, and six cysteine residues, but did not contain nonheme iron or inorganic sulfide. the cytochrome showed absorption peaks at 460 and 688 nm with a broad shou ...19902089033
inhibition of ammonia monooxygenase in nitrosomonas europaea by carbon disulfide.carbon disulfide has long been recognized as a potent inhibitor of nitrification, and it is the likely active component in several nitrification inhibitors suitable for field use. the effects of this compound on nitrosomonas europaea have been investigated, and the site of action has been determined. low concentrations of cs2 (less than 400 microm) produced a time-dependent inhibition of ammonia-dependent o2 uptake but did not inhibit hydrazine-oxidizing activity. cs2 also produced distinct chan ...19902118501
biodegradation of halogenated hydrocarbon fumigants by nitrifying bacteria.three species of nitrifying bacteria were tested for the ability to degrade the halocarbon fumigants methyl bromide, 1,2-dichloropropane, and 1,2-dibromo-3-chloropropane. the soil nitrifiers nitrosomonas europaea and nitrosolobus multiformis degraded all three fumigants, while the marine nitrifier nitrosococcus oceanus degraded only methyl bromide under the conditions tested. inhibition of biodegradation by allylthiourea and acetylene, specific inhibitors of ammonia monooxygenase, suggests that ...199016348264
competition for ammonium between nitrifying and heterotrophic bacteria in dual energy-limited chemostats.the absence of nitrification in soils rich in organic matter has often been reported. therefore, competition for limiting amounts of ammonium between the chemolithotrophic ammonium-oxidizing species nitrosomonas europaea and the heterotrophic species arthrobacter globiformis was studied in the presence of nitrobacter winogradskyi in continuous cultures at dilution rates of 0.004 and 0.01 h. ammonium limitation of a. globiformis was achieved by increasing the glucose concentration in the reservoi ...199116348588
factors limiting aliphatic chlorocarbon degradation by nitrosomonas europaea: cometabolic inactivation of ammonia monooxygenase and substrate specificity.the soil nitrifying bacterium nitrosomonas europaea is capable of degrading trichloroethylene (tce) and other halogenated hydrocarbons. tce cometabolism by n. europaea resulted in an irreversible loss of tce biodegradative capacity, ammonia-oxidizing activity, and ammonia-dependent o(2) uptake by the cells. inactivation was not observed in the presence of allylthiourea, a specific inhibitor of the enzyme ammonia monooxygenase, or under anaerobic conditions, indicating that the tce-mediated inact ...199116348568
protection of nitrosomonas europaea colonizing clay minerals from inhibition by nitrapyrin.nitrate production by nitrosomonas europaea in inorganic liquid medium containing ammonium was limited by reduction in ph. in the presence of montmorillonite and vermiculite, expanding clays with high cation-exchange-capacity (cec), nitrite yield was increased, ammonia oxidation continued at ph values below those which inhibited growth in the absence of clays and growth was biphasic. the first phase was similar to that in the absence of clays, while the second was characterized by a lower rate o ...19911955871
quantitative structure-activity relationships for chemical toxicity to environmental bacteria.quantitative structure-activity relationships (qsars) were developed for nonreactive chemical toxicity to each of four groups of bacteria of importance in environmental engineering: aerobic heterotrophs, methanogens, nitrosomonas, and microtox. the qsars were based on chemicals covering a range of structures and including important environmental pollutants (i.e., chlorinated and other substituted benzenes, phenols, and aliphatic hydrocarbons). qsars were developed for each chemical class and for ...19911769352
p460 of hydroxylamine oxidoreductase of nitrosomonas europaea: soret resonance raman evidence for a novel heme-like structure.p460, an iron-containing chromophore at the active site of hydroxylamine oxidoreductase of the ammonia-oxidizing bacterium nitrosomonas europaea, is a macrocycle of unknown structure with a soret-like 460-nm absorption band in the ferrous form. the pigment can also be isolated in a peptide, "p460-fragment". resonance raman spectroscopy (lambda ex = 457.9 nm) suggests that p460 is a new type of heme with symmetry properties lower than those of protophorphyrin ix or chlorins and similar to those o ...19911989613
c-cytochromes of the ammonia-oxidizing chemolithoautotrophic bacteria. 19911646009
spectroscopic and rapid kinetic studies of reduction of cytochrome c554 by hydroxylamine oxidoreductase from nitrosomonas europaea.during oxidation of hydroxylamine, hydroxylamine oxidoreductase (hao) transfers two electrons to tetraheme cytochrome c554 at rates sufficient to account for physiological rates of oxidation of ammonia to nitrite in nitrosomonas europaea. spectroscopic changes indicate that the two electrons are taken up by a high-potential pair of hemes (e degrees' = +47 mv) (one apparently high spin and one low spin). during single-turnover experiments, in which the reduction of oxidized cytochrome c554 by nh2 ...19911660304
crystallization and preliminary x-ray studies of hydroxylamine oxidoreductase from nitrosomonas europaea.hydroxylamine oxidoreductase [ec 1.7.3.4] from nitrosomonas europaea was crystallized by the microdialysis method using ammonium sulfate. its space group is p63 with cell dimensions of a = b = 96.4 a and c = 266.2 a. its molecular weight was determined to be 190,000-195,000 by the x-ray small angle scattering and ultracentrifugal methods.19911783597
resolution of the four hemes of cytochrome c554 from nitrosomonas europaea by redox potentiometry and optical spectroscopy.the electrochemical behavior of tetraheme cytochrome c554 from nitrosomonas europaea has been studied by thin-layer spectroelectrochemistry, cyclic voltammetry, differential pulse voltammetry, and alternating current voltammetry. three redox couples were detected. midpoint potentials for the high-m intermediate-, and low-potential couples are +47, -147, and -276 mv, respectively, from the spectroelectrochemical measurements and +50, -120, and -225 mv, respectively, from the voltammetry measureme ...19911660303
14c2h2- and 14co2-labeling studies of the de novo synthesis of polypeptides by nitrosomonas europaea during recovery from acetylene and light inactivation of ammonia monooxygenase.incubation of cells of the nitrifying bacterium nitrosomonas europaea with 14c2h2 results in the covalent attachment of 14c label to a membrane-bound polypeptide of an approximate mr of 28,000 (hyman, m.r., and wood, p.m. (1985) biochem. j. 227, 719-725). a labeling procedure using 14c2h2 generated from ba14co3 has been used to investigate the correlation between the extent of covalent modification of this polypeptide by 14c from 14c2h2 and the level of ammonia oxidizing activity in whole cells. ...19921730700
acceleration of the oxygen reaction in cua-deficient nitrosomonas europaea cytochrome c oxidase as revealed by the flow-flash measurement.the oxygen reaction of nitrosomonas europaea cytochrome c oxidase containing either 2cu or 1cu per two heme a molecules was investigated by the flow-flash technique at 20 degrees c. the reaction profiles of the bacterial enzyme were essentially the same as those of bovine heart cytochrome c oxidase, although the rate of the primary oxygen compound formation was much slower. the 1cu enzyme exhibited higher rates for both primary oxygen compound formation and intramolecular electron transfer than ...19921311570
effects of grazing by flagellates on competition for ammonium between nitrifying and heterotrophic bacteria in chemostats.the enhanced mineralization of organic nitrogen by bacteriophagous protozoa is thought to favor the nitrification process in soils, in which nitrifying bacteria have to compete with heterotrophic bacteria for the available ammonium. to obtain more insight into this process, the influence of grazing by the bacteriovorous flagellate adriamonas peritocrescens on the competition for limiting amounts of ammonium between the ammonium-oxidizing species nitrosomonas europaea and the heterotrophic specie ...199216348722
oxidation of nitrapyrin to 6-chloropicolinic acid by the ammonia-oxidizing bacterium nitrosomonas europaea.suspensions of nitrosomonas europaea catalyzed the oxidation of the commercial nitrification inhibitor nitrapyrin [2-chloro-6-(trichloromethyl)-pyridine]. rapid oxidation of nitrapyrin (at a concentration of 10 mum) required the concomitant oxidation of ammonia, hydroxylamine, or hydrazine. the turnover rate was highest in the presence of 10 mm ammonia (0.8 nmol of nitrapyrin per min/mg of protein). the product of the reaction was 6-chloropicolinic acid. by the use of o(2), it was shown that one ...199216348740
competition for ammonium between nitrifying and heterotrophic bacteria in continuously percolated soil columns.although the absence of nitrate formation in grassland soils rich in organic matter has often been reported, low numbers of nitrifying bacteria are still found in these soils. to obtain more insight into these observations, we studied the competition for limiting amounts of ammonium between the chemolithotrophic ammonium-oxidizing species nitrosomonas europaea and the heterotrophic species arthrobacter globiformis in the presence of nitrobacter winogradskyi with soil columns containing calcareou ...199216348787
selective inhibition of ammonium oxidation and nitrification-linked n(2)o formation by methyl fluoride and dimethyl ether.methyl fluoride (ch(3)f) and dimethyl ether (dme) inhibited nitrification in washed-cell suspensions of nitrosomonas europaea and in a variety of oxygenated soils and sediments. headspace additions of ch(3)f (10% [vol/vol]) and dme (25% [vol/vol]) fully inhibited no(2) and n(2)o production from nh(4) in incubations of n. europaea, while lower concentrations of these gases resulted in partial inhibition. oxidation of hydroxylamine (nh(2)oh) by n. europaea and oxidation of no(2) by a nitrobacter s ...199316349011
quantitative determination of the spatial distribution of nitrosomonas europaea and nitrobacter agilis cells immobilized in kappa-carrageenan gel beads by a specific fluorescent-antibody labelling technique.a novel technique, combining labelling and stereological methods, for the determination of spatial distribution of two microorganisms in a biofilm is presented. cells of nitrosomonas europaea (atcc 19718) and nitrobacter agilis (atcc 14123) were homogeneously distributed in a kappa-carrageenan gel during immobilization and allowed to grow out to colonies. the gel beads were sliced in thin cross sections after fixation and embedding. a two-step labelling method resulted in green fluorescent colon ...199316348970
effects of grazing by flagellates on competition for ammonium between nitrifying and heterotrophic bacteria in soil columns.the enhanced mineralization of immobilized nitrogen by bacteriophagous protozoa has been thought to favor the nitrification process in soils in which nitrifying bacteria must compete with heterotrophic bacteria for the available ammonium. to obtain more insight into this process, the influence of grazing by the flagellate adriamonas peritocrescens on the competition for ammonium between the chemolithotrophic species nitrosomonas europaea and the heterotrophic species arthrobacter globiformis in ...199316348988
inhibition of ammonia oxidation in nitrosomonas europaea by sulfur compounds: thioethers are oxidized to sulfoxides by ammonia monooxygenase.organic sulfur compounds are well-known nitrification inhibitors. the inhibitory effects of dimethylsulfide, dimethyldisulfide, and ethanethiol on ammonia oxidation by nitrosomonas europaea were examined. both dimethylsulfide and dimethyldisulfide were weak inhibitors of ammonia oxidation and exhibited inhibitory characteristics typical of substrates for ammonia monooxygenase (amo). depletion of dimethylsulfide required o(2) and was prevented with either acetylene or allylthiourea, two inhibitor ...199316349086
mechanism-based inactivation of ammonia monooxygenase in nitrosomonas europaea by allylsulfide.allylsulfide caused an irreversible inactivation of ammonia monooxygenase (amo) activity (ammonia-dependent o(2) uptake) in nitrosomonas europaea. the hydroxylamine oxidoreductase activity (hydrazine-dependent o(2) uptake) of cells was unaffected by allylsulfide. anaerobic conditions or the presence of allylthiourea, a reversible noncompetitive amo inhibitor, protected amo from inactivation by allylsulfide. ammonia did not protect amo from inactivation by allylsulfide but instead increased the r ...199316349087
kinetic studies of ammonia monooxygenase inhibition in nitrosomonas europaea by hydrocarbons and halogenated hydrocarbons in an optimized whole-cell assay.the inhibitory effects of 15 hydrocarbons and halogenated hydrocarbons on nh(3) oxidation by ammonia monooxygenase (amo) in intact cells of the nitrifying bacterium nitrosomonas europaea were determined. determination of amo activity, measured as no(2) production, required coupling of hydroxylamine oxidoreductase (hao) activity with nh(3)-dependent nh(2)oh production by amo. hydrazine, an alternate substrate for hao, was added to the reaction mixtures as a source of reductant for amo. most inhib ...199316349014
a comparison of no and n2o production by the autotrophic nitrifier nitrosomonas europaea and the heterotrophic nitrifier alcaligenes faecalis.soil microorganisms are important sources of the nitrogen trace gases no and n2o for the atmosphere. present evidence suggests that autotrophic nitrifiers such as nitrosomonas europaea are the primary producers of no and n2o in aerobic soils, whereas denitrifiers such as pseudomonas spp. or alcaligenes spp. are responsible for most of the no and n2o emissions from anaerobic soils. it has been shown that alcaligenes faecalis, a bacterium common in both soil and water, is capable of concomitant he ...19938285659
reductive dehalogenation of the trichloromethyl group of nitrapyrin by the ammonia-oxidizing bacterium nitrosomonas europaea.suspensions of nitrosomonas europaea catalyzed the reductive dehalogenation of the commercial nitrification inhibitor nitrapyrin (2-chloro-6-trichloromethylpyridine). the product of the reaction was identified as 2-chloro-6-dichloromethylpyridine by its mass fragmentation and nuclear magnetic resonance spectra. a small amount of 2-chloro-6-dichloromethylpyridine accumulated during the conversion of nitrapyrin to 6-chloropicolinic acid in an aerated solution in the presence of ammonia (t. vannell ...19938285668
evidence for the structure of the active site heme p460 in hydroxylamine oxidoreductase of nitrosomonas.hydroxylamine oxidoreductase (hao) is responsible for the oxidation of hydroxylamine to nitrite in nitrification by nitrosomonas europaea. it has an alpha n subunit structure and eight covalently bound hemes per subunit. seven of these have visible spectra indistinguishable from heme c. the eighth, designated as p460, has unusual visible spectroscopic features in the enzyme and in a heme-containing proteolytic fragment. its structure has not been previously determined. enzymatic digestions of ha ...19938369308
the phylogeny of autotrophic ammonia-oxidizing bacteria as determined by analysis of 16s ribosomal rna gene sequences.partial sequences of the 16s ribosomal rna genes of eleven autotrophic ammonia-oxidizing bacteria were determined by pcr amplification from small amounts of heat-lysed biomass followed by direct sequencing of pcr products. the sequences were aligned with those of representative proteobacteria and phylogenetic trees inferred using both parsimony and distance matrix methods. this confirmed that the autotrophic ammonia-oxidizers comprise two major lines of descent within the proteobacteria. nitroso ...19937689633
hydroxylamine oxidoreductase from nitrosomonas europaea is a multimer of an octa-heme subunit.a fully active form of hydroxylamine oxidoreductase from nitrosomonas has been purified with high recovery and shown by reverse-phase high performance liquid chromatography and n-terminal analysis to contain only a 63-kda subunit and to lack the 11-kda protein previously thought to be a second subunit. based on the previously published values of molecular weight in solution, hydroxylamine oxidoreductase probably has an alpha 2 or alpha 3 oligomeric structure. the enzyme was digested separately w ...19938325841
optical spectropotentiometric resolution of the hemes of hydroxylamine oxidoreductase. heme quantitation and ph dependence of em.the hemes of hydroxylamine oxidoreductase (hao) have been analyzed optically by potentiometric titrations using a low volume optically transparent thin layer electrochemical cell. the electrochemical behavior of the hao monomeric unit has been interpreted by modeling the spectroelectrochemical data at several wavelengths to eight one-electron nernst sites: seven c-type hemes and one p460 heme. of the seven c-hemes, six show alpha-bands with absorption maxima at or near 553 nm. one c-heme has an ...19938325842
an electrophoretic study of the thermal- and reductant-dependent aggregation of the 27 kda component of ammonia monooxygenase from nitrosomonas europaea.standard protocols for sample preparation for sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) typically involve the combined use of heat and a reductant to fully disrupt protein-protein interactions and allow for constant ratios of sds-binding to individual polypeptides. however, 14c-labeled forms of the membrane-bound, active-site-containing 27 kda polypeptide of ammonia monooxygenase from nitrosomonas europaea undergo an aggregation reaction when cells or membranes are hea ...19938375353
multiple copies of genes coding for electron transport proteins in the bacterium nitrosomonas europaea.the genome of nitrosomonas europaea contains at least three copies each of the genes coding for hydroxylamine oxidoreductase (hao) and cytochrome c554. a copy of an hao gene is always located within 2.7 kb of a copy of a cytochrome c554 gene. cytochrome p-460, a protein that shares very unusual spectral features with hao, was found to be encoded by a gene separate from the hao genes.19938385668
simultaneous nitrification and denitrification using immobilized microorganisms.nitrogen removal from wastewaters is a multiple step process in which nitrification is often a problem due to the slow growth rates of the nitrifying bacteria. by immobilization of these bacteria, nitrification can be efficiently accomplished in compact reactors. in this paper, the possibilities of integrated nitrification and denitrification within a single reactor system are evaluated. two main systems are studied: a) nitrosamines europaea and pseudomonas denitrificans co-immobilized in a a ge ...19938399972
in vitro activation of ammonia monooxygenase from nitrosomonas europaea by copper.the effect of copper on the in vivo and in vitro activity of ammonia monooxygenase (amo) from the nitrifying bacterium nitrosomonas europaea was investigated. the addition of cucl2 to cell extracts resulted in 5- to 15-fold stimulation of ammonia-dependent o2 consumption, ammonia-dependent nitrite production, and hydrazine-dependent ethane oxidation. amo activity was further stimulated in vitro by the presence of stabilizing agents, including serum albumins, spermine, or mgcl2. in contrast, the ...19938458839
sequence of the gene coding for ammonia monooxygenase in nitrosomonas europaea.nitrosomonas europaea, a chemolithotrophic bacterium, was found to contain two copies of the gene coding for the presumed active site polypeptide of ammonia monooxygenase, the 32-kda acetylene-binding polypeptide. one copy of this gene was cloned, and its complete nucleotide sequence is presented. immediately downstream of this gene, in the same operon, is the gene for a 40-kda polypeptide that copurifies with the ammonia monooxygenase acetylene-binding polypeptide. the sequence of the first 692 ...19938468301
oxidation of hydroxylamine by cytochrome p-460 of the obligate methylotroph methylococcus capsulatus bath.an enzyme capable of the oxidation of hydroxylamine to nitrite was isolated from the obligate methylotroph methylococcus capsulatus bath. the absorption spectra in cell extracts, electron paramagnetic resonance spectra, molecular weight, covalent attachment of heme group to polypeptide, and enzymatic activities suggest that the enzyme is similar to cytochrome p-460, a novel iron-containing protein previously observed only in nitrosomonas europaea. the native and subunit molecular masses of the m ...19947928947
the use of a hollow fiber membrane module in sample conditioning prior to electrophoresis.a new method to continuously change the buffer conditions in samples prior to electrophoresis by counter-current dialysis has been developed using a hollow fiber membrane module (variperm m, bitop, witten). it is demonstrated that the collected fractions of a column eluate after hydrophobic interaction chromatography cannot be analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) due to the high content of ammonium sulfate. in contrast, when the hollow fiber membrane m ...19947859717
crystallization and preliminary x-ray analysis of cytochrome c-552 from nitrosomonas europaea.cytochrome c-552 from nitrosomonas europaea was crystallized by the sandwiched drop, vapor diffusion method, with anmmonium sulfate as the precipitant. the crystals were found to belong to the space group p2(1)2(1)2(1), having unit cell dimensions of a = 106.1 a, b = 126.1 a, and c = 57.7 a. the crystals diffracted x-rays at greater than 3.0 a resolution.19947896754
the primary structure of cytochrome p460 of nitrosomonas europaea: presence of a c-heme binding motif.cytochrome p460 and hydroxyamine oxidoreductase of nitrosomonas europaea both catalyze the oxidation of hydroxylamine and contain a 460 nm-absorbing chromophore. the gene (cyp) encoding cytochrome p460 was cloned and sequenced. the predicted amino acid sequence contains a single c-heme binding motif (cxxch) near the carboxy-terminus. cytochrome p460 shows little sequence homology to other c-cytochromes including hydroxyamine oxidoreductase. the presence of a signal peptide and a possible c-heme ...19947957885
evolutionary relationships among ammonia- and nitrite-oxidizing bacteria.comparative 16s rrna sequencing was used to evaluate phylogenetic relationships among selected strains of ammonia- and nitrite-oxidizing bacteria. all characterized strains were shown to be affiliated with the proteobacteria. the study extended recent 16s rrna-based studies of phylogenetic diversity among nitrifiers by the comparison of eight strains of the genus nitrobacter and representatives of the genera nitrospira and nitrospina. the later genera were shown to be affiliated with the delta s ...19947961414
sequence of hcy, a gene encoding cytochrome c-554 from nitrosomonas europaea.cytochrome c-554 (cyt c-554) was purified from nitrosomonas europaea. the n-terminal and internal amino acid sequences were determined. a synthetic oligodeoxyribonucleotide primer based on the n-terminal sequence was used to construct a pcr clone. this clone was used to identify genomic dna fragments containing the gene encoding cyt c-554. we determined the nucleotide sequence of this gene and named it hcy for hydroxylamine oxidoreductase-linked cytochrome.19948063110
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