Presence Of Ammonium Ions Research Articles

Formation of cyanide ion or cyanogen chloride through the cleavage of aromatic rings by nitrous acid or chlorine. XI: On the reaction of purine bases with hypochlorous acid in the presence of ammonium ion

Cyanogen chloride was formed by the reactions of purine bases(adenine and guanine) with hypochlorous acid in the presence of ammonium ion. The origin of the carbon and nitrogen atoms of cyanogen chloride formed from adenine was investigated by use of synthetic adenines variously labeled with the isotope of nitrogen( 15N) or carbon( 13C).

Formation of Cyanogen Chloride by the Reactions of Amino Acids, Peptides and Proteins with Chlorine in the Presence of Ammonium Ion (Proceedings of the 14th Symposium on Environmental Pollutants and Toxicology)

Formation of Cyanogen Chloride by the Reactions of Amino Acids, Peptides and Proteins with Chlorine in the Presence of Ammonium Ion (Proceedings of the 14th Symposium on Environmental Pollutants and Toxicology)

Choline transport in Pseudomonas aeruginosa

Choline used as the sole carbon or carbon and nitrogen source induces in Pseudomonas aeruginosa an active transport system. The induction of the choline uptake is repressed by succinate independently of the presence of ammonium ion in the culture medium. The repression mediated by succinate was insensitive to cyclic AMP. Substitution for dibutyryl-cyclic AMP was without effect. Choline metabolites that also support the growth of Pseudomonas aeruginosa were poor inducer agents of the choline transport. Kinetic evidence and the employment of choline metabolites as effectors indicated that the choline uptake system of this bacterium is formed by at least two components: one of high affinity (Km = 3 microM) and another of low affinity (Km = 400 microM). Contrary to what occurs in the synaptosome system, the high affinity form for the choline uptake was not dependent on Na+ ions and is not inhibited by hemicholinium-3. Since Pseudomonas aeruginosa can utilize choline as the sole carbon and nitrogen source, the induction of the choline transport with two components in this bacterium may be related to its own strategy to survive and grow in an adverse environment.

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.

The loss of halide and sulphate ions from melting ice

Artificial ices of known composition were melted under laboratory conditions to monitor shifts in the relative ionic composition of meltwaters. Chloride, bromide and iodide tend to be lost from the melting ice more readily than fluoride, which is incorporated in the ice grain interior. The presence of ammonium ions further inhibits fluoride loss. Hydrogen ions cause fluoride to be lost as readily as the other halides. Sulphate is lost more rapidly than chloride at environmental concentrations (<100 μmol l −1), but at higher concentrations (∼ 0.01 mol l −1) chloride can be lost just as readily as sulphate. The composition of meltwater may be described in terms of the mixing of two types of solutions: (1) intergranular surficial brines with a high solute concentration, which occupy the ice grain boundaries and (2) relatively dilute meltwater derived from the ice grain interiors. Deviations from simple two component behaviour suggest slightly different distributions for the chloride and the sulphate ions in the interfacial region between the brine and the intragranular ice. The melting of such systems has been examined using a simple mathematical model.

Formation of cyanogen chloride by the reaction of amino acids with hypochlorous acid in the presence of ammonium ion

Aliphatic amino acids reacted with hypochlorous acid and ammonium ion, i.e. chloramine, to give cyanogen chloride. The yields of cyanogen chloride were, for example, 3 – 4 % from valine, leucine and isoleucine, 11.2 % from serine and 13.7 % from threonine. The nitrogen atom of cyanogen chloride formed from leucine was proved to originate not from chloramine, but from leucine.

Steady-state kinetic analysis for the reaction of ammonium and alkylammonium ions with methylamine dehydrogenase from bacterium W3A1.

The steady-state kinetic mechanism for the reaction of n-alkylamines and phenazine ethosulfate (PES) or phenazine methosulfate (PMS) with methylamine dehydrogenase from bacterium W3A1 is found to be of the ping-pong type. This conclusion is based on the observations that 1/v versus 1/[methylamine] or 1/[butylamine] plots, at various constant concentrations of an oxidizing substrate, and 1/v versus 1/[PES] or 1/[PMS] plots, at various constant concentrations of a reducing substrate, are parallel. Additionally, the values of kcat/Km for four n-alkylamines are identical when PES is the oxidizing substrate, as were the kcat/Km values for four reoxidizing substrates when methylamine was the reducing substrate. Last, analysis of steady-state kinetic data obtained when methylamine and propylamine are presented to the enzyme simultaneously and PES and PMS are used simultaneously also supports the involvement of a ping-pong mechanism. The enzymic reaction with either methylamine or PES is dependent on the ionic strength, and the data indicate that each interacts with an anionic site on methylamine dehydrogenase. The presence of ammonium ion at low concentration activates the enzyme, but at high concentration this ion is a competitive inhibitor in the reaction involving methylamine and the enzyme. A complete steady-state mechanism describing these ammonia effects is presented and is discussed in light of the nature of the pyrroloquinoline quinone cofactor covalently bound to the enzyme.

Influence of heme-surrounding amino acid residues on the manganese (V)-nitrido bond in manganese-substituted hemoproteins: resonance Raman evidence for porphyrin core expansion and reduction of the manganese(V)-nitrido stretching force constant.

Nitridomanganese(V) protoporphyrin IX was prepared by hypochlorite oxidation of the corresponding manganese(III) protoporphyrin IX derivative in the presence of ammonium ion and by photolysis of the corresponding azidomanganese(III) complex. Myoglobin and horseradish peroxidase containing this novel protoporphyrin derivative were prepared for the first time. These remarkably stable species were examined by electronic absorption, electron paramagnetic resonance, and resonance Raman spectroscopies. The MnV-N stretching modes of the nitridomanganese(V)-substituted myoglobin and horseradish peroxidase were observed at 1010 and 1003 cm-1, respectively, by resonance Raman spectroscopy, while the MnV-N stretching frequency for nitridomanganese(V) protoporphyrin IX in 0.1 N aqueous NaOH was found at 1046 cm-1. The equilibrium dissociation energies of MnV-N bonds in these complexes were estimated from vibrational overtone spacings by introducing the Morse potential energy function, were found to be around 4.5 eV, and seemed independent of the surroundings of the manganese porphyrin, although its force constant decreased from 7.3 to 6.7 mdyn/A upon incorporation into apoprotein. The porphyrin ring modes of these nitridomanganese(V) derivatives were influenced greatly upon incorporation into apoproteins, suggestive of the occurrence of porphyrin core expansion. Upon this core expansion the MnV center moves into the mean plane of porphyrin plane, but the access of nitrido (N) toward MnV is restricted due to a steric hindrance from porphyrin pyrrole nitrogens. The resulting stretched MnV-N bond might cause lowering of the MnV-N stretching frequency upon incorporation into apoprotein.

Isolation of the NPR1 gene responsible for the reactivation of ammonia-sensitive amino-acid permeases in Saccharomyces cerevisiae. RNA analysis and gene dosage effects.

The NPR1 gene codes for a protein, called the nitrogen permease reactivator protein or Npr1, which appears to promote the activity of several permeases for nitrogenous substances under conditions of nitrogen catabolite derepression, but fails to do so in the presence of ammonium ions. This gene has been cloned. Its transcription seems unaffected by growth on ammonia, so any ammonia regulation of Npr1 function most likely occurs at another level. In order to elucidate further the mechanism of permease inactivation, which requires an intact NPI1 gene product (NPI1 for nitrogen permease inactivator gene, formerly termed MUT2) and the role of Npr1 in counteracting this process, we have studied the effects of NPR1 and NPI1 gene dosage on general amino-acid permease activity. On nitrogen-derepressing media, NPR1 gene dose can be increased from 1 copy in a diploid to 16 plasmid-borne copies in a haploid strain without altering general amino-acid permease activity. On minimal ammonia medium, the plasmid-bearing haploid cells exhibit low but increased general amino-acid permease activity with respect to non-transformed cells. The adverse effect of the NPI1 gene product on general amino-acid permease activity is reduced when NPI1 gene dose is decreased to 1 gene copy in a diploid strain, regardless of the nitrogen source. We hypothesize that this product inactivates the permease by stoichiometric binding and that the Npr1 protein or a product of its catalytic action opposes this binding under conditions of nitrogen derepression.

Formation of Cyanogen Chloride by the Reaction of Amino Acids with Chlorine in the Presence of Ammonium Ion

Formation of Cyanogen Chloride by the Reaction of Amino Acids with Chlorine in the Presence of Ammonium Ion

Formation of cyanide ion or cyanogen chloride through the cleavage of aromatic rings by nitrous acid or chlorine. IX. On the reactions of chlorinated, nitrated, carboxylated or methylated benzene derivatives with hypochlorous acid in the presence of ammonium ion

Chlorinated, nitrated, carboxylated or methylated benzenes, phenols and anilines reacted with chloramine to give cyanogen chloride, independently of the positions and the numbers of the substituents. Among these compounds, 2,4,6-trichlorophenol afforded cyanogen chloride in a relatively high yield of 13.3%, and the intermediates in the reaction were 2,6-dichloro-1,4-benzoquinone-4-(N-chloro)imine and 4,6-dichloro-1,2-benzoquinone-2-(N-chloro)-imine, of which the latter was the main intermediate.

Hot atom chemistry in oxyanion targets. Part IV1: Recoil isochronal annealing in permanganates

Investigations on isochronal annealing behaviour of /n, γ/ activated56Mn recoils in crystalline potassium and ammonium permanganates have given different results indicating a varying degree of sensitivity of the samples to recoil annealing. The presence of ammonium ion in ammonium permanganate shows the reduction of recoil species during annealing. Vand-Primak model has been utilized to deduce the kinetic behaviour by which the energy of activation is found to be 1.1 and 1.2 eV for KMnO4 and NH4MnO4, respectively. Furthermore, the present work reveals the role of defects in the transient reactions of the lattice stable precursors and hence the mechanism of the recoil reactions.

Gaseous ammonia and ammonium ions in the free troposphere

Ammonia, the most important alkaline compound commonly found in the atmosphere, has a key role in aerosol chemistry. Gaseous ammonia is released at the Earth's surface primarily through the decomposition of organic material and, due to its extremely large solubility in water and reactivity with acid aerosol components, is efficiently removed by interaction with aqueous and acid aerosols. While the presence of ammonium ions (NH4+) in aerosols and rain water is well established, there have been few studies of gaseous ammonia and its abundance is not well established, particularly in the free troposphere1. This is probably due to the difficulty in developing sufficiently sensitive analytical methods, which are not affected by interference of ammonium-containing aerosols. Due to its large proton affinity or gas-phase basicity, ammonia vapour is expected to react also with atmospheric gaseous positive ions leading to gaseous NH4+ ‘core ions’. Detection of the gaseous NH4+ core ions, which have not yet been observed in the free atmosphere, may provide sensitive means of detecting atmospheric ammonia vapour2,3,4. We report here on the first measurements of this ion in the free atmosphere at altitudes from 4,000 to 8,000 m. Ammonia vapour abundances inferred from these data are very low suggesting efficient heterogeneous ammonia removal and very low ammonia saturation pressures over aerosols.

An X-Ray Photoelectron Spectroscopic Study of Some Ammonium Uranates

X-ray photoelectron and infrared spectroscopy have been used to investigate the chemical composition of some ammonium uranates, all of which were prepared by the direct titration of uranyl nitrate solution with ammonia. Some correlation is found between the U(4f) binding energy and the pH of the solution used to prepare the uranates, and the v3 asymmetric stretching frequency for the uranyl (UO22+) ion. All samples showed the presence of ammonium ions and possibly two types of hydroxide species. Strong retention of nitrate ions was also observed for all samples.

Effect of Growth Conditions on Halomethane Production by Phellinus Species: Biological and Environmental Implications

Production of the gaseous secondary metabolite chloromethane (CH,Cl) by the fungus Phellinus pomaceus has been measured on a variety of media using headspace techniques. On glucosebased media, CH3C1 production was linearly related to the logarithm of chloride ion concentration. At concentrations less than 4 mM, over 90% of the chloride ion in the medium was converted to CH3C1. Bromide and iodide, but not fluoride, were substrates for the methylating system. The pH range 5 to 7 was optimal for CH3C1 biosynthesis and the presence of ammonium ions stimulated the process. Supplementation of the medium with methionine, serine or folic acid did not affect overall CH3CI production. With cellulosic media, CH3C1 yields based on chloride ion present in the medium were high, ranging from 75% at 0.4 mM to 90% at 50m~. Bromomethane yields from bromide averaged 70% between 0.5 and 25 mM. Iodomethane yields of approximately 60% were obtained with up to 1 mM-iodide but declined sharply above this concentration. When equimolar concentrations of the three halide ions were present, the different halides were methylated sequentially, iodide being the most preferred substrate and chloride the least. Gas chromatography/mass spectrometry of other headspace volatiles from P. pomaceus mycelia revealed, amongst the main components, methyl esters of 2-furoic, benzoic and salicylic acids. The pseudohalide ion thiocyanate acted as a specific inhibitor of not only halomethane biosynthesis but also methyl benzoate formation, suggesting that methylation of halide and benzoate may be mediated by the same biochemical system. Of five other species of Phellinus previously reported to produce CH,Cl, only P. ribis and P. occidentalis exhibited high efficiency conversion of chloride ion to CH3Cl. P. robiniae converted only a small proportion of available chloride to CH3Cl, whilst no CH3Cl production by P. conchatus or P. vinosus could be demonstrated on any of the media employed. The biochemical, ecological and environmental significance of fungal halomethane biosynthesis is discussed.

Atrial muscarinic receptors: effect of Triton X-100 on guanine nucleotide and ammonium ion modulation.

Membranes isolated from bovine atria were labeled with [3H]quinuclidinyl benzylate (3H-QNB), in control conditions and after 0.02% Triton X-100. This treatment inactivated about 20% of muscarinic receptor sites without loss of protein. The remaining 80% sites showed no changes in affinity, as determined by equilibrium or kinetic binding. Competition experiments with carbachol showed no differences in IC50 and Hill number between the control and detergent-membranes, suggesting that the different populations of agonist binding sites are inactivated in equal proportions by the detergent. In binding experiments, done in the presence of carbachol and guanine nucleotides, the detergent treated membranes were slightly more sensitive to the enhancing action of the nucleotide. The inhibition caused by ammonium ions was also more marked in the Triton X-100 treated membranes. The decay of binding with thermal inactivation was faster in the detergent treated membranes and this effect was enhanced in the presence of ammonium ions. These results may be interpreted as an indication that the receptors, remaining after the mild Triton X-100 treatment, are equally sensitive to the inactivation. We suggest that, while maintaining the heterogeneity of sites, the detergent produces a perturbation that could affect the molecular interactions between the receptor and other components of the membrane.

Inactivation of Serine:Glyoxylate and Glutamate:Glyoxylate Aminotransferases from Tobacco Leaves by Glyoxylate in the Presence of Ammonium Ion

Serine:glyoxylate and glutamate:glyoxylate aminotransferases (SGAT and GGAT), which catalyze the formation of glycine from glyoxylate during photorespiration, have been purified >300-fold from tobacco leaf extracts. Incubation with glyoxylate in the absence of amino acid substrate resulted in the time- and concentration-dependent inhibition of the partially purified enzymes. The second order rate constants for glyoxylate inhibition were 1.25 and 0.175 per millimolar per minute for SGAT and GGAT, respectively. The enzymes of highest specific activity were not inhibited by 5 millimolar glyoxylate alone but when 1 millimolar NH(4) (+) was added to 1 millimolar glyoxylate for 10 min in the absence of amino donor, SGAT was irreversibly inhibited more than 50%. GGAT was inhibited 50% in 10 minutes by 15 millimolar NH(4) (+) and 1 millimolar glyoxylate. By itself, NH(4) (+) was a reversible inhibitor; SGAT and GGAT were inhibited 50% at 6 millimolar and 50 millimolar, respectively. The irreversible inhibition occurred only with glyoxylate and NH(4) (+) added together; oxalate, formate, acetaldehyde, pyruvate, hydroxypyruvate, and alpha-ketoglutarate did not inhibit either in the presence or absence of NH(4) (+). Glyoxylate and NH(4) (+) could form a carbinolamine which is a serine analog and might bind irreversibly to the enzymes. Under conditions in vivo in which reassimilation of NH(4) (+) is reduced or blocked, the activity of SGAT may be inhibited and if glyoxylate is available, as in leaf peroxisomes, irreversible inhibition may occur.

Kryptanden mit Galactose‐Bausteinen

Cryptands with Structural Units of GalactoseTetrahydroxybis(galactopyrano)‐[18]crown‐6 2 does not reveal under basic conditions in the presence of oligoethylene glycol ditosylates any trans‐annular etherification involving positions 6/6′ or 4/4′, respectively, instead the systems 4a and b with three macrocycles are generated. After protection of the 6/6′‐hydroxy groups a trans‐annular reaction is possible. Thus, the chiral cryptands 6a and b are accessible. Complexing properties in the presence of ammonium ions have been studied for 6a.

Formation of cyanide ion or cyanogen chloride through the cleavage of aromatic rings by nitrous acid or chlorine. VIII. On the reaction of humic acid with hypochlorous acid in the presence of ammonium ion

Cyanogen chloride was formed by the reaction of humic acid with hypochlorous acid in the presence of ammonium ion. Furthermore, cyanogen chloride was also formed when ammonium ion and hypochlorous acid were added to raw water sampled at water treatment plants.

Acceleration of the rate of fermentation by Saccharomyces cerevisiae in the presence of ammonium ion

The rate of fermentation of both d-glucose and maltose in a defined medium by a brewing strain of Saccharomyces cerevisiae was found to be dependent on the availability of NH 4 +. The glycolytic rate did not correlate with intracellular NH 4 + and activation by NH 4 + was blocked by cycloheximide. The ability of several amino acids to activate glycolysis followed the same order as their effectiveness as sole sources of nitrogen. It therefore seems that NH 4 + does not stimulate fermentation through direct activation of glycolytic enzymes, but through its function as a substrate for protein synthesis.