Hydroxylamine nucleotides

This enzyme [EC 2.7.1.40] catalyzes the reaction of ADP with phosphoenolypyruvate to produce ATP and pyruvate. Other nucleotides that can be used as substrates include UDP, GDP, CDP, IDP, and dADP. The enzyme will also phosphorylate hydroxylamine and fluoride in the presence of carbon dioxide. See Nucleoside 5 -Tri-phosphate Regeneration... 

Nitration opens up another pathway to metabolic activation. Nitro-PAHs are wide-spread environmental pollutants that are mutagenic and carcinogenic. Metabolism of nitro-PAHs could occur via nitro-activation (reduction to hydroxylamine, eventually leading to nitrenes that can bind to nucleotides) and/or by ring oxidation and formation of DEs. ... 

CCM (F1) is based upon a similar principle but uses hydroxylamine and osmium tetroxide to distinguish between mismatched C or T nucleotides, respectively. The position of the mismatch (e.g., the mutation) is defined by sizing on gel electrophoresis after a chemical-mediated cleavage at the reactive position by piperidine. 

Direct experimental evidence for the existence of an ordered conformation of sugar nucleotides in solutions has been reported by Hirano,344 who observed characteristic optical-rotatory changes for a series of these compounds upon transition from water to concentrated urea solutions. The structural requirements for such an ordered conformation are still not clear. However, data at this point, based on indirect kinetic evidence from hydrogenation and hydroxylamin-olysis reactions (see Section IV, p. 360), seem to accord with the hypothetical model just described. Further studies on the conformations of sugar nucleotides in solution are highly desirable. 

Yagil, G., and Anbar, M. (1964). The formation of peroxynitrite by oxidation of chloramine, hydroxylamine and nitrohydroxamate. J. Inorg. Nucleotide Chem. 26, 453-460. 

The first scientific articles from the IKhPS were submitted for publication in the early 1960s, among them being Nikolay s reports on his work in the new field. His major project in nucleotide chemistry was specific chemical modifications of heterocyclic bases. Reactions of hydroxylamine with cytidine and uridine were studied in detail and a new reagent, O-methylhydroxylamine, was proposed for modification of cytidine. These investigations aimed at the development of efficient methods for sequencing and analysis of the secondary structure of polynucleotides. Later, a reaction of chloroacetaldehyde with adenosine and cytidine was discovered and used for preparation of fluorescent polynucleotide derivatives. 

Hydroxylamine acts as a reducing agent when absorbed systemically, producing methemoglobin and the formulation of Heinz bodies in the blood. It can induce hemolytic anemia. It inhibits platelet aggregation and is a nitric oxide vasodilator. Oxy-Imines such as hydroxylamine and methoxylamine disturb DNA replication and act as potent mutagens, causing nucleotide transition from one purine to another or one pyrimidine to another. 

Katsuki, S., Arnold, W., Mittal, C. K., and Murad, F. (1977a). Stimulation of guanylate cyclase by sodium nitroprusside, nitroglycerin and nitric oxide in various tissue preparations and comparison to the effects of sodium azide and hydroxylamine. /. Cyclic Nucleotide Res. 3, 23-35. 

Fig. 2. Fractionation of rat liver proteins modified by ADP-ribosylation at arginine. The add-insoluble fraction from rat liver was dissolved in a buffer containing 6 Mguanidinium chloride, adjusted to pH 7.0, and incubated at 37°C for 4 h. An aliquot was then subjected to column centrifugation to eliminate noncovalently bound nucleotides. Aliquots of the protein fraction were fractionated by size exclusion HPLC using two columns in series (Bio-Sil TSK 250 plus TSK 400, 300 mm X 7.5 mm i.d., each) preceded by a guard column (Bio-Sil TSK 125,75 mm X 7.5 mm i.d.). Fractions of 1 ml each were collected and either analyzed for protein or incubated with neutral hydroxylamine (1M, 37°C, 12 h) and analyzed for ADP-ribose [3)...

Various attempts to demonstrate the accumulation of an intermediate in the conversion of glutamylcysteine to GSH have failed. For example, if, after incubation of ATP with either glutamylcysteine or glycine, the ATP is destroyed with nucleotide pyrophosphatase, GSH synthesis no longer occurs. Moreover, there is no evidence for the accumulation of an activated glutamylcysteine since the incubation mixture of the dipeptide and ATP after deproteinization will no longer react with hydroxylamine. 

Fig. 45. Hypothetical arrangement of serine (or serine-containing peptide) in main polynucleotide chain of desoxyribonucleic acid (Bendich and Rosenkranz, 1962), On the segment of the structure an ester bond between an amino acid and the 3 -carbon atom of a nucleotide is illustrated. It is assumed that rupture of the chain by the action of hydroxylamine takes place at the site of this ester bond as a result a hydroxamate is formed.

The enzymatic reduction of the nitro group involves the stepwise addition of six reducing equivalents potentially derived from reduced pyridine nucleotides (Fig. 8). The first reaction yields a nitroso derivative which is subsequently reduced to a hydroxylamine the hydroxylamino compound is then reduced to the amine. In most systems studied to date (Cemiglia and Somerville, this volume) a single nitroreductase enzyme is responsible for all three reactions and there is little or no accumulation of the intermediates. However, reduction of nitro compounds does not seem to be the physiological function of the enzymes that have been reported to carry out these reactions. Diaphorases (23), ferredoxin-NADPH reductase (33), and a variety of other enzymes from procaryotes and eucaryotes have been shown to catalyze the fortuitous reduction of aromatic nitro groups. 

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