Hydroxylamines: Organic compounds that contain the (-NH2OH) radical.Hydroxylamine: A colorless inorganic compound (HONH2) used in organic synthesis and as a reducing agent, due to its ability to donate nitric oxide.Nitrosomonas: A genus of gram-negative, ellipsoidal or rod-shaped bacteria whose major source of energy and reducing power is from the oxidation of ammonia to nitrite. Its species occur in soils, oceans, lakes, rivers, and sewage disposal systems.Diethyl Pyrocarbonate: Preservative for wines, soft drinks, and fruit juices and a gentle esterifying agent.Nitrosomonas europaea: The type species of the genus NITROSOMONAS, a gram-negative chemolithotroph that oxidizes ammonia to nitrite. It is found in soil, sewage, freshwater, and on building walls, and especially in polluted areas where air contains high levels of nitrogen compounds.Sulfamethoxazole: A bacteriostatic antibacterial agent that interferes with folic acid synthesis in susceptible bacteria. Its broad spectrum of activity has been limited by the development of resistance. (From Martindale, The Extra Pharmacopoeia, 30th ed, p208)Nitrites: Salts of nitrous acid or compounds containing the group NO2-. The inorganic nitrites of the type MNO2 (where M=metal) are all insoluble, except the alkali nitrites. The organic nitrites may be isomeric, but not identical with the corresponding nitro compounds. (Grant & Hackh's Chemical Dictionary, 5th ed)HydrazinesTriacetoneamine-N-Oxyl: Cyclic N-oxide radical functioning as a spin label and radiation-sensitizing agent.Oxidoreductases: The class of all enzymes catalyzing oxidoreduction reactions. The substrate that is oxidized is regarded as a hydrogen donor. The systematic name is based on donor:acceptor oxidoreductase. The recommended name will be dehydrogenase, wherever this is possible; as an alternative, reductase can be used. Oxidase is only used in cases where O2 is the acceptor. (Enzyme Nomenclature, 1992, p9)Acylation: The addition of an organic acid radical into a molecule.Dapsone: A sulfone active against a wide range of bacteria but mainly employed for its actions against MYCOBACTERIUM LEPRAE. Its mechanism of action is probably similar to that of the SULFONAMIDES which involves inhibition of folic acid synthesis in susceptible organisms. It is also used with PYRIMETHAMINE in the treatment of malaria. (From Martindale, The Extra Pharmacopoeia, 30th ed, p157-8)Kinetics: The rate dynamics in chemical or physical systems.Palmitic Acids: A group of 16-carbon fatty acids that contain no double bonds.Oxidation-Reduction: A chemical reaction in which an electron is transferred from one molecule to another. The electron-donating molecule is the reducing agent or reductant; the electron-accepting molecule is the oxidizing agent or oxidant. Reducing and oxidizing agents function as conjugate reductant-oxidant pairs or redox pairs (Lehninger, Principles of Biochemistry, 1982, p471).Oximes: Compounds that contain the radical R2C=N.OH derived from condensation of ALDEHYDES or KETONES with HYDROXYLAMINE. Members of this group are CHOLINESTERASE REACTIVATORS.Nitrogen Oxides: Inorganic oxides that contain nitrogen.Palmitic Acid: A common saturated fatty acid found in fats and waxes including olive oil, palm oil, and body lipids.Ammonia: A colorless alkaline gas. It is formed in the body during decomposition of organic materials during a large number of metabolically important reactions. Note that the aqueous form of ammonia is referred to as AMMONIUM HYDROXIDE.Nitrite Reductases: A group of enzymes that oxidize diverse nitrogenous substances to yield nitrite. (Enzyme Nomenclature, 1992) EC 1.Nitrite Reductase (NAD(P)H): An enzyme found primarily in BACTERIA and FUNGI that catalyzes the oxidation of ammonium hydroxide to nitrite. It is an iron-sulfur HEME; FLAVOPROTEIN containing siroheme and can utilize both NAD and NADP as cofactors. This enzyme was formerly classified as EC 22.214.171.124.Cyclic N-Oxides: Heterocyclic compounds in which an oxygen is attached to a cyclic nitrogen.Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.Hydrogen-Ion Concentration: The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)Cytochrome-B(5) Reductase: A FLAVOPROTEIN oxidoreductase that occurs both as a soluble enzyme and a membrane-bound enzyme due to ALTERNATIVE SPLICING of a single mRNA. The soluble form is present mainly in ERYTHROCYTES and is involved in the reduction of METHEMOGLOBIN. The membrane-bound form of the enzyme is found primarily in the ENDOPLASMIC RETICULUM and outer mitochondrial membrane, where it participates in the desaturation of FATTY ACIDS; CHOLESTEROL biosynthesis and drug metabolism. A deficiency in the enzyme can result in METHEMOGLOBINEMIA.Osmium Tetroxide: (T-4)-Osmium oxide (OsO4). A highly toxic and volatile oxide of osmium used in industry as an oxidizing agent. It is also used as a histological fixative and stain and as a synovectomy agent in arthritic joints. Its vapor can cause eye, skin, and lung damage.Sulfites: Inorganic salts of sulfurous acid.Ferredoxin-Nitrite Reductase: An IRON-containing protein that uses siroheme and 4Fe-4S iron-sulfur centers as prosthetic groups. It catalyzes the six-electron oxidation of AMMONIA to nitrite.Histidine: An essential amino acid that is required for the production of HISTAMINE.Halorhodopsins: Light driven chloride ion pumps that are ubiquitously found in halophilic archaea (HALOBACTERIALES).Dithionite: Dithionite. The dithionous acid ion and its salts.Cytochromes a1: A subclass of heme a containing cytochromes have a reduced alpha-band absorption of 587-592 nm. They are primarily found in microorganisms.Iodates: Inorganic salts of iodic acid (HIO3).Formates: Derivatives of formic acids. Included under this heading are a broad variety of acid forms, salts, esters, and amides that are formed with a single carbon carboxy group.Myristic Acids: 14-carbon saturated monocarboxylic acids.Amino Acid Sequence: The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.Nitroso CompoundsMethemoglobinButanesBorohydrides: A class of inorganic or organic compounds that contain the borohydride (BH4-) anion.Enzyme Reactivators: Compounds which restore enzymatic activity by removing an inhibitory group bound to the reactive site of the enzyme.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Heme: The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.Chromatography, High Pressure Liquid: Liquid chromatographic techniques which feature high inlet pressures, high sensitivity, and high speed.Beggiatoa: A genus of colorless, filamentous bacteria in the family THIOTRICHACEAE whose cells contain inclusions of sulfur granules. When found in decaying seaweed beds and polluted water, its presence signals environmental degradation.Bromates: Negative ions or salts derived from bromic acid, HBrO3.Hemeproteins: Proteins that contain an iron-porphyrin, or heme, prosthetic group resembling that of hemoglobin. (From Lehninger, Principles of Biochemistry, 1982, p480)Spectrophotometry, Ultraviolet: Determination of the spectra of ultraviolet absorption by specific molecules in gases or liquids, for example Cl2, SO2, NO2, CS2, ozone, mercury vapor, and various unsaturated compounds. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Pentanones: 5-carbon straight-chain or branched-chain ketones.Sensory Rhodopsins: Photosensory rhodopsins found in microorganisms such as HALOBACTERIA. They convert light signals into biochemical information that regulates certain cellular functions such as flagellar motor activity.Pralidoxime Compounds: Various salts of a quaternary ammonium oxime that reconstitute inactivated acetylcholinesterase, especially at the neuromuscular junction, and may cause neuromuscular blockade. They are used as antidotes to organophosphorus poisoning as chlorides, iodides, methanesulfonates (mesylates), or other salts.Rhodopsin: A purplish-red, light-sensitive pigment found in RETINAL ROD CELLS of most vertebrates. It is a complex consisting of a molecule of ROD OPSIN and a molecule of 11-cis retinal (RETINALDEHYDE). Rhodopsin exhibits peak absorption wavelength at about 500 nm.Chemistry: A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.Quaternary Ammonium Compounds: Derivatives of ammonium compounds, NH4+ Y-, in which all four of the hydrogens bonded to nitrogen have been replaced with hydrocarbyl groups. These are distinguished from IMINES which are RN=CR2.Iodobenzoates: Benzoic acid esters or salts substituted with one or more iodine atoms.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Chemical Phenomena: The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.Molecular Weight: The sum of the weight of all the atoms in a molecule.PhenanthrolinesCytochromes c1: The 30-kDa membrane-bound c-type cytochrome protein of mitochondria that functions as an electron donor to CYTOCHROME C GROUP in the mitochondrial and bacterial RESPIRATORY CHAIN. (From Enzyme Nomenclature, 1992, p545)Escherichia coli: A species of gram-negative, facultatively anaerobic, rod-shaped bacteria (GRAM-NEGATIVE FACULTATIVELY ANAEROBIC RODS) commonly found in the lower part of the intestine of warm-blooded animals. It is usually nonpathogenic, but some strains are known to produce DIARRHEA and pyogenic infections. Pathogenic strains (virotypes) are classified by their specific pathogenic mechanisms such as toxins (ENTEROTOXIGENIC ESCHERICHIA COLI), etc.