Sulfite Oxidase: A MOLYBDENUM requiring enzyme that catalyzes the terminal reaction in the oxidative degradation of SULFUR AMINO ACIDS with the formation of a sulfate. A deficiency of sulfite oxidase results in sulfocysteinuria.Oxidoreductases Acting on Sulfur Group Donors: Oxidoreductases with specificity for oxidation or reduction of SULFUR COMPOUNDS.Sulfites: Inorganic salts of sulfurous acid.Molybdenum: A metallic element with the atomic symbol Mo, atomic number 42, and atomic weight 95.94. It is an essential trace element, being a component of the enzymes xanthine oxidase, aldehyde oxidase, and nitrate reductase. (From Dorland, 27th ed)Sulfite Dehydrogenase: An enzyme that catalyzes oxidation of sulfite to sulfate along with the reduction of FERROCYTOCHROME C to FERRICYTOCHROME C.Pteridines: Compounds based on pyrazino[2,3-d]pyrimidine which is a pyrimidine fused to a pyrazine, containing four NITROGEN atoms.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)Coenzymes: Small molecules that are required for the catalytic function of ENZYMES. Many VITAMINS are coenzymes.NADPH Oxidase: A flavoprotein enzyme that catalyzes the univalent reduction of OXYGEN using NADPH as an electron donor to create SUPEROXIDE ANION. The enzyme is dependent on a variety of CYTOCHROMES. Defects in the production of superoxide ions by enzymes such as NADPH oxidase result in GRANULOMATOUS DISEASE, CHRONIC.Metalloproteins: Proteins that have one or more tightly bound metal ions forming part of their structure. (Dorland, 28th ed)Tungsten: Tungsten. A metallic element with the atomic symbol W, atomic number 74, and atomic weight 183.85. It is used in many manufacturing applications, including increasing the hardness, toughness, and tensile strength of steel; manufacture of filaments for incandescent light bulbs; and in contact points for automotive and electrical apparatus.Brain Diseases, Metabolic, Inborn: Brain disorders resulting from inborn metabolic errors, primarily from enzymatic defects which lead to substrate accumulation, product reduction, or increase in toxic metabolites through alternate pathways. The majority of these conditions are familial, however spontaneous mutation may also occur in utero.Xanthine Oxidase: An iron-molybdenum flavoprotein containing FLAVIN-ADENINE DINUCLEOTIDE that oxidizes hypoxanthine, some other purines and pterins, and aldehydes. Deficiency of the enzyme, an autosomal recessive trait, causes xanthinuria.Acid Rain: Acidic water usually pH 2.5 to 4.5, which poisons the ecosystem and adversely affects plants, fishes, and mammals. It is caused by industrial pollutants, mainly sulfur oxides and nitrogen oxides, emitted into the atmosphere and returning to earth in the form of acidic rain water.Thiobacillus: A genus of gram-negative, rod-shaped bacteria that derives energy from the oxidation of one or more reduced sulfur compounds. Many former species have been reclassified to other classes of PROTEOBACTERIA.Sulfite Reductase (Ferredoxin): A FERREDOXIN-dependent oxidoreductase that is primarily found in PLANTS where it plays an important role in the assimilation of SULFUR atoms for the production of CYSTEINE and METHIONINE.Metal Metabolism, Inborn ErrorsXanthine Dehydrogenase: An enzyme that catalyzes the oxidation of XANTHINE in the presence of NAD+ to form URIC ACID and NADH. It acts also on a variety of other purines and aldehydes.Sulfite Reductase (NADPH): A NADPH-dependent oxidase that reduces hydrogen sulfite to HYDROGEN SULFIDE. It is found in many microoganisms.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).Sulfur: An element that is a member of the chalcogen family. It has an atomic symbol S, atomic number 16, and atomic weight [32.059; 32.076]. It is found in the amino acids cysteine and methionine.Chickens: Common name for the species Gallus gallus, the domestic fowl, in the family Phasianidae, order GALLIFORMES. It is descended from the red jungle fowl of SOUTHEAST ASIA.Heme: The color-furnishing portion of hemoglobin. It is found free in tissues and as the prosthetic group in many hemeproteins.Monoamine Oxidase: An enzyme that catalyzes the oxidative deamination of naturally occurring monoamines. It is a flavin-containing enzyme that is localized in mitochondrial membranes, whether in nerve terminals, the liver, or other organs. Monoamine oxidase is important in regulating the metabolic degradation of catecholamines and serotonin in neural or target tissues. Hepatic monoamine oxidase has a crucial defensive role in inactivating circulating monoamines or those, such as tyramine, that originate in the gut and are absorbed into the portal circulation. (From Goodman and Gilman's, The Pharmacological Basis of Therapeutics, 8th ed, p415) EC 1.4.3.4.Electron Spin Resonance Spectroscopy: A technique applicable to the wide variety of substances which exhibit paramagnetism because of the magnetic moments of unpaired electrons. The spectra are useful for detection and identification, for determination of electron structure, for study of interactions between molecules, and for measurement of nuclear spins and moments. (From McGraw-Hill Encyclopedia of Science and Technology, 7th edition) Electron nuclear double resonance (ENDOR) spectroscopy is a variant of the technique which can give enhanced resolution. Electron spin resonance analysis can now be used in vivo, including imaging applications such as MAGNETIC RESONANCE IMAGING.Hydrogensulfite Reductase: An enzyme found primarily in SULFUR-REDUCING BACTERIA where it plays an important role in the anaerobic carbon oxidation pathway.Protein-Lysine 6-Oxidase: An enzyme oxidizing peptidyl-lysyl-peptide in the presence of water & molecular oxygen to yield peptidyl-allysyl-peptide plus ammonia & hydrogen peroxide. EC 1.4.3.13.CME-CarbodiimideSulfates: Inorganic salts of sulfuric acid.Nitrate Reductase (NADH): An NAD-dependent enzyme that catalyzes the oxidation of nitrite to nitrate. It is a FLAVOPROTEIN that contains IRON and MOLYBDENUM and is involved in the first step of nitrate assimilation in PLANTS; FUNGI; and BACTERIA. It was formerly classified as EC 1.6.6.1.Nitrate Reductase: An enzyme that catalyzes the oxidation of nitrite to nitrate. It is a cytochrome protein that contains IRON and MOLYBDENUM.Hibiscus: A plant genus of the family MALVACEAE. Members contain CITRIC ACID; MALATES; ANTHOCYANINS; FLAVONOIDS; GLYCOSIDES; DIETARY FIBER; and LIGNANS. Hibiscus sabdariffa is common constituent of HERBAL TEAS. Hibiscus cannabinus is a source of hemp fiber for TEXTILES.Spectrophotometry: The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.Deficiency Diseases: A condition produced by dietary or metabolic deficiency. The term includes all diseases caused by an insufficient supply of essential nutrients, i.e., protein (or amino acids), vitamins, and minerals. It also includes an inadequacy of calories. (From Dorland, 27th ed; Stedman, 25th ed)Nitrate Reductases: Oxidoreductases that are specific for the reduction of NITRATES.Thiosulfates: Inorganic salts of thiosulfuric acid possessing the general formula R2S2O3.Aldehyde Oxidase: An aldehyde oxidoreductase expressed predominantly in the LIVER; LUNGS; and KIDNEY. It catalyzes the oxidation of a variety of organic aldehydes and N-heterocyclic compounds to CARBOXYLIC ACIDS, and also oxidizes quinoline and pyridine derivatives. The enzyme utilizes molybdenum cofactor and FAD as cofactors.Glucose Oxidase: An enzyme of the oxidoreductase class that catalyzes the conversion of beta-D-glucose and oxygen to D-glucono-1,5-lactone and peroxide. It is a flavoprotein, highly specific for beta-D-glucose. The enzyme is produced by Penicillium notatum and other fungi and has antibacterial activity in the presence of glucose and oxygen. It is used to estimate glucose concentration in blood or urine samples through the formation of colored dyes by the hydrogen peroxide produced in the reaction. (From Enzyme Nomenclature, 1992) EC 1.1.3.4.Sulfur Dioxide: A highly toxic, colorless, nonflammable gas. It is used as a pharmaceutical aid and antioxidant. It is also an environmental air pollutant.Kinetics: The rate dynamics in chemical or physical systems.Pterins: Compounds based on 2-amino-4-hydroxypteridine.Electron Transport: The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)D-Amino-Acid OxidaseAmino Acids, SulfurMitochondria, Liver: Mitochondria in hepatocytes. As in all mitochondria, there are an outer membrane and an inner membrane, together creating two separate mitochondrial compartments: the internal matrix space and a much narrower intermembrane space. In the liver mitochondrion, an estimated 67% of the total mitochondrial proteins is located in the matrix. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p343-4)Liver: A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.Cytochromes: Hemeproteins whose characteristic mode of action involves transfer of reducing equivalents which are associated with a reversible change in oxidation state of the prosthetic group. Formally, this redox change involves a single-electron, reversible equilibrium between the Fe(II) and Fe(III) states of the central iron atom (From Enzyme Nomenclature, 1992, p539). The various cytochrome subclasses are organized by the type of HEME and by the wavelength range of their reduced alpha-absorption bands.Amino Acid Metabolism, Inborn Errors: Disorders affecting amino acid metabolism. The majority of these disorders are inherited and present in the neonatal period with metabolic disturbances (e.g., ACIDOSIS) and neurologic manifestations. They are present at birth, although they may not become symptomatic until later in life.Monoamine Oxidase Inhibitors: A chemically heterogeneous group of drugs that have in common the ability to block oxidative deamination of naturally occurring monoamines. (From Gilman, et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 8th ed, p414)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)Ferricyanides: Inorganic salts of the hypothetical acid, H3Fe(CN)6.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.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)Ascorbate Oxidase: An enzyme that converts ascorbic acid to dehydroascorbic acid. EC 1.10.3.3.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.Galactose Oxidase: An enzyme that oxidizes galactose in the presence of molecular oxygen to D-galacto-hexodialdose. It is a copper protein. EC 1.1.3.9.Catalytic Domain: The region of an enzyme that interacts with its substrate to cause the enzymatic reaction.Catalysis: The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Urate Oxidase: An enzyme that catalyzes the conversion of urate and unidentified products. It is a copper protein. The initial products decompose to form allantoin. EC 1.7.3.3.Oxygen: An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.Acyl-CoA Oxidase: An enzyme that catalyzes the first and rate-determining steps of peroxisomal beta-oxidation of fatty acids. It acts on COENZYME A derivatives of fatty acids with chain lengths from 8 to 18, using FLAVIN-ADENINE DINUCLEOTIDE as a cofactor.