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.
A purine base found in most body tissues and fluids, certain plants, and some urinary calculi. It is an intermediate in the degradation of adenosine monophosphate to uric acid, being formed by oxidation of hypoxanthine. The methylated xanthine compounds caffeine, theobromine, and theophylline and their derivatives are used in medicine for their bronchodilator effects. (Dorland, 28th ed)
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.
Purine bases found in body tissues and fluids and in some plants.
A XANTHINE OXIDASE inhibitor that decreases URIC ACID production. It also acts as an antimetabolite on some simpler organisms.
A xanthine oxidase inhibitor.
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.
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.
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)
A purine and a reaction intermediate in the metabolism of adenosine and in the formation of nucleic acids by the salvage pathway.
Highly reactive compounds produced when oxygen is reduced by a single electron. In biological systems, they may be generated during the normal catalytic function of a number of enzymes and during the oxidation of hemoglobin to METHEMOGLOBIN. In living organisms, SUPEROXIDE DISMUTASE protects the cell from the deleterious effects of superoxides.
Purine bases related to hypoxanthine, an intermediate product of uric acid synthesis and a breakdown product of adenine catabolism.
Highly reactive molecules with an unsatisfied electron valence pair. Free radicals are produced in both normal and pathological processes. They are proven or suspected agents of tissue damage in a wide variety of circumstances including radiation, damage from environment chemicals, and aging. Natural and pharmacological prevention of free radical damage is being actively investigated.
The white liquid secreted by the mammary glands. It contains proteins, sugar, lipids, vitamins, and minerals.
An oxidation product, via XANTHINE OXIDASE, of oxypurines such as XANTHINE and HYPOXANTHINE. It is the final oxidation product of purine catabolism in humans and primates, whereas in most other mammals URATE OXIDASE further oxidizes it to ALLANTOIN.
Compounds based on pyrazino[2,3-d]pyrimidine which is a pyrimidine fused to a pyrazine, containing four NITROGEN atoms.
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).
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.
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.
An oxidoreductase that catalyzes the reaction between superoxide anions and hydrogen to yield molecular oxygen and hydrogen peroxide. The enzyme protects the cell against dangerous levels of superoxide. EC 1.15.1.1.
Inorganic compounds that contain the OH- group.
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.
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.
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.
Molecules or ions formed by the incomplete one-electron reduction of oxygen. These reactive oxygen intermediates include SINGLET OXYGEN; SUPEROXIDES; PEROXIDES; HYDROXYL RADICAL; and HYPOCHLOROUS ACID. They contribute to the microbicidal activity of PHAGOCYTES, regulation of signal transduction and gene expression, and the oxidative damage to NUCLEIC ACIDS; PROTEINS; and LIPIDS.
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.
A strong oxidizing agent used in aqueous solution as a ripening agent, bleach, and topical anti-infective. It is relatively unstable and solutions deteriorate over time unless stabilized by the addition of acetanilide or similar organic materials.
The univalent radical OH. Hydroxyl radical is a potent oxidizing agent.
An oxidoreductase that catalyzes the conversion of HYDROGEN PEROXIDE to water and oxygen. It is present in many animal cells. A deficiency of this enzyme results in ACATALASIA.
Substances that influence the course of a chemical reaction by ready combination with free radicals. Among other effects, this combining activity protects pancreatic islets against damage by cytokines and prevents myocardial and pulmonary perfusion injuries.
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.
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)
Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.
The rate dynamics in chemical or physical systems.
A condensation product of riboflavin and adenosine diphosphate. The coenzyme of various aerobic dehydrogenases, e.g., D-amino acid oxidase and L-amino acid oxidase. (Lehninger, Principles of Biochemistry, 1982, p972)
A series of heterocyclic compounds that are variously substituted in nature and are known also as purine bases. They include ADENINE and GUANINE, constituents of nucleic acids, as well as many alkaloids such as CAFFEINE and THEOPHYLLINE. Uric acid is the metabolic end product of purine metabolism.
Dithionite. The dithionous acid ion and its salts.
Inorganic compounds that contain tungsten as an integral part of the molecule.
Compounds or agents that combine with an enzyme in such a manner as to prevent the normal substrate-enzyme combination and the catalytic reaction.
A disturbance in the prooxidant-antioxidant balance in favor of the former, leading to potential damage. Indicators of oxidative stress include damaged DNA bases, protein oxidation products, and lipid peroxidation products (Sies, Oxidative Stress, 1991, pxv-xvi).
A group of oxidoreductases that act on NADH or NADPH. In general, enzymes using NADH or NADPH to reduce a substrate are classified according to the reverse reaction, in which NAD+ or NADP+ is formally regarded as an acceptor. This subclass includes only those enzymes in which some other redox carrier is the acceptor. (Enzyme Nomenclature, 1992, p100) EC 1.6.
Heterocyclic compounds in which an oxygen is attached to a cyclic nitrogen.
Oxidoreductases that are specific for KETONES.
D-Amino-Acid Oxidase is an enzyme that catalyzes the oxidative deamination of D-amino acids to their corresponding α-keto acids, ammonia, and hydrogen peroxide, playing a crucial role in the metabolism of non-proteinogenic D-amino acids.
Naturally occurring or synthetic substances that inhibit or retard the oxidation of a substance to which it is added. They counteract the harmful and damaging effects of oxidation in animal tissues.
Acetophenones are organic compounds that contain a ketone functional group (carbonyl, >C=O) attached to a phenyl ring, making them a subclass of aromatic ketones with the general formula C6H5COCH3.
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)
Ions with the suffix -onium, indicating cations with coordination number 4 of the type RxA+ which are analogous to QUATERNARY AMMONIUM COMPOUNDS (H4N+). Ions include phosphonium R4P+, oxonium R3O+, sulfonium R3S+, chloronium R2Cl+
The art or process of comparing photometrically the relative intensities of the light in different parts of the spectrum.
Gout suppressants that act directly on the renal tubule to increase the excretion of uric acid, thus reducing its concentrations in plasma.
A free radical gas produced endogenously by a variety of mammalian cells, synthesized from ARGININE by NITRIC OXIDE SYNTHASE. Nitric oxide is one of the ENDOTHELIUM-DEPENDENT RELAXING FACTORS released by the vascular endothelium and mediates VASODILATION. It also inhibits platelet aggregation, induces disaggregation of aggregated platelets, and inhibits platelet adhesion to the vascular endothelium. Nitric oxide activates cytosolic GUANYLATE CYCLASE and thus elevates intracellular levels of CYCLIC GMP.
Electron-accepting molecules in chemical reactions in which electrons are transferred from one molecule to another (OXIDATION-REDUCTION).
A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.
An enzyme that converts ascorbic acid to dehydroascorbic acid. EC 1.10.3.3.
Benzaldehydes are aromatic organic compounds consisting of a benzene ring connected to a formyl group (-CHO), which is the simplest and most representative compound being benzaldehyde (C6H5CHO).
Derivatives of the dimethylisoalloxazine (7,8-dimethylbenzo[g]pteridine-2,4(3H,10H)-dione) skeleton. Flavin derivatives serve an electron transfer function as ENZYME COFACTORS in FLAVOPROTEINS.
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.
Proteins that have one or more tightly bound metal ions forming part of their structure. (Dorland, 28th ed)
Oxidoreductases that are specific for ALDEHYDES.
Small molecules that are required for the catalytic function of ENZYMES. Many VITAMINS are coenzymes.
Agents that increase uric acid excretion by the kidney (URICOSURIC AGENTS), decrease uric acid production (antihyperuricemics), or alleviate the pain and inflammation of acute attacks of gout.
A coenzyme composed of ribosylnicotinamide 5'-diphosphate coupled to adenosine 5'-phosphate by pyrophosphate linkage. It is found widely in nature and is involved in numerous enzymatic reactions in which it serves as an electron carrier by being alternately oxidized (NAD+) and reduced (NADH). (Dorland, 27th ed)
Excessive URIC ACID or urate in blood as defined by its solubility in plasma at 37 degrees C; greater than 0.42mmol per liter (7.0mg/dL) in men or 0.36mmol per liter (6.0mg/dL) in women. This condition is caused by overproduction of uric acid or impaired renal clearance. Hyperuricemia can be acquired, drug-induced or genetically determined (LESCH-NYHAN SYNDROME). It is associated with HYPERTENSION and GOUT.
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.
Compounds based on 2-amino-4-hydroxypteridine.
A species of gram-negative, anaerobic, spiral-shaped bacteria originally isolated from a saltwater pond in France. It contains a well-characterized metabolic pathway that enables it to survive transient contacts with OXYGEN.
Peroxidase catalyzed oxidation of lipids using hydrogen peroxide as an electron acceptor.
A plant genus of the family CRASSULACEAE. Members contain rhodioloside. This roseroot is unrelated to the familiar rose (ROSA). Some species in this genus are called stonecrop which is also a common name for SEDUM.
An enzyme that catalyzes the oxidation of cholesterol in the presence of molecular oxygen to 4-cholesten-3-one and hydrogen peroxide. The enzyme is not specific for cholesterol, but will also oxidize other 3-hydroxysteroids. EC 1.1.3.6.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
An enzyme that catalyzes the oxidative deamination of L-amino acids to KETO ACIDS with the generation of AMMONIA and HYDROGEN PEROXIDE. L-amino acid oxidase is widely distributed in and is thought to contribute to the toxicity of SNAKE VENOMS.
Pyruvate oxidase is an enzyme complex located within the mitochondrial matrix that catalyzes the oxidative decarboxylation of pyruvate into acetyl-CoA, thereby linking glycolysis to the citric acid cycle and playing a crucial role in cellular energy production.
Single pavement layer of cells which line the luminal surface of the entire vascular system and regulate the transport of macromolecules and blood components.
Techniques used for determining the values of photometric parameters of light resulting from LUMINESCENCE.
A metallic element with atomic symbol Fe, atomic number 26, and atomic weight 55.85. It is an essential constituent of HEMOGLOBINS; CYTOCHROMES; and IRON-BINDING PROTEINS. It plays a role in cellular redox reactions and in the transport of OXYGEN.
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)
Oxidoreductases with specificity for oxidation or reduction of SULFUR COMPOUNDS.
A hemeprotein from leukocytes. Deficiency of this enzyme leads to a hereditary disorder coupled with disseminated moniliasis. It catalyzes the conversion of a donor and peroxide to an oxidized donor and water. EC 1.11.1.7.
A chelating agent that has been used to mobilize toxic metals from the tissues of humans and experimental animals. It is the main metabolite of DISULFIRAM.
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.
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.
A mammalian pancreatic extract composed of enzymes with protease, amylase and lipase activities. It is used as a digestant in pancreatic malfunction.
A dye used as a reagent in the determination of vitamin C.
A heavy metal trace element with the atomic symbol Cu, atomic number 29, and atomic weight 63.55.
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)
An enzyme of the oxidoreductase class that catalyzes the reaction between catechol and oxygen to yield benzoquinone and water. It is a complex of copper-containing proteins that acts also on a variety of substituted catechols. EC 1.10.3.1.
Molecules which contain an atom or a group of atoms exhibiting an unpaired electron spin that can be detected by electron spin resonance spectroscopy and can be bonded to another molecule. (McGraw-Hill Dictionary of Chemical and Technical Terms, 4th ed)
A membrane-bound flavoenzyme that catalyzes the oxygen-dependent aromatization of protoporphyrinogen IX (Protogen) to protoporphyrin IX (Proto IX). It is the last enzyme of the common branch of the HEME and CHLOROPHYLL pathways in plants, and is the molecular target of diphenyl ether-type herbicides. VARIEGATE PORPHYRIA is an autosomal dominant disorder associated with deficiency of protoporphyrinogen oxidase.
An enzyme that catalyzes the deamination of guanine to form xanthine. EC 3.5.4.3.
A tripeptide with many roles in cells. It conjugates to drugs to make them more soluble for excretion, is a cofactor for some enzymes, is involved in protein disulfide bond rearrangement and reduces peroxides.
Adverse functional, metabolic, or structural changes in ischemic tissues resulting from the restoration of blood flow to the tissue (REPERFUSION), including swelling; HEMORRHAGE; NECROSIS; and damage from FREE RADICALS. The most common instance is MYOCARDIAL REPERFUSION INJURY.
The dialdehyde of malonic acid.
A basic science concerned with the composition, structure, and properties of matter; and the reactions that occur between substances and the associated energy exchange.
Inorganic salts of HYDROGEN CYANIDE containing the -CN radical. The concept also includes isocyanides. It is distinguished from NITRILES, which denotes organic compounds containing the -CN radical.
Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.
The relationship between the dose of an administered drug and the response of the organism to the drug.
A FLAVOPROTEIN, this enzyme catalyzes the oxidation of SARCOSINE to GLYCINE; FORMALDEHYDE; and HYDROGEN PEROXIDE (H2O2).
The composition, conformation, and properties of atoms and molecules, and their reaction and interaction processes.

Role of xanthine oxidase in passive Heymann nephritis in rats. (1/1226)

Passive Heymann nephritis (PHN) in rats is a model of human membranous nephropathy characterized by formation of subepithelial immune deposits in the glomerular capillary wall and complement activation. Oxygen radicals have been implicated in the subsequent glomerular damage which leads to proteinuria. This study examines the involvement of xanthine oxidase in this process. Xanthine oxidase activity was increased nearly twofold in glomeruli isolated 1 and 12 d after induction of PHN, and this was associated with increased glomerular superoxide anion generation. Analysis of glomerular samples by Northern and Western blotting revealed no quantitative changes in xanthine oxidoreductase expression in PHN, suggesting conversion of xanthine dehydrogenase to the oxidase form as the cause of increased activity. Treatment of rats with tungsten, an inhibitor of xanthine oxidase, before induction of PHN resulted in a marked decrease in glomerular xanthine oxidase activity and superoxide anion generation, and decreased proteinuria by 80% (day 12: 423+/-245 mg/d in PHN versus 78+/-53 mg/d in tungsten-treated PHN animals, P < 0.01). These findings point to a pivotal role of xanthine oxidase in the pathophysiology of PHN and could be of importance in the therapy of human membranous nephropathy.  (+info)

Upregulation of superoxide dismutase and nitric oxide synthase mediates the apoptosis-suppressive effects of shear stress on endothelial cells. (2/1226)

Physiological levels of laminar shear stress completely abrogate apoptosis of human endothelial cells in response to a variety of stimuli and might therefore importantly contribute to endothelial integrity. We show here that the apoptosis-suppressive effects of shear stress are mediated by upregulation of Cu/Zn SOD and NO synthase. Shear stress-mediated inhibition of endothelial cell apoptosis in response to exogenous oxygen radicals, oxidized LDL, and tumor necrosis factor-alpha was associated with complete inhibition of caspase-3-like activity, the central effector arm executing the apoptotic cell death program in endothelial cells. Shear stress-dependent upregulation of Cu/Zn SOD and NO synthase blocks activation of the caspase cascade in response to apoptosis-inducing stimuli. These findings establish the upregulation of Cu/Zn SOD and NO synthase by shear stress as a central protective cellular mechanism to preserve the integrity of the endothelium after proapoptotic stimulation.  (+info)

Inhibition of xanthine oxidase and xanthine dehydrogenase by nitric oxide. Nitric oxide converts reduced xanthine-oxidizing enzymes into the desulfo-type inactive form. (3/1226)

Xanthine oxidase (XO) and xanthine dehydrogenase (XDH) were inactivated by incubation with nitric oxide under anaerobic conditions in the presence of xanthine or allopurinol. The inactivation was not pronounced in the absence of an electron donor, indicating that only the reduced enzyme form was inactivated by nitric oxide. The second-order rate constant of the reaction between reduced XO and nitric oxide was determined to be 14.8 +/- 1.4 M-1 s-1 at 25 degrees C. The inactivated enzymes lacked xanthine-dichlorophenolindophenol activity, and the oxypurinol-bound form of XO was partly protected from the inactivation. The absorption spectrum of the inactivated enzyme was not markedly different from that of the normal enzyme. The flavin and iron-sulfur centers of inactivated XO were reduced by dithionite and reoxidized readily with oxygen, and inactivated XDH retained electron transfer activities from NADH to electron acceptors, consistent with the conclusion that the flavin and iron-sulfur centers of the inactivated enzyme both remained intact. Inactivated XO reduced with 6-methylpurine showed no "very rapid" spectra, indicating that the molybdopterin moiety was damaged. Furthermore, inactivated XO reduced by dithionite showed the same slow Mo(V) spectrum as that derived from the desulfo-type enzyme. On the other hand, inactivated XO reduced by dithionite exhibited the same signals for iron-sulfur centers as the normal enzyme. Inactivated XO recovered its activity in the presence of a sulfide-generating system. It is concluded that nitric oxide reacts with an essential sulfur of the reduced molybdenum center of XO and XDH to produce desulfo-type inactive enzymes.  (+info)

Pteridines as inhibitors of xanthine oxidase: structural requirements. (4/1226)

Different pteridine derivatives were investigated for their inhibitory action on xanthine oxidase. From 27 investigated compounds, 13 showed concentration-dependent inhibition of the enzyme. Concentrations necessary for 50% inhibition ranged from <0.1 up to >100 microM. Different types of inhibition were found concerning xanthine and pterin as substrates: competitive, noncompetitive and mixed type. Out of 18 aromatic compounds tested, 12 were inhibitors. Only one out of nine reduced derivatives served as inhibitor. A simple regression model was used to specify the structural requirements for a pteridine to be an inhibitor. The most characteristic features of an inhibitor are aromaticity and no substitution at position 7 of the pteridine ring.  (+info)

Reactive oxygen metabolites increase mitochondrial calcium in endothelial cells: implication of the Ca2+/Na+ exchanger. (5/1226)

In endothelial cells, a bolus of hydrogen peroxide (H2O2) or oxygen metabolites generated by hypoxanthine-xanthine oxidase (HX-XO) increased the mitochondrial calcium concentration [Ca2+]m. Both agents caused a biphasic increase in [Ca2+]m which was preceded by a rise in cytosolic free calcium concentration [Ca2+]c (18 and 6 seconds for H2O2 and HX-XO, respectively). The peak and plateau elevations of [Ca2+] were consistently higher in the mitochondrial matrix than in the cytosol. In Ca2+-free/EGTA medium, the plateau phase of elevated [Ca2+] evoked by H2O2 due to capacitative Ca2+ influx was abolished in the cytosol, but was maintained in the mitochondria. In contrast to H2O2 and HX-XO, ATP which binds the P2Y purinoceptors induced an increase in [Ca2+]m that was similar to that of [Ca2+]c. When cells were first stimulated with inositol 1,4, 5-trisphosphate-generating agonists or the Ca2+-ATPase inhibitor cyclopiazonic acid (CPA), subsequent addition of H2O2 did not affect [Ca2+]c, but still caused an elevation of [Ca2+]m. Moreover, the specific inhibitor of the mitochondrial Ca2+/Na+ exchanger, 7-chloro-3,5-dihydro-5-phenyl-1H-4.1-benzothiazepine-2-on (CGP37157), did not potentiate the effects of H2O2 and HX-XO on [Ca2+]m, while causing a marked increase in the peak [Ca2+]m and a significant attenuation of the rate of [Ca2+]m efflux upon addition of histamine or CPA. In permeabilized cells, H2O2 mimicked the effects of CGP37157 causing an increase in the basal level of matrix free Ca2+ and decreased efflux. Dissipation of the electrochemical proton gradient by carbonylcyanide p-(trifluoromethoxy) phenylhydrazone (FCCP), and blocade of the Ca2+ uptake by ruthenium red prevented [Ca2+]m increases evoked by H2O2. These results demonstrate that the H2O2-induced elevation in [Ca2+]m results from a transfer of Ca2+ secondary to increased [Ca2+]c, and an inhibition of the Ca2+/Na+ electroneutral exchanger of the mitochondria.  (+info)

The superoxide dismutase activity of desulfoferrodoxin from Desulfovibrio desulfuricans ATCC 27774. (6/1226)

Desulfoferrodoxin (Dfx), a small iron protein containing two mononuclear iron centres (designated centre I and II), was shown to complement superoxide dismutase (SOD) deficient mutants of Escherichia coli [Pianzzola, M.J., Soubes M. & Touati, D. (1996) J. Bacteriol. 178, 6736-6742]. Furthermore, neelaredoxin, a protein from Desulfovibrio gigas containing an iron site similar to centre II of Dfx, was recently shown to have a significant SOD activity [Silva, G., Oliveira, S., Gomes, C.M., Pacheco, I., Liu, M.Y., Xavier, A.V., Teixeira, M., Le Gall, J. & Rodrigues-Pousada, C. (1999) Eur. J. Biochem. 259, 235-243]. Thus, the SOD activity of Dfx isolated from the sulphate-reducing bacterium Desulfovibrio desulfuricans ATCC 27774 was studied. The protein exhibits a SOD activity of 70 U x mg-1, which increases approximately 2.5-fold upon incubation with cyanide. Cyanide binds specifically to Dfx centre II, yielding a low-spin iron species with g-values at 2.27 (g perpendicular) and 1.96 (g parallel). Upon reaction of fully oxidized Dfx with the superoxide generating system xanthine/xanthine oxidase, Dfx centres I and II become partially reduced, suggesting that Dfx operates by a redox cycling mechanism, similar to those proposed for other SODs. Evidence for another SOD in D. desulfuricans is also presented - this enzyme is inhibited by cyanide, and N-terminal sequence data strongly indicates that it is an analogue to Cu,Zn-SODs isolated from other sources. This is the first indication that a Cu-containing protein may be present in a sulphate-reducing bacterium.  (+info)

Tissue distribution and characteristics of xanthine oxidase and allopurinol oxidizing enzyme. (7/1226)

Tissue distribution and levels of allopurinol oxidizing enzyme and xanthine oxidase with hypoxanthine as a substrate were compared with supernatant fractions from various tissues of mice and from liver of mice, rats, guinea pigs and rabbits. The allopurinol oxidizing enzyme activities in liver were quite different among the species and the sex difference of the enzyme activity only in mouse liver. In mice, the highest activity of allopurinol oxidizing enzyme was found in the liver with a trace value in lung, but the enzyme activity was not detected in brain, small intestine and kidney, while the highest activity of xanthine oxidase was detected in small intestine, lung, liver and kidney in that sequence. The allopurinol oxidizing enzyme activity in mouse liver supernatant fraction did not change after storage at -20 degrees C or dialysis against 0.1 M Tris-HCl containing 1.15% KCl, but the activity markedly decreased after dialysis against 0.1 M Tris-HCl. On the contrary, the xanthine oxidase was activated 2 to 3 times the usual activity after storage at -20 degrees C or dialysis of the enzyme preparation. These results indicated that allopurinol was hydroxylated to oxipurinol mainly by the enzyme which is not identical to xanthine oxidase in vivo. A possible role of aldehyde oxidase involved in the allopurinol oxidation in liver supernatant fraction was dicussed.  (+info)

Cytosolic Ca2+ movements of endothelial cells exposed to reactive oxygen intermediates: role of hydroxyl radical-mediated redox alteration of cell-membrane Ca2+ channels. (8/1226)

1. The mode of action of reactive oxygen intermediates in cysosolic Ca2+ movements of cultured porcine aortic endothelial cells exposed to xanthine/xanthine oxidase (X/XO) was investigated. 2. Cytosolic Ca2+ movements provoked by X/XO consisted of an initial Ca2+ release from thapsigargin-sensitive intracellular Ca2+ stores and a sustained Ca2+ influx through cell-membrane Ca2+ channels. The Ca2+ movements from both sources were inhibited by catalase, cell-membrane permeable iron chelators (o-phenanthroline and deferoxamine), a *OH scavenger (5,5-dimethyl-1-pyrroline-N-oxide), or an anion channel blocker (disodium 4, 4'-diisothiocyano-2, 2'-stilbenedisulphonic acid), suggesting that *O2- influx through anion channels was responsible for the Ca2+ movements, in which *OH generation catalyzed by intracellular transition metals (i.e., Haber-Weiss cycle) was involved. 3. After an initial Ca2+ elevation provoked by X/XO, cytosolic Ca2+ concentration decreased to a level higher than basal levels. Removal of X/XO slightly enhanced the Ca2+ decrease. Extracellular addition of sulphydryl (SH)-reducing agents, dithiothreitol or glutathione, after the removal of X/XO accelerated the decrement. A Ca2+ channel blocker, Ni2+, abolished the sustained increase in Ca2+, suggesting that Ca2+ influx through cell-membrane Ca2+ channels was extracellularly regulated by the redox state of SH-groups. 4. The X/XO-provoked change in cellular respiration was inhibited by Ni2+ or dithiothreitol as well as inhibitors of Haber-Weiss cycle, suggesting that Ca2+ influx was responsible for *OH-mediated cytotoxicity. We concluded that intracellular *OH generation was involved in the Ca2+ movements in endothelial cells exposed to X/XO. Cytosolic Ca2+ elevation was partly responsible for the oxidants-mediated cytotoxicity.  (+info)

Xanthine oxidase is an enzyme that catalyzes the oxidation of xanthine to uric acid, which is the last step in purine metabolism. It's a type of molybdenum-containing oxidoreductase that generates reactive oxygen species (ROS) during its reaction mechanism.

The enzyme exists in two interconvertible forms: an oxidized state and a reduced state. The oxidized form, called xanthine oxidase, reduces molecular oxygen to superoxide and hydrogen peroxide, while the reduced form, called xanthine dehydrogenase, reduces NAD+ to NADH.

Xanthine oxidase is found in various tissues, including the liver, intestines, and milk. An overproduction of uric acid due to increased activity of xanthine oxidase can lead to hyperuricemia, which may result in gout or kidney stones. Some medications and natural compounds are known to inhibit xanthine oxidase, such as allopurinol and febuxostat, which are used to treat gout and prevent the formation of uric acid stones in the kidneys.

Xanthine is a purine base, which is a naturally occurring heterocyclic aromatic organic compound. It is formed in the body during the metabolism of purines, and it's a normal intermediate in the breakdown of nucleotides to uric acid. Xanthine is also found in various foods and beverages, such as coffee, tea, and chocolate. In the medical field, xanthine may refer to a class of drugs called xanthine derivatives, which include theophylline and caffeine, that act as bronchodilators and cardiac stimulants.

Xanthine dehydrogenase (XDH) is an enzyme involved in the metabolism of purines, which are nitrogen-containing compounds that form part of DNA and RNA. Specifically, XDH helps to break down xanthine and hypoxanthine into uric acid, a waste product that is excreted in the urine.

XDH can exist in two interconvertible forms: a dehydrogenase form (XDH) and an oxidase form (XO). In its dehydrogenase form, XDH uses NAD+ as an electron acceptor to convert xanthine into uric acid. However, when XDH is converted to its oxidase form (XO), it can use molecular oxygen as an electron acceptor instead, producing superoxide and hydrogen peroxide as byproducts. These reactive oxygen species can contribute to oxidative stress and tissue damage in the body.

Abnormal levels or activity of XDH have been implicated in various diseases, including gout, cardiovascular disease, and neurodegenerative disorders.

Xanthines are a type of natural alkaloids that are found in various plants, including tea leaves, cocoa beans, and mate. The most common xanthines are caffeine, theophylline, and theobromine. These compounds have stimulant effects on the central nervous system and are often used in medication to treat conditions such as asthma, bronchitis, and other respiratory issues.

Caffeine is the most widely consumed xanthine and is found in a variety of beverages like coffee, tea, and energy drinks. It works by blocking adenosine receptors in the brain, which can lead to increased alertness and reduced feelings of fatigue.

Theophylline is another xanthine that is used as a bronchodilator to treat asthma and other respiratory conditions. It works by relaxing smooth muscles in the airways, making it easier to breathe.

Theobromine is found in cocoa beans and is responsible for the stimulant effects of chocolate. While it has similar properties to caffeine and theophylline, it is less potent and has a milder effect on the body.

It's worth noting that while xanthines can have beneficial effects when used in moderation, they can also cause negative side effects such as insomnia, nervousness, and rapid heart rate if consumed in large quantities or over an extended period of time.

Allopurinol is a medication used to treat chronic gout and certain types of kidney stones. It works by reducing the production of uric acid in the body, which is the substance that can cause these conditions when it builds up in high levels. Allopurinol is a xanthine oxidase inhibitor, meaning it blocks an enzyme called xanthine oxidase from converting purines into uric acid. By doing this, allopurinol helps to lower the levels of uric acid in the body and prevent the formation of new kidney stones or gout attacks.

It is important to note that allopurinol can have side effects, including rash, stomach upset, and liver or kidney problems. It may also interact with other medications, so it is essential to inform your healthcare provider of any other drugs you are taking before starting allopurinol. Your healthcare provider will determine the appropriate dosage and monitoring schedule based on your individual needs and medical history.

Oxypurinol is not exactly a medical term itself, but it's the main metabolite (a substance that your body makes when it breaks down another substance) of allopurinol, which is a medication commonly used to treat gout and kidney stones. Allopurinol works by reducing the production of uric acid in your body, and oxypurinol helps to continue this effect even after the allopurinol has been metabolized.

So, in a broader medical context, you could define Oxypurinol as:

The primary active metabolite of allopurinol, a medication used to lower uric acid levels in the body, preventing gout attacks and kidney stone formation. Oxypurinol inhibits the enzyme xanthine oxidase, which is responsible for the production of uric acid, thereby reducing the risk of gout and kidney stones.

NADPH oxidase is an enzyme complex that plays a crucial role in the production of reactive oxygen species (ROS) in various cell types. The primary function of NADPH oxidase is to catalyze the transfer of electrons from NADPH to molecular oxygen, resulting in the formation of superoxide radicals. This enzyme complex consists of several subunits, including two membrane-bound components (gp91phox and p22phox) and several cytosolic components (p47phox, p67phox, p40phox, and rac1 or rac2). Upon activation, these subunits assemble to form a functional enzyme complex that generates ROS, which serve as important signaling molecules in various cellular processes. However, excessive or uncontrolled production of ROS by NADPH oxidase has been implicated in the pathogenesis of several diseases, such as cardiovascular disorders, neurodegenerative diseases, and cancer.

Aldehyde oxidase is an enzyme found in the liver and other organs that helps to metabolize (break down) various substances, including drugs, alcohol, and environmental toxins. It does this by catalyzing the oxidation of aldehydes, which are organic compounds containing a functional group consisting of a carbon atom bonded to a hydrogen atom and a double bond to an oxygen atom. Aldehyde oxidase is a member of the molybdenum-containing oxidoreductase family, which also includes xanthine oxidase and sulfite oxidase. These enzymes all contain a molybdenum cofactor that plays a critical role in their catalytic activity.

Aldehyde oxidase is an important enzyme in the metabolism of many drugs, as it can convert them into more water-soluble compounds that can be easily excreted from the body. However, variations in the activity of this enzyme between individuals can lead to differences in drug metabolism and response. Some people may have higher or lower levels of aldehyde oxidase activity, which can affect how quickly they metabolize certain drugs and whether they experience adverse effects.

In addition to its role in drug metabolism, aldehyde oxidase has been implicated in the development of various diseases, including cancer, cardiovascular disease, and neurodegenerative disorders. For example, elevated levels of aldehydes produced by lipid peroxidation have been linked to oxidative stress and inflammation, which can contribute to the progression of these conditions. Aldehyde oxidase may also play a role in the detoxification of environmental pollutants, such as polycyclic aromatic hydrocarbons (PAHs) and heterocyclic amines (HCAs), which have been associated with an increased risk of cancer.

Overall, aldehyde oxidase is an important enzyme that plays a critical role in the metabolism of drugs and other substances, as well as in the development of various diseases. Understanding its activity and regulation may help to develop new strategies for treating or preventing these conditions.

I'm sorry for any confusion, but "Molybdenum" is not a medical term. It is an element with the symbol Mo and atomic number 42 on the periodic table. Molybdenum is used in various industries, including medicine, for example in the production of surgical instruments and some prosthetics due to its strength and resistance to corrosion. However, it is not a term used to describe a medical condition or bodily process. If you have any questions related to elements and their uses in medicine, I'd be happy to help with those!

Hypoxanthine is a purine derivative and an intermediate in the metabolic pathways of nucleotide degradation, specifically adenosine to uric acid in humans. It is formed from the oxidation of xanthine by the enzyme xanthine oxidase. In the body, hypoxanthine is converted to xanthine and then to uric acid, which is excreted in the urine. Increased levels of hypoxanthine in the body can be indicative of various pathological conditions, including tissue hypoxia, ischemia, and necrosis.

Superoxides are partially reduced derivatives of oxygen that contain one extra electron, giving them an overall charge of -1. They are highly reactive and unstable, with the most common superoxide being the hydroxyl radical (•OH-) and the superoxide anion (O2-). Superoxides are produced naturally in the body during metabolic processes, particularly within the mitochondria during cellular respiration. They play a role in various physiological processes, but when produced in excess or not properly neutralized, they can contribute to oxidative stress and damage to cells and tissues, potentially leading to the development of various diseases such as cancer, atherosclerosis, and neurodegenerative disorders.

Hypoxanthine is not a medical condition but a purine base that is a component of many organic compounds, including nucleotides and nucleic acids, which are the building blocks of DNA and RNA. In the body, hypoxanthine is produced as a byproduct of normal cellular metabolism and is converted to xanthine and then uric acid, which is excreted in the urine.

However, abnormally high levels of hypoxanthine in the body can indicate tissue damage or disease. For example, during intense exercise or hypoxia (low oxygen levels), cells may break down ATP (adenosine triphosphate) rapidly, releasing large amounts of hypoxanthine. Similarly, in some genetic disorders such as Lesch-Nyhan syndrome, there is an accumulation of hypoxanthine due to a deficiency of the enzyme that converts it to xanthine. High levels of hypoxanthine can lead to the formation of kidney stones and other complications.

Free radicals are molecules or atoms that have one or more unpaired electrons in their outermost shell, making them highly reactive. They can be formed naturally in the body through processes such as metabolism and exercise, or they can come from external sources like pollution, radiation, and certain chemicals. Free radicals can cause damage to cells and contribute to the development of various diseases, including cancer, cardiovascular disease, and neurodegenerative disorders. Antioxidants are substances that can neutralize free radicals and help protect against their harmful effects.

Medically, "milk" is not defined. However, it is important to note that human babies are fed with breast milk, which is the secretion from the mammary glands of humans. It is rich in nutrients like proteins, fats, carbohydrates (lactose), vitamins and minerals that are essential for growth and development.

Other mammals also produce milk to feed their young. These include cows, goats, and sheep, among others. Their milk is often consumed by humans as a source of nutrition, especially in dairy products. However, the composition of these milks can vary significantly from human breast milk.

Uric acid is a chemical compound that is formed when the body breaks down purines, which are substances that are found naturally in certain foods such as steak, organ meats and seafood, as well as in our own cells. After purines are broken down, they turn into uric acid and then get excreted from the body in the urine.

However, if there is too much uric acid in the body, it can lead to a condition called hyperuricemia. High levels of uric acid can cause gout, which is a type of arthritis that causes painful swelling and inflammation in the joints, especially in the big toe. Uric acid can also form crystals that can collect in the kidneys and lead to kidney stones.

It's important for individuals with gout or recurrent kidney stones to monitor their uric acid levels and follow a treatment plan prescribed by their healthcare provider, which may include medications to lower uric acid levels and dietary modifications.

Pteridines are a class of heterocyclic aromatic organic compounds that are structurally related to pterins, which contain a pyrimidine ring fused to a pyrazine ring. They are naturally occurring substances that can be found in various living organisms such as bacteria, fungi, plants, and animals.

Pteridines have several important biological functions. For instance, they play a crucial role in the synthesis of folate and biotin, which are essential cofactors for various metabolic reactions in the body. Additionally, some pteridines function as chromophores, contributing to the coloration of certain organisms such as butterflies and birds.

In medicine, pteridines have been studied for their potential therapeutic applications. For example, some synthetic pteridine derivatives have shown promising results in preclinical studies as antitumor, antiviral, and antibacterial agents. However, further research is needed to fully understand the medical implications of these compounds.

Oxidation-Reduction (redox) reactions are a type of chemical reaction involving a transfer of electrons between two species. The substance that loses electrons in the reaction is oxidized, and the substance that gains electrons is reduced. Oxidation and reduction always occur together in a redox reaction, hence the term "oxidation-reduction."

In biological systems, redox reactions play a crucial role in many cellular processes, including energy production, metabolism, and signaling. The transfer of electrons in these reactions is often facilitated by specialized molecules called electron carriers, such as nicotinamide adenine dinucleotide (NAD+/NADH) and flavin adenine dinucleotide (FAD/FADH2).

The oxidation state of an element in a compound is a measure of the number of electrons that have been gained or lost relative to its neutral state. In redox reactions, the oxidation state of one or more elements changes as they gain or lose electrons. The substance that is oxidized has a higher oxidation state, while the substance that is reduced has a lower oxidation state.

Overall, oxidation-reduction reactions are fundamental to the functioning of living organisms and are involved in many important biological processes.

Glucose oxidase (GOD) is an enzyme that catalyzes the oxidation of D-glucose to D-glucono-1,5-lactone, while reducing oxygen to hydrogen peroxide in the process. This reaction is a part of the metabolic pathway in some organisms that convert glucose into energy. The systematic name for this enzyme is D-glucose:oxygen 1-oxidoreductase.

Glucose oxidase is commonly found in certain fungi, such as Aspergillus niger, and it has various applications in industry, medicine, and research. For instance, it's used in the production of glucose sensors for monitoring blood sugar levels, in the detection and quantification of glucose in food and beverages, and in the development of biosensors for environmental monitoring.

It's worth noting that while glucose oxidase has many applications, it should not be confused with glutathione peroxidase, another enzyme involved in the reduction of hydrogen peroxide to water.

I'm sorry for any confusion, but 'Tungsten' is not a medical term. It is a chemical element with the symbol W and atomic number 74. Tungsten is a rare metal found naturally on Earth, and it has many industrial uses due to its hardness, high density, and high melting point.

In the context of medicine or healthcare, tungsten may be encountered in certain medical devices, such as X-ray tubes and electrodes, where its properties are utilized for their durability and heat resistance. However, it is not a term that would typically have a formal medical definition.

Medical Definition:

Superoxide dismutase (SOD) is an enzyme that catalyzes the dismutation of superoxide radicals (O2-) into oxygen (O2) and hydrogen peroxide (H2O2). This essential antioxidant defense mechanism helps protect the body's cells from damage caused by reactive oxygen species (ROS), which are produced during normal metabolic processes and can lead to oxidative stress when their levels become too high.

There are three main types of superoxide dismutase found in different cellular locations:
1. Copper-zinc superoxide dismutase (CuZnSOD or SOD1) - Present mainly in the cytoplasm of cells.
2. Manganese superoxide dismutase (MnSOD or SOD2) - Located within the mitochondrial matrix.
3. Extracellular superoxide dismutase (EcSOD or SOD3) - Found in the extracellular spaces, such as blood vessels and connective tissues.

Imbalances in SOD levels or activity have been linked to various pathological conditions, including neurodegenerative diseases, cancer, and aging-related disorders.

Hydroxides are inorganic compounds that contain the hydroxide ion (OH−). They are formed when a base, which is an electron pair donor, reacts with water. The hydroxide ion consists of one oxygen atom and one hydrogen atom, and it carries a negative charge. Hydroxides are basic in nature due to their ability to donate hydroxide ions in solution, which increases the pH and makes the solution more alkaline. Common examples of hydroxides include sodium hydroxide (NaOH), potassium hydroxide (KOH), and calcium hydroxide (Ca(OH)2). They have various applications in industry, medicine, and research.

Monoamine oxidase (MAO) is an enzyme found on the outer membrane of mitochondria in cells throughout the body, but primarily in the gastrointestinal tract, liver, and central nervous system. It plays a crucial role in the metabolism of neurotransmitters and dietary amines by catalyzing the oxidative deamination of monoamines. This enzyme exists in two forms: MAO-A and MAO-B, each with distinct substrate preferences and tissue distributions.

MAO-A preferentially metabolizes serotonin, norepinephrine, and dopamine, while MAO-B is mainly responsible for breaking down phenethylamines and benzylamines, as well as dopamine in some cases. Inhibition of these enzymes can lead to increased neurotransmitter levels in the synaptic cleft, which has implications for various psychiatric and neurological conditions, such as depression and Parkinson's disease. However, MAO inhibitors must be used with caution due to their potential to cause serious adverse effects, including hypertensive crises, when combined with certain foods or medications containing dietary amines or sympathomimetic agents.

Electron Spin Resonance (ESR) Spectroscopy, also known as Electron Paramagnetic Resonance (EPR) Spectroscopy, is a technique used to investigate materials with unpaired electrons. It is based on the principle of absorption of energy by the unpaired electrons when they are exposed to an external magnetic field and microwave radiation.

In this technique, a sample is placed in a magnetic field and microwave radiation is applied. The unpaired electrons in the sample absorb energy and change their spin state when the energy of the microwaves matches the energy difference between the spin states. This absorption of energy is recorded as a function of the magnetic field strength, producing an ESR spectrum.

ESR spectroscopy can provide information about the number, type, and behavior of unpaired electrons in a sample, as well as the local environment around the electron. It is widely used in physics, chemistry, and biology to study materials such as free radicals, transition metal ions, and defects in solids.

Urate oxidase, also known as uricase, is an enzyme that catalyzes the oxidation of uric acid to allantoin. This reaction is an essential part of purine metabolism in many organisms, as allantoin is more soluble and easier to excrete than uric acid. In humans, urate oxidase is non-functional due to mutations in the gene encoding it, which leads to the accumulation of uric acid and predisposes to gout and kidney stones. Urate oxidase is found in some bacteria, fungi, and plants, and can be used as a therapeutic agent in humans to lower serum uric acid levels in conditions such as tumor lysis syndrome and gout.

Reactive Oxygen Species (ROS) are highly reactive molecules containing oxygen, including peroxides, superoxide, hydroxyl radical, and singlet oxygen. They are naturally produced as byproducts of normal cellular metabolism in the mitochondria, and can also be generated by external sources such as ionizing radiation, tobacco smoke, and air pollutants. At low or moderate concentrations, ROS play important roles in cell signaling and homeostasis, but at high concentrations, they can cause significant damage to cell structures, including lipids, proteins, and DNA, leading to oxidative stress and potential cell death.

Protein-Lysine 6-Oxidase (PLOX) is an enzyme that belongs to the family of copper-containing oxidases. It catalyzes the oxidative deamination of specific lysine residues in proteins, resulting in the formation of lysine-6-aldehydes, ammonia, and hydrogen peroxide. This enzyme plays a crucial role in various biological processes, including the regulation of protein function, modification of extracellular matrices, and the maintenance of copper homeostasis. Mutations in the gene encoding PLOX have been associated with certain diseases, such as Menkes disease, a rare X-linked recessive disorder characterized by copper deficiency and neurological symptoms.

Hydrogen peroxide (H2O2) is a colorless, odorless, clear liquid with a slightly sweet taste, although drinking it is harmful and can cause poisoning. It is a weak oxidizing agent and is used as an antiseptic and a bleaching agent. In diluted form, it is used to disinfect wounds and kill bacteria and viruses on the skin; in higher concentrations, it can be used to bleach hair or remove stains from clothing. It is also used as a propellant in rocketry and in certain industrial processes. Chemically, hydrogen peroxide is composed of two hydrogen atoms and two oxygen atoms, and it is structurally similar to water (H2O), with an extra oxygen atom. This gives it its oxidizing properties, as the additional oxygen can be released and used to react with other substances.

A hydroxyl radical is defined in biochemistry and medicine as an extremely reactive species, characterized by the presence of an oxygen atom bonded to a hydrogen atom (OH-). It is formed when a water molecule (H2O) is split into a hydroxide ion (OH-) and a hydrogen ion (H+) in the process of oxidation.

In medical terms, hydroxyl radicals are important in understanding free radical damage and oxidative stress, which can contribute to the development of various diseases, including cancer, cardiovascular disease, and neurodegenerative disorders. They are also involved in the body's natural defense mechanisms against pathogens. However, an overproduction of hydroxyl radicals can cause damage to cellular components such as DNA, proteins, and lipids, leading to cell dysfunction and death.

Catalase is a type of enzyme that is found in many living organisms, including humans. Its primary function is to catalyze the decomposition of hydrogen peroxide (H2O2) into water (H2O) and oxygen (O2). This reaction helps protect cells from the harmful effects of hydrogen peroxide, which can be toxic at high concentrations.

The chemical reaction catalyzed by catalase can be represented as follows:

H2O2 + Catalase → H2O + O2 + Catalase

Catalase is a powerful antioxidant enzyme that plays an important role in protecting cells from oxidative damage. It is found in high concentrations in tissues that produce or are exposed to hydrogen peroxide, such as the liver, kidneys, and erythrocytes (red blood cells).

Deficiency in catalase activity has been linked to several diseases, including cancer, neurodegenerative disorders, and aging. On the other hand, overexpression of catalase has been shown to have potential therapeutic benefits in various disease models, such as reducing inflammation and oxidative stress.

Free radical scavengers, also known as antioxidants, are substances that neutralize or stabilize free radicals. Free radicals are highly reactive atoms or molecules with unpaired electrons, capable of causing damage to cells and tissues in the body through a process called oxidative stress. Antioxidants donate an electron to the free radical, thereby neutralizing it and preventing it from causing further damage. They can be found naturally in foods such as fruits, vegetables, and nuts, or they can be synthesized and used as dietary supplements. Examples of antioxidants include vitamins C and E, beta-carotene, and selenium.

Oxygen is a colorless, odorless, tasteless gas that constitutes about 21% of the earth's atmosphere. It is a crucial element for human and most living organisms as it is vital for respiration. Inhaled oxygen enters the lungs and binds to hemoglobin in red blood cells, which carries it to tissues throughout the body where it is used to convert nutrients into energy and carbon dioxide, a waste product that is exhaled.

Medically, supplemental oxygen therapy may be provided to patients with conditions such as chronic obstructive pulmonary disease (COPD), pneumonia, heart failure, or other medical conditions that impair the body's ability to extract sufficient oxygen from the air. Oxygen can be administered through various devices, including nasal cannulas, face masks, and ventilators.

Oxidoreductases are a class of enzymes that catalyze oxidation-reduction reactions, which involve the transfer of electrons from one molecule (the reductant) to another (the oxidant). These enzymes play a crucial role in various biological processes, including energy production, metabolism, and detoxification.

The oxidoreductase-catalyzed reaction typically involves the donation of electrons from a reducing agent (donor) to an oxidizing agent (acceptor), often through the transfer of hydrogen atoms or hydride ions. The enzyme itself does not undergo any permanent chemical change during this process, but rather acts as a catalyst to lower the activation energy required for the reaction to occur.

Oxidoreductases are classified and named based on the type of electron donor or acceptor involved in the reaction. For example, oxidoreductases that act on the CH-OH group of donors are called dehydrogenases, while those that act on the aldehyde or ketone groups are called oxidases. Other examples include reductases, peroxidases, and catalases.

Understanding the function and regulation of oxidoreductases is important for understanding various physiological processes and developing therapeutic strategies for diseases associated with impaired redox homeostasis, such as cancer, neurodegenerative disorders, and cardiovascular disease.

"Cattle" is a term used in the agricultural and veterinary fields to refer to domesticated animals of the genus *Bos*, primarily *Bos taurus* (European cattle) and *Bos indicus* (Zebu). These animals are often raised for meat, milk, leather, and labor. They are also known as bovines or cows (for females), bulls (intact males), and steers/bullocks (castrated males). However, in a strict medical definition, "cattle" does not apply to humans or other animals.

In the context of medicine and pharmacology, "kinetics" refers to the study of how a drug moves throughout the body, including its absorption, distribution, metabolism, and excretion (often abbreviated as ADME). This field is called "pharmacokinetics."

1. Absorption: This is the process of a drug moving from its site of administration into the bloodstream. Factors such as the route of administration (e.g., oral, intravenous, etc.), formulation, and individual physiological differences can affect absorption.

2. Distribution: Once a drug is in the bloodstream, it gets distributed throughout the body to various tissues and organs. This process is influenced by factors like blood flow, protein binding, and lipid solubility of the drug.

3. Metabolism: Drugs are often chemically modified in the body, typically in the liver, through processes known as metabolism. These changes can lead to the formation of active or inactive metabolites, which may then be further distributed, excreted, or undergo additional metabolic transformations.

4. Excretion: This is the process by which drugs and their metabolites are eliminated from the body, primarily through the kidneys (urine) and the liver (bile).

Understanding the kinetics of a drug is crucial for determining its optimal dosing regimen, potential interactions with other medications or foods, and any necessary adjustments for special populations like pediatric or geriatric patients, or those with impaired renal or hepatic function.

Flavin-Adenine Dinucleotide (FAD) is a coenzyme that plays a crucial role in various metabolic processes, particularly in the electron transport chain where it functions as an electron carrier in oxidation-reduction reactions. FAD is composed of a flavin moiety, riboflavin or vitamin B2, and adenine dinucleotide. It can exist in two forms: an oxidized form (FAD) and a reduced form (FADH2). The reduction of FAD to FADH2 involves the gain of two electrons and two protons, which is accompanied by a significant conformational change that allows FADH2 to donate its electrons to subsequent components in the electron transport chain, ultimately leading to the production of ATP, the main energy currency of the cell.

Purines are heterocyclic aromatic organic compounds that consist of a pyrimidine ring fused to an imidazole ring. They are fundamental components of nucleotides, which are the building blocks of DNA and RNA. In the body, purines can be synthesized endogenously or obtained through dietary sources such as meat, seafood, and certain vegetables.

Once purines are metabolized, they are broken down into uric acid, which is excreted by the kidneys. Elevated levels of uric acid in the body can lead to the formation of uric acid crystals, resulting in conditions such as gout or kidney stones. Therefore, maintaining a balanced intake of purine-rich foods and ensuring proper kidney function are essential for overall health.

Dithionite is a chemical compound with the formula Na2S2O4. It is also known as sodium hydrosulfite or sodium dithionite. Dithionite is a white crystalline solid that is highly soluble in water and is commonly used as a reducing agent in various industrial and laboratory applications, including the reduction of iron and copper salts, the bleaching of textiles and pulp, and the removal of sulfur dioxide from flue gases.

In medical contexts, dithionite may be used as a reducing agent in some pharmaceutical preparations or as an antidote for certain types of poisoning. However, it is important to note that dithionite can be toxic and corrosive in concentrated forms, and should be handled with care.

Tungsten compounds refer to chemical substances that contain tungsten (W, atomic number 74) in its ionic or molecular form. Tungsten is a heavy metal and exists in several oxidation states, most commonly +6, +4, and +2. Tungsten compounds have various applications in industrial, medical, and technological fields.

Examples of tungsten compounds include:

* Tungstic acid (WO3·2H2O)
* Sodium polytungstate (Na6WO6)
* Calcium tungstate (CaWO4)
* Tungsten carbide (WC)
* Tungsten hexafluoride (WF6)

Tungsten compounds have been used in medical imaging, such as X-ray machines and CT scanners, due to their high density and ability to absorb X-rays. They are also used in the production of surgical instruments, dental alloys, and other medical devices. However, some tungsten compounds can be toxic or carcinogenic, so proper handling and disposal are essential.

Enzyme inhibitors are substances that bind to an enzyme and decrease its activity, preventing it from catalyzing a chemical reaction in the body. They can work by several mechanisms, including blocking the active site where the substrate binds, or binding to another site on the enzyme to change its shape and prevent substrate binding. Enzyme inhibitors are often used as drugs to treat various medical conditions, such as high blood pressure, abnormal heart rhythms, and bacterial infections. They can also be found naturally in some foods and plants, and can be used in research to understand enzyme function and regulation.

Oxidative stress is defined as an imbalance between the production of reactive oxygen species (free radicals) and the body's ability to detoxify them or repair the damage they cause. This imbalance can lead to cellular damage, oxidation of proteins, lipids, and DNA, disruption of cellular functions, and activation of inflammatory responses. Prolonged or excessive oxidative stress has been linked to various health conditions, including cancer, cardiovascular diseases, neurodegenerative disorders, and aging-related diseases.

NADH, NADPH oxidoreductases are a class of enzymes that catalyze the redox reaction between NADH or NADPH and various electron acceptors. These enzymes play a crucial role in cellular metabolism by transferring electrons from NADH or NADPH to other molecules, which is essential for many biochemical reactions.

NADH (nicotinamide adenine dinucleotide hydrogen) and NADPH (nicotinamide adenine dinucleotide phosphate hydrogen) are coenzymes that act as electron carriers in redox reactions. They consist of a nicotinamide ring, which undergoes reduction or oxidation by accepting or donating electrons and a proton (H+).

NADH, NADPH oxidoreductases are classified based on their structure and mechanism of action. Some examples include:

1. Dehydrogenases: These enzymes catalyze the oxidation of NADH or NADPH to NAD+ or NADP+ while reducing an organic substrate. Examples include lactate dehydrogenase, alcohol dehydrogenase, and malate dehydrogenase.
2. Oxidases: These enzymes catalyze the oxidation of NADH or NADPH to NAD+ or NADP+ while reducing molecular oxygen (O2) to water (H2O). Examples include NADH oxidase and NADPH oxidase.
3. Reductases: These enzymes catalyze the reduction of various electron acceptors using NADH or NADPH as a source of electrons. Examples include glutathione reductase, thioredoxin reductase, and nitrate reductase.

Overall, NADH, NADPH oxidoreductases are essential for maintaining the redox balance in cells and play a critical role in various metabolic pathways, including energy production, detoxification, and biosynthesis.

Cyclic N-oxides are a class of organic compounds that contain a cyclic structure with a nitrogen atom bonded to an oxygen atom as an N-oxide. An N-oxide is a compound in which the nitrogen atom has a positive charge and the oxygen atom has a negative charge, forming a polar covalent bond. In cyclic N-oxides, this N-O group is part of a ring structure, which can be composed of various combinations of carbon, nitrogen, and other atoms. These compounds have been studied for their potential use in pharmaceuticals, agrochemicals, and materials science.

Ketone oxidoreductases are a group of enzymes that catalyze the conversion of ketones to corresponding alcohols or vice versa, through the process of reduction or oxidation. These enzymes play an essential role in various metabolic pathways and biochemical reactions within living organisms.

In the context of medical research and diagnostics, ketone oxidoreductases have gained attention for their potential applications in the development of biosensors to detect and monitor blood ketone levels, particularly in patients with diabetes. Elevated levels of ketones in the blood (known as ketonemia) can indicate a serious complication called diabetic ketoacidosis, which requires prompt medical attention.

One example of a ketone oxidoreductase is the enzyme known as d-beta-hydroxybutyrate dehydrogenase (d-BDH), which catalyzes the conversion of d-beta-hydroxybutyrate to acetoacetate. This reaction is part of the metabolic pathway that breaks down fatty acids for energy production, and it becomes particularly important during periods of low carbohydrate availability or insulin deficiency, as seen in diabetes.

Understanding the function and regulation of ketone oxidoreductases can provide valuable insights into the pathophysiology of metabolic disorders like diabetes and contribute to the development of novel therapeutic strategies for their management.

D-amino-acid oxidase (DAAO) is an enzyme that catalyzes the oxidative deamination of D-amino acids to their corresponding α-keto acids, ammonia, and hydrogen peroxide. This enzyme plays a crucial role in the metabolism of D-amino acids in various organisms, including humans. In humans, DAAO is primarily expressed in the brain and contributes to the regulation of neurotransmitter levels and other physiological processes. Genetic variations and dysregulation of DAAO have been implicated in several neurological disorders, such as schizophrenia and bipolar disorder.

Antioxidants are substances that can prevent or slow damage to cells caused by free radicals, which are unstable molecules that the body produces as a reaction to environmental and other pressures. Antioxidants are able to neutralize free radicals by donating an electron to them, thus stabilizing them and preventing them from causing further damage to the cells.

Antioxidants can be found in a variety of foods, including fruits, vegetables, nuts, and grains. Some common antioxidants include vitamins C and E, beta-carotene, and selenium. Antioxidants are also available as dietary supplements.

In addition to their role in protecting cells from damage, antioxidants have been studied for their potential to prevent or treat a number of health conditions, including cancer, heart disease, and age-related macular degeneration. However, more research is needed to fully understand the potential benefits and risks of using antioxidant supplements.

Acetophenones are organic compounds that consist of a phenyl group (a benzene ring with a hydroxyl group replaced by a hydrogen atom) bonded to an acetyl group (a carbonyl group bonded to a methyl group). The chemical structure can be represented as CH3COC6H5.

Acetophenones are aromatic ketones and can be found in essential oils of various plants, as well as in some synthetic fragrances. They have a characteristic sweet, fruity odor and are used in the perfume industry. In addition to their use as fragrances, acetophenones have been studied for their potential medicinal properties, including anti-inflammatory, antimicrobial, and analgesic effects. However, more research is needed before they can be considered safe and effective for medical use.

Monoamine oxidase inhibitors (MAOIs) are a class of drugs that work by blocking the action of monoamine oxidase, an enzyme found in the brain and other organs of the body. This enzyme is responsible for breaking down certain neurotransmitters, such as serotonin, dopamine, and norepinephrine, which are chemicals that transmit signals in the brain.

By inhibiting the action of monoamine oxidase, MAOIs increase the levels of these neurotransmitters in the brain, which can help to alleviate symptoms of depression and other mood disorders. However, MAOIs also affect other chemicals in the body, including tyramine, a substance found in some foods and beverages, as well as certain medications. As a result, MAOIs can have serious side effects and interactions with other substances, making them a less commonly prescribed class of antidepressants than other types of drugs.

MAOIs are typically used as a last resort when other treatments for depression have failed, due to their potential for dangerous interactions and side effects. They require careful monitoring and dosage adjustment by a healthcare provider, and patients must follow strict dietary restrictions while taking them.

'Onium compounds' is a general term used in chemistry and biochemistry to describe a class of organic compounds that contain a positively charged functional group. The name 'onium' refers to the positive charge, which is usually located on a nitrogen or phosphorus atom.

The most common onium compounds are ammonium compounds (positive charge on a nitrogen atom) and phosphonium compounds (positive charge on a phosphorus atom). Other examples include sulfonium compounds (positive charge on a sulfur atom) and oxonium compounds (positive charge on an oxygen atom).

In the context of medical research, onium compounds may be studied for their potential use as drugs or diagnostic agents. For example, certain ammonium compounds have been shown to have antimicrobial properties and are used in some disinfectants and sanitizers. Phosphonium compounds have been investigated for their potential use as anti-cancer agents, while sulfonium compounds have been studied for their potential as enzyme inhibitors.

It's worth noting that onium compounds can also be found in nature, including in some biological systems. For example, certain enzymes and signaling molecules contain onium groups that are important for their function.

Spectrophotometry is a technical analytical method used in the field of medicine and science to measure the amount of light absorbed or transmitted by a substance at specific wavelengths. This technique involves the use of a spectrophotometer, an instrument that measures the intensity of light as it passes through a sample.

In medical applications, spectrophotometry is often used in laboratory settings to analyze various biological samples such as blood, urine, and tissues. For example, it can be used to measure the concentration of specific chemicals or compounds in a sample by measuring the amount of light that is absorbed or transmitted at specific wavelengths.

In addition, spectrophotometry can also be used to assess the properties of biological tissues, such as their optical density and thickness. This information can be useful in the diagnosis and treatment of various medical conditions, including skin disorders, eye diseases, and cancer.

Overall, spectrophotometry is a valuable tool for medical professionals and researchers seeking to understand the composition and properties of various biological samples and tissues.

Uricosuric agents are a class of medications that work by increasing the excretion of uric acid through the kidneys, thereby reducing the levels of uric acid in the blood. This helps to prevent the formation of uric acid crystals, which can cause joint inflammation and damage leading to conditions such as gout.

Uricosuric agents achieve this effect by inhibiting the reabsorption of uric acid in the kidney tubules or by increasing its secretion into the urine. Examples of uricosuric agents include probenecid, sulfinpyrazone, and benzbromarone. These medications are typically used to manage chronic gout and hyperuricemia (elevated levels of uric acid in the blood). It is important to note that uricosuric agents may increase the risk of kidney stones due to increased excretion of uric acid in the urine, so it is essential to maintain adequate hydration while taking these medications.

Nitric oxide (NO) is a molecule made up of one nitrogen atom and one oxygen atom. In the body, it is a crucial signaling molecule involved in various physiological processes such as vasodilation, immune response, neurotransmission, and inhibition of platelet aggregation. It is produced naturally by the enzyme nitric oxide synthase (NOS) from the amino acid L-arginine. Inhaled nitric oxide is used medically to treat pulmonary hypertension in newborns and adults, as it helps to relax and widen blood vessels, improving oxygenation and blood flow.

Medical definitions of "oxidants" refer to them as oxidizing agents or substances that can gain electrons and be reduced. They are capable of accepting electrons from other molecules in chemical reactions, leading to the production of oxidation products. In biological systems, oxidants play a crucial role in various cellular processes such as energy production and immune responses. However, an imbalance between oxidant and antioxidant levels can lead to a state of oxidative stress, which has been linked to several diseases, including cancer, cardiovascular disease, and neurodegenerative disorders. Examples of oxidants include reactive oxygen species (ROS), such as superoxide anion, hydrogen peroxide, and hydroxyl radical, as well as reactive nitrogen species (RNS), such as nitric oxide and peroxynitrite.

The liver is a large, solid organ located in the upper right portion of the abdomen, beneath the diaphragm and above the stomach. It plays a vital role in several bodily functions, including:

1. Metabolism: The liver helps to metabolize carbohydrates, fats, and proteins from the food we eat into energy and nutrients that our bodies can use.
2. Detoxification: The liver detoxifies harmful substances in the body by breaking them down into less toxic forms or excreting them through bile.
3. Synthesis: The liver synthesizes important proteins, such as albumin and clotting factors, that are necessary for proper bodily function.
4. Storage: The liver stores glucose, vitamins, and minerals that can be released when the body needs them.
5. Bile production: The liver produces bile, a digestive juice that helps to break down fats in the small intestine.
6. Immune function: The liver plays a role in the immune system by filtering out bacteria and other harmful substances from the blood.

Overall, the liver is an essential organ that plays a critical role in maintaining overall health and well-being.

Ascorbate oxidase is an enzyme that catalyzes the oxidation of ascorbic acid (vitamin C) to dehydroascorbic acid in the presence of oxygen. This reaction also results in the production of water and hydrogen peroxide as byproducts. Ascorbate oxidase plays a significant role in regulating the levels of ascorbic acid in plants, where it is primarily found. It belongs to the family of copper-containing oxidoreductases. The enzyme's active site contains two copper ions that facilitate the electron transfer during the catalytic process. Ascorbate oxidase is not considered essential for human health since humans do not produce ascorbic acid and must obtain it through dietary sources.

Benzaldehyde is an organic compound with the formula C6H5CHO. It is the simplest aromatic aldehyde, and it consists of a benzene ring attached to a formyl group. Benzaldehyde is a colorless liquid with a characteristic almond-like odor.

Benzaldehyde occurs naturally in various plants, including bitter almonds, cherries, peaches, and apricots. It is used in many industrial applications, such as in the production of perfumes, flavorings, and dyes. In addition, benzaldehyde has been used in medical research for its potential therapeutic effects, such as its anti-inflammatory and antimicrobial properties.

However, it is important to note that benzaldehyde can be toxic in high concentrations and may cause irritation to the skin, eyes, and respiratory system. Therefore, it should be handled with care and used in accordance with appropriate safety guidelines.

Flavins are a group of naturally occurring organic compounds that contain a characteristic isoalloxazine ring, which is a tricyclic aromatic structure. The most common and well-known flavin is flavin adenine dinucleotide (FAD), which plays a crucial role as a coenzyme in various biological oxidation-reduction reactions. FAD accepts electrons and hydrogens to form the reduced form, flavin adenine dinucleotide hydride (FADH2). Another important flavin is flavin mononucleotide (FMN), which is derived from FAD and functions similarly as a coenzyme. Flavins are yellow in color and can be found in various biological systems, including animals, plants, and microorganisms. They are involved in several metabolic pathways, such as the electron transport chain, where they contribute to energy production.

Galactose oxidase is an enzyme with the systematic name D-galactose:oxygen oxidoreductase. It is found in certain fungi and bacteria, and it catalyzes the following reaction:

D-galactose + O2 -> D-galacto-hexodialdose + H2O2

In this reaction, the enzyme oxidizes the hydroxyl group (-OH) on the sixth carbon atom of D-galactose to an aldehyde group (-CHO), forming D-galacto-hexodialdose. At the same time, it reduces molecular oxygen (O2) to hydrogen peroxide (H2O2).

Galactose oxidase is a copper-containing enzyme and requires the cofactor molybdenum for its activity. It has potential applications in various industrial processes, such as the production of D-galacto-hexodialdose and other sugar derivatives, as well as in biosensors for detecting glucose levels in biological samples.

Metalloproteins are proteins that contain one or more metal ions as a cofactor, which is required for their biological activity. These metal ions play crucial roles in the catalytic function, structural stability, and electron transfer processes of metalloproteins. The types of metals involved can include iron, zinc, copper, magnesium, calcium, or manganese, among others. Examples of metalloproteins are hemoglobin (contains heme-bound iron), cytochrome c (contains heme-bound iron and functions in electron transfer), and carbonic anhydrase (contains zinc and catalyzes the conversion between carbon dioxide and bicarbonate).

Aldehyde oxidoreductases are a class of enzymes that catalyze the oxidation of aldehydes to carboxylic acids using NAD+ or FAD as cofactors. They play a crucial role in the detoxification of aldehydes generated from various metabolic processes, such as lipid peroxidation and alcohol metabolism. These enzymes are widely distributed in nature and have been identified in bacteria, yeast, plants, and animals.

The oxidation reaction catalyzed by aldehyde oxidoreductases involves the transfer of electrons from the aldehyde substrate to the cofactor, resulting in the formation of a carboxylic acid and reduced NAD+ or FAD. The enzymes are classified into several families based on their sequence similarity and cofactor specificity.

One of the most well-known members of this family is alcohol dehydrogenase (ADH), which catalyzes the oxidation of alcohols to aldehydes or ketones as part of the alcohol metabolism pathway. Another important member is aldehyde dehydrogenase (ALDH), which further oxidizes the aldehydes generated by ADH to carboxylic acids, thereby preventing the accumulation of toxic aldehydes in the body.

Deficiencies in ALDH enzymes have been linked to several human diseases, including alcoholism and certain types of cancer. Therefore, understanding the structure and function of aldehyde oxidoreductases is essential for developing new therapeutic strategies to treat these conditions.

Coenzymes are small organic molecules that assist enzymes in catalyzing chemical reactions within cells. They typically act as carriers of specific atoms or groups of atoms during enzymatic reactions, facilitating the conversion of substrates into products. Coenzymes often bind temporarily to enzymes at the active site, forming an enzyme-coenzyme complex.

Coenzymes are usually derived from vitamins or minerals and are essential for maintaining proper metabolic functions in the body. Examples of coenzymes include nicotinamide adenine dinucleotide (NAD+), flavin adenine dinucleotide (FAD), and coenzyme A (CoA). When a coenzyme is used up in a reaction, it must be regenerated or replaced for the enzyme to continue functioning.

In summary, coenzymes are vital organic compounds that work closely with enzymes to facilitate biochemical reactions, ensuring the smooth operation of various metabolic processes within living organisms.

Gout suppressants are a type of medication used to treat acute gout attacks and reduce the risk of future episodes. They work by decreasing the production of uric acid in the body or improving its elimination, thereby reducing the formation of uric acid crystals that cause inflammation and pain in the joints. Common examples of gout suppressants include:

1. Colchicine: This medication is often used to treat acute gout attacks by reducing inflammation and swelling in the affected joint. It should be taken as soon as possible after the onset of symptoms for best results.

2. Nonsteroidal anti-inflammatory drugs (NSAIDs): These medications, such as ibuprofen, naproxen, and celecoxib, can help alleviate pain and inflammation during an acute gout attack. They are usually more effective when taken at the first sign of an attack.

3. Corticosteroids: In some cases, corticosteroid medications like prednisone may be prescribed to treat severe gout attacks that do not respond to other treatments. These drugs can be administered orally or injected directly into the affected joint.

4. Allopurinol and febuxostat: These medications are called xanthine oxidase inhibitors, which reduce uric acid production in the body. They are typically used for chronic gout management to prevent future attacks and lower the risk of complications such as kidney stones and joint damage.

It is important to note that some gout suppressants may have side effects or interact with other medications, so it is crucial to discuss any concerns with a healthcare provider before starting treatment. Additionally, lifestyle changes such as maintaining a healthy weight, following a low-purine diet, and staying hydrated can help manage gout symptoms and lower the risk of future attacks.

NAD (Nicotinamide Adenine Dinucleotide) is a coenzyme found in all living cells. It plays an essential role in cellular metabolism, particularly in redox reactions, where it acts as an electron carrier. NAD exists in two forms: NAD+, which accepts electrons and becomes reduced to NADH. This pairing of NAD+/NADH is involved in many fundamental biological processes such as generating energy in the form of ATP during cellular respiration, and serving as a critical cofactor for various enzymes that regulate cellular functions like DNA repair, gene expression, and cell death.

Maintaining optimal levels of NAD+/NADH is crucial for overall health and longevity, as it declines with age and in certain disease states. Therefore, strategies to boost NAD+ levels are being actively researched for their potential therapeutic benefits in various conditions such as aging, neurodegenerative disorders, and metabolic diseases.

Hyperuricemia is a medical condition characterized by an excessively high level of uric acid in the blood. Uric acid is a waste product that's produced when the body breaks down purines, which are substances found in certain foods and drinks, such as red meat, seafood, and alcoholic beverages. Normally, uric acid is dissolved in the blood and then excreted by the kidneys through urine. However, if there's too much uric acid in the body or if the kidneys can't eliminate it efficiently, it can build up in the blood, leading to hyperuricemia.

Mild cases of hyperuricemia may not cause any symptoms and may not require treatment. However, high levels of uric acid can lead to the formation of uric acid crystals, which can accumulate in the joints and tissues, causing inflammation and pain. This condition is known as gout. Hyperuricemia can also increase the risk of developing kidney stones and kidney disease.

Hyperuricemia can be caused by several factors, including a diet high in purines, genetic factors, kidney disease, certain medications, and conditions that cause rapid cell turnover, such as cancer or psoriasis. Treatment for hyperuricemia typically involves lifestyle changes, such as reducing the intake of purine-rich foods and beverages, maintaining a healthy weight, and staying hydrated. Medications may also be prescribed to lower uric acid levels in the blood and prevent gout attacks.

Acyl-CoA oxidase is an enzyme that plays a crucial role in the breakdown of fatty acids within the body. It is located in the peroxisomes, which are small organelles found in the cells of living organisms. The primary function of acyl-CoA oxidase is to catalyze the initial step in the beta-oxidation of fatty acids, a process that involves the sequential removal of two-carbon units from fatty acid molecules in the form of acetyl-CoA.

The reaction catalyzed by acyl-CoA oxidase is as follows:

acyl-CoA + FAD → trans-2,3-dehydroacyl-CoA + FADH2 + H+

In this reaction, the enzyme removes a hydrogen atom from the fatty acyl-CoA molecule and transfers it to its cofactor, flavin adenine dinucleotide (FAD). This results in the formation of trans-2,3-dehydroacyl-CoA, FADH2, and a proton. The FADH2 produced during this reaction can then be used to generate ATP through the electron transport chain, while the trans-2,3-dehydroacyl-CoA undergoes further reactions in the beta-oxidation pathway.

There are two main isoforms of acyl-CoA oxidase found in humans: ACOX1 and ACOX2. ACOX1 is primarily responsible for oxidizing straight-chain fatty acids, while ACOX2 specializes in the breakdown of branched-chain fatty acids. Mutations in the genes encoding these enzymes can lead to various metabolic disorders, such as peroxisomal biogenesis disorders and Refsum disease.

Pterins are a group of naturally occurring pigments that are derived from purines. They are widely distributed in various organisms, including bacteria, fungi, and animals. In humans, pterins are primarily found in the eye, skin, and hair. Some pterins have been found to play important roles as cofactors in enzymatic reactions and as electron carriers in metabolic pathways.

Abnormal levels of certain pterins can be indicative of genetic disorders or other medical conditions. For example, an excess of biopterin, a type of pterin, is associated with phenylketonuria (PKU), a genetic disorder that affects the body's ability to metabolize the amino acid phenylalanine. Similarly, low levels of neopterin, another type of pterin, can be indicative of immune system dysfunction or certain types of cancer.

Medical professionals may measure pterin levels in blood, urine, or other bodily fluids to help diagnose and monitor these conditions.

'Desulfovibrio gigas' is a species of bacteria that belongs to the family Desulfovibrionaceae. These bacteria are gram-negative, curved rods and are commonly found in aquatic environments such as freshwater and marine sediments. They are capable of reducing sulfate to sulfide and are important organisms in the sulfur cycle in nature. 'Desulfovibrio gigas' is also known for its ability to grow under extreme conditions, such as high temperatures and pressures, making it a subject of interest in astrobiology and the search for extraterrestrial life.

It is worth noting that while this bacterium has been extensively studied in the field of microbiology, there may not be a specific medical definition associated with it, as it does not directly cause any known human diseases. However, understanding the physiology and metabolism of such extremophilic bacteria can provide insights into the limits of life and the potential for survival in extreme environments, both on Earth and beyond.

Lipid peroxidation is a process in which free radicals, such as reactive oxygen species (ROS), steal electrons from lipids containing carbon-carbon double bonds, particularly polyunsaturated fatty acids (PUFAs). This results in the formation of lipid hydroperoxides, which can decompose to form a variety of compounds including reactive carbonyl compounds, aldehydes, and ketones.

Malondialdehyde (MDA) is one such compound that is commonly used as a marker for lipid peroxidation. Lipid peroxidation can cause damage to cell membranes, leading to changes in their fluidity and permeability, and can also result in the modification of proteins and DNA, contributing to cellular dysfunction and ultimately cell death. It is associated with various pathological conditions such as atherosclerosis, neurodegenerative diseases, and cancer.

Rhodiola (Rhodiola rosea), also known as golden root or roseroot, is an herb that grows in the wild Arctic regions of Europe and Asia. It has been used in traditional medicine in Russia and Scandinavia for centuries to increase stamina, strength, and mental capacity, and to help cope with cold climates and high altitudes.

Rhodiola rosea contains several chemical compounds, including rosavins and salidroside, which are believed to have adaptogenic properties, meaning they may help the body better respond to physical, chemical, and environmental stress. Some studies suggest that rhodiola may help reduce fatigue, improve mental performance, and boost the immune system, but more research is needed to confirm these effects and determine optimal dosages.

It's important to note that while some supplements containing rhodiola rosea are available over-the-counter, they are not regulated by the Food and Drug Administration (FDA) in the same way as prescription drugs, so it's important to talk to a healthcare provider before taking them. Additionally, rhodiola may interact with certain medications or have side effects, so it's important to use it under the guidance of a healthcare professional.

Cholesterol oxidase is an enzyme that catalyzes the conversion of cholesterol to cholest-4-en-3-one, while reducing molecular oxygen to hydrogen peroxide. This reaction is commonly used in clinical and research settings to measure cholesterol levels in samples of blood or other biological fluids. The enzyme is produced by various bacteria, fungi, and plants, and can be purified for use in diagnostic kits and biochemical assays. In addition to its role in cholesterol analysis, cholesterol oxidase has also been studied as a potential therapeutic agent for the treatment of bacterial infections and cancer.

Sprague-Dawley rats are a strain of albino laboratory rats that are widely used in scientific research. They were first developed by researchers H.H. Sprague and R.C. Dawley in the early 20th century, and have since become one of the most commonly used rat strains in biomedical research due to their relatively large size, ease of handling, and consistent genetic background.

Sprague-Dawley rats are outbred, which means that they are genetically diverse and do not suffer from the same limitations as inbred strains, which can have reduced fertility and increased susceptibility to certain diseases. They are also characterized by their docile nature and low levels of aggression, making them easier to handle and study than some other rat strains.

These rats are used in a wide variety of research areas, including toxicology, pharmacology, nutrition, cancer, and behavioral studies. Because they are genetically diverse, Sprague-Dawley rats can be used to model a range of human diseases and conditions, making them an important tool in the development of new drugs and therapies.

L-amino acid oxidase (LAAO) is an enzyme that belongs to the family of flavin monooxygenases. It catalyzes the oxidative deamination of L-amino acids into corresponding α-keto acids, ammonia, and hydrogen peroxide. The reaction takes place in the presence of molecular oxygen and FAD (flavin adenine dinucleotide) as a cofactor.

LAAO is found in various organisms, including mammals, reptiles, fish, insects, bacteria, and plants. In some species, LAAO plays a role in the metabolism of amino acids, while in others, it functions as a part of the immune system or contributes to the development of venoms and toxins.

In humans, LAAO is primarily located in the peroxisomes of liver, kidney, and intestinal cells, where it participates in the catabolism of amino acids. In addition, LAAO has been found to have potential roles in several pathological conditions, such as neurodegenerative disorders, atherosclerosis, and cancer, due to its ability to generate hydrogen peroxide and induce oxidative stress.

Pyruvate oxidase is not a term that has a widely recognized medical definition. However, pyruvate oxidase is an enzyme that plays a role in the metabolism of glucose in cells. It is involved in the conversion of pyruvate, a product of glycolysis, into acetyl-CoA, which can then be used in the citric acid cycle (also known as the Krebs cycle) to generate energy in the form of ATP.

Pyruvate oxidase is found in the mitochondria of cells and requires molecular oxygen (O2) to function. It catalyzes the following reaction:

pyruvate + CoA + NAD+ + H2O → acetyl-CoA + CO2 + NADH + H+

Deficiencies in pyruvate oxidase have been associated with certain metabolic disorders, such as pyruvate dehydrogenase deficiency and Leigh syndrome. However, these conditions are typically caused by defects in other enzymes involved in the metabolism of pyruvate rather than pyruvate oxidase itself.

The endothelium is a thin layer of simple squamous epithelial cells that lines the interior surface of blood vessels, lymphatic vessels, and heart chambers. The vascular endothelium, specifically, refers to the endothelial cells that line the blood vessels. These cells play a crucial role in maintaining vascular homeostasis by regulating vasomotor tone, coagulation, platelet activation, inflammation, and permeability of the vessel wall. They also contribute to the growth and repair of the vascular system and are involved in various pathological processes such as atherosclerosis, hypertension, and diabetes.

Luminescent measurements refer to the quantitative assessment of the emission of light from a substance that has been excited, typically through some form of energy input such as electrical energy or radiation. In the context of medical diagnostics and research, luminescent measurements can be used in various applications, including bioluminescence imaging, which is used to study biological processes at the cellular and molecular level.

Bioluminescence occurs when a chemical reaction produces light within a living organism, often through the action of enzymes such as luciferase. By introducing a luciferase gene into cells or organisms, researchers can use bioluminescent measurements to track cellular processes and monitor gene expression in real time.

Luminescent measurements may also be used in medical research to study the properties of materials used in medical devices, such as LEDs or optical fibers, or to develop new diagnostic tools based on light-emitting nanoparticles or other luminescent materials.

In summary, luminescent measurements are a valuable tool in medical research and diagnostics, providing a non-invasive way to study biological processes and develop new technologies for disease detection and treatment.

In the context of medicine, iron is an essential micromineral and key component of various proteins and enzymes. It plays a crucial role in oxygen transport, DNA synthesis, and energy production within the body. Iron exists in two main forms: heme and non-heme. Heme iron is derived from hemoglobin and myoglobin in animal products, while non-heme iron comes from plant sources and supplements.

The recommended daily allowance (RDA) for iron varies depending on age, sex, and life stage:

* For men aged 19-50 years, the RDA is 8 mg/day
* For women aged 19-50 years, the RDA is 18 mg/day
* During pregnancy, the RDA increases to 27 mg/day
* During lactation, the RDA for breastfeeding mothers is 9 mg/day

Iron deficiency can lead to anemia, characterized by fatigue, weakness, and shortness of breath. Excessive iron intake may result in iron overload, causing damage to organs such as the liver and heart. Balanced iron levels are essential for maintaining optimal health.

Hydrogen-ion concentration, also known as pH, is a measure of the acidity or basicity of a solution. It is defined as the negative logarithm (to the base 10) of the hydrogen ion activity in a solution. The standard unit of measurement is the pH unit. A pH of 7 is neutral, less than 7 is acidic, and greater than 7 is basic.

In medical terms, hydrogen-ion concentration is important for maintaining homeostasis within the body. For example, in the stomach, a high hydrogen-ion concentration (low pH) is necessary for the digestion of food. However, in other parts of the body such as blood, a high hydrogen-ion concentration can be harmful and lead to acidosis. Conversely, a low hydrogen-ion concentration (high pH) in the blood can lead to alkalosis. Both acidosis and alkalosis can have serious consequences on various organ systems if not corrected.

Oxidoreductases acting on sulfur group donors are a class of enzymes that catalyze redox reactions involving sulfur group donors. These enzymes play a crucial role in various biological processes, such as the metabolism of sulfur-containing compounds and the detoxification of xenobiotics.

The term "oxidoreductase" refers to any enzyme that catalyzes an oxidation-reduction reaction, where one molecule is oxidized (loses electrons) and another is reduced (gains electrons). In the case of oxidoreductases acting on sulfur group donors, the sulfur atom in the substrate serves as the electron donor.

The systematic name for this class of enzymes follows a specific format: "donor:acceptor oxidoreductase." The donor is the sulfur-containing compound that donates electrons, and the acceptor is the molecule that accepts the electrons. For example, the enzyme that catalyzes the reaction between glutathione (GSH) and a variety of electrophiles is called glutathione transferase, or GST (donor:acceptor oxidoreductase).

These enzymes are further classified into subclasses based on the type of acceptor involved in the reaction. Examples include:

* EC 1.8.1: Oxidoreductases acting on CH-NH2 group donors
* EC 1.8.3: Oxidoreductases acting on CH or CH2 groups
* EC 1.8.4: Oxidoreductases acting on the CH-CH group of donors
* EC 1.8.5: Oxidoreductases acting on a sulfur group of donors
* EC 1.8.6: Oxidoreductases acting on NADH or NADPH

The subclass EC 1.8.5, oxidoreductases acting on a sulfur group of donors, includes enzymes that catalyze redox reactions involving sulfur-containing compounds such as thiols (compounds containing -SH groups), disulfides (-S-S- bonds), and other sulfur-containing functional groups. These enzymes play crucial roles in various biological processes, including detoxification, antioxidant defense, and redox regulation.

Peroxidase is a type of enzyme that catalyzes the chemical reaction in which hydrogen peroxide (H2O2) is broken down into water (H2O) and oxygen (O2). This enzymatic reaction also involves the oxidation of various organic and inorganic compounds, which can serve as electron donors.

Peroxidases are widely distributed in nature and can be found in various organisms, including bacteria, fungi, plants, and animals. They play important roles in various biological processes, such as defense against oxidative stress, breakdown of toxic substances, and participation in metabolic pathways.

The peroxidase-catalyzed reaction can be represented by the following chemical equation:

H2O2 + 2e- + 2H+ → 2H2O

In this reaction, hydrogen peroxide is reduced to water, and the electron donor is oxidized. The peroxidase enzyme facilitates the transfer of electrons between the substrate (hydrogen peroxide) and the electron donor, making the reaction more efficient and specific.

Peroxidases have various applications in medicine, industry, and research. For example, they can be used for diagnostic purposes, as biosensors, and in the treatment of wastewater and medical wastes. Additionally, peroxidases are involved in several pathological conditions, such as inflammation, cancer, and neurodegenerative diseases, making them potential targets for therapeutic interventions.

I'm sorry for any confusion, but "Ditiocarb" is not a recognized medical term or abbreviation in standard medical or clinical contexts. It's possible that you may have made a typo or are referring to a term from a different field. If you have more information or if there's a specific context in which you encountered this term, I'd be happy to help further!

Sulfur is not typically referred to in the context of a medical definition, as it is an element found in nature and not a specific medical condition or concept. However, sulfur does have some relevance to certain medical topics:

* Sulfur is an essential element that is a component of several amino acids (the building blocks of proteins) and is necessary for the proper functioning of enzymes and other biological processes in the body.
* Sulfur-containing compounds, such as glutathione, play important roles in antioxidant defense and detoxification in the body.
* Some medications and supplements contain sulfur or sulfur-containing compounds, such as dimethyl sulfoxide (DMSO), which is used topically for pain relief and inflammation.
* Sulfur baths and other forms of sulfur-based therapies have been used historically in alternative medicine to treat various conditions, although their effectiveness is not well-established by scientific research.

It's important to note that while sulfur itself is not a medical term, it can be relevant to certain medical topics and should be discussed with a healthcare professional if you have any questions or concerns about its use in medications, supplements, or therapies.

Sulfite oxidase is a medical term that refers to an enzyme found in the human body, primarily in the liver and brain. This enzyme plays a crucial role in the metabolism of sulfur-containing amino acids, such as methionine and cysteine.

Sulfite oxidase catalyzes the conversion of sulfites to sulfates, which is an essential step in the detoxification of sulfur-containing compounds. The enzyme requires molybdenum and heme cofactors for its activity. A deficiency in this enzyme can lead to a rare genetic disorder known as sulfite oxidase deficiency, which is characterized by developmental delay, seizures, and severe neurological symptoms.

Pancreatin is a mixture of digestive enzymes, including amylase, lipase, and proteases, naturally produced by the pancreas in humans and other mammals. These enzymes aid in the digestion of carbohydrates, fats, and proteins, respectively, in the small intestine. Pancreatin is often used as a replacement therapy for individuals with conditions like cystic fibrosis, chronic pancreatitis, or pancreatectomy, who have impaired pancreatic function and struggle to digest food properly. It can be obtained from animal pancreases, typically from pigs, and is available in various forms such as tablets, capsules, or powders for medical use.

2,6-Dichloroindophenol is a chemical compound that is used as an indicator in various analytical procedures, particularly in the field of biochemistry and microbiology. It is a derivative of indophenol, which contains two chlorine atoms at the 2nd and 6th positions of the benzene ring.

The chemical formula for 2,6-Dichloroindophenol is C8H6Cl2O2. This compound is a deep blue color in its oxidized state and turns colorless when reduced. The reduction potential of this compound makes it useful as an indicator in various redox reactions, including the determination of the concentration of reducing agents such as ascorbic acid (vitamin C) and other antioxidants.

It is important to note that 2,6-Dichloroindophenol is a hazardous chemical and should be handled with care. It can cause skin and eye irritation, and prolonged exposure may lead to more serious health effects. Therefore, it is essential to follow proper safety precautions when working with this compound.

Copper is a chemical element with the symbol Cu (from Latin: *cuprum*) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. Copper is found as a free element in nature, and it is also a constituent of many minerals such as chalcopyrite and bornite.

In the human body, copper is an essential trace element that plays a role in various physiological processes, including iron metabolism, energy production, antioxidant defense, and connective tissue synthesis. Copper is found in a variety of foods, such as shellfish, nuts, seeds, whole grains, and organ meats. The recommended daily intake of copper for adults is 900 micrograms (mcg) per day.

Copper deficiency can lead to anemia, neutropenia, impaired immune function, and abnormal bone development. Copper toxicity, on the other hand, can cause nausea, vomiting, abdominal pain, diarrhea, and in severe cases, liver damage and neurological symptoms. Therefore, it is important to maintain a balanced copper intake through diet and supplements if necessary.

The Electron Transport Chain (ETC) is a series of complexes in the inner mitochondrial membrane that are involved in the process of cellular respiration. It is the final pathway for electrons derived from the oxidation of nutrients such as glucose, fatty acids, and amino acids to be transferred to molecular oxygen. This transfer of electrons drives the generation of a proton gradient across the inner mitochondrial membrane, which is then used by ATP synthase to produce ATP, the main energy currency of the cell.

The electron transport chain consists of four complexes (I-IV) and two mobile electron carriers (ubiquinone and cytochrome c). Electrons from NADH and FADH2 are transferred to Complex I and Complex II respectively, which then pass them along to ubiquinone. Ubiquinone then transfers the electrons to Complex III, which passes them on to cytochrome c. Finally, cytochrome c transfers the electrons to Complex IV, where they combine with oxygen and protons to form water.

The transfer of electrons through the ETC is accompanied by the pumping of protons from the mitochondrial matrix to the intermembrane space, creating a proton gradient. The flow of protons back across the inner membrane through ATP synthase drives the synthesis of ATP from ADP and inorganic phosphate.

Overall, the electron transport chain is a crucial process for generating energy in the form of ATP in the cell, and it plays a key role in many metabolic pathways.

Catechol oxidase, also known as polyphenol oxidase, is an enzyme that catalyzes the oxidation of catechols and other phenolic compounds to quinones. These quinones can then undergo further reactions to form various pigmented compounds, such as melanins. Catechol oxidase is widely distributed in nature and is found in plants, fungi, and some bacteria. In humans, catechol oxidase is involved in the metabolism of neurotransmitters such as dopamine and epinephrine.

"Spin labels" are a term used in the field of magnetic resonance, including nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR). They refer to molecules or atoms that have been chemically attached to a system of interest and possess a stable, unpaired electron. This unpaired electron behaves like a tiny magnet and can be manipulated using magnetic fields and radiofrequency pulses in EPR experiments. The resulting changes in the electron's spin state can provide information about the local environment, dynamics, and structure of the system to which it is attached. Spin labels are often used in biochemistry and materials science to study complex biological systems or materials at the molecular level.

Protoporphyrinogen Oxidase (PPO) is a mitochondrial enzyme that plays a crucial role in the heme biosynthesis pathway. It catalyzes the oxidation of protoporphyrinogen IX to protporphyrin IX, which is the penultimate step in the production of heme. This enzyme is the target of certain herbicides, such as those containing the active ingredient diphenyl ether, and genetic deficiencies in PPO can lead to a rare genetic disorder called Protoporphyria.

Guanine Deaminase is an enzyme that catalyzes the chemical reaction in which guanine, one of the four nucleotides that make up DNA and RNA, is deaminated to form xanthine. This reaction is part of the purine catabolism pathway, which is the breakdown of purines to produce energy and eliminate nitrogenous waste. The gene that encodes this enzyme in humans is located on chromosome 2 and is called GDA. Deficiency in guanine deaminase has been associated with Lesch-Nyhan syndrome, a rare genetic disorder characterized by mental retardation, self-mutilation, spasticity, and uric acid overproduction.

Glutathione is a tripeptide composed of three amino acids: cysteine, glutamic acid, and glycine. It is a vital antioxidant that plays an essential role in maintaining cellular health and function. Glutathione helps protect cells from oxidative stress by neutralizing free radicals, which are unstable molecules that can damage cells and contribute to aging and diseases such as cancer, heart disease, and dementia. It also supports the immune system, detoxifies harmful substances, and regulates various cellular processes, including DNA synthesis and repair.

Glutathione is found in every cell of the body, with particularly high concentrations in the liver, lungs, and eyes. The body can produce its own glutathione, but levels may decline with age, illness, or exposure to toxins. As such, maintaining optimal glutathione levels through diet, supplementation, or other means is essential for overall health and well-being.

Reperfusion injury is a complex pathophysiological process that occurs when blood flow is restored to previously ischemic tissues, leading to further tissue damage. This phenomenon can occur in various clinical settings such as myocardial infarction (heart attack), stroke, or peripheral artery disease after an intervention aimed at restoring perfusion.

The restoration of blood flow leads to the generation of reactive oxygen species (ROS) and inflammatory mediators, which can cause oxidative stress, cellular damage, and activation of the immune system. This results in a cascade of events that may lead to microvascular dysfunction, capillary leakage, and tissue edema, further exacerbating the injury.

Reperfusion injury is an important consideration in the management of ischemic events, as interventions aimed at restoring blood flow must be carefully balanced with potential harm from reperfusion injury. Strategies to mitigate reperfusion injury include ischemic preconditioning (exposing the tissue to short periods of ischemia before a prolonged ischemic event), ischemic postconditioning (applying brief periods of ischemia and reperfusion after restoring blood flow), remote ischemic preconditioning (ischemia applied to a distant organ or tissue to protect the target organ), and pharmacological interventions that scavenge ROS, reduce inflammation, or improve microvascular function.

Malondialdehyde (MDA) is a naturally occurring organic compound that is formed as a byproduct of lipid peroxidation, a process in which free radicals or reactive oxygen species react with polyunsaturated fatty acids. MDA is a highly reactive aldehyde that can modify proteins, DNA, and other biomolecules, leading to cellular damage and dysfunction. It is often used as a marker of oxidative stress in biological systems and has been implicated in the development of various diseases, including cancer, cardiovascular disease, and neurodegenerative disorders.

In the context of medicine, "chemistry" often refers to the field of study concerned with the properties, composition, and structure of elements and compounds, as well as their reactions with one another. It is a fundamental science that underlies much of modern medicine, including pharmacology (the study of drugs), toxicology (the study of poisons), and biochemistry (the study of the chemical processes that occur within living organisms).

In addition to its role as a basic science, chemistry is also used in medical testing and diagnosis. For example, clinical chemistry involves the analysis of bodily fluids such as blood and urine to detect and measure various substances, such as glucose, cholesterol, and electrolytes, that can provide important information about a person's health status.

Overall, chemistry plays a critical role in understanding the mechanisms of diseases, developing new treatments, and improving diagnostic tests and techniques.

Cyanides are a group of chemical compounds that contain the cyano group, -CN, which consists of a carbon atom triple-bonded to a nitrogen atom. They are highly toxic and can cause rapid death due to the inhibition of cellular respiration. Cyanide ions (CN-) bind to the ferric iron in cytochrome c oxidase, a crucial enzyme in the electron transport chain, preventing the flow of electrons and the production of ATP, leading to cellular asphyxiation.

Common sources of cyanides include industrial chemicals such as hydrogen cyanide (HCN) and potassium cyanide (KCN), as well as natural sources like certain fruits, nuts, and plants. Exposure to high levels of cyanides can occur through inhalation, ingestion, or skin absorption, leading to symptoms such as headache, dizziness, nausea, vomiting, rapid heartbeat, seizures, coma, and ultimately death. Treatment for cyanide poisoning typically involves the use of antidotes that bind to cyanide ions and convert them into less toxic forms, such as thiosulfate and rhodanese.

"Cells, cultured" is a medical term that refers to cells that have been removed from an organism and grown in controlled laboratory conditions outside of the body. This process is called cell culture and it allows scientists to study cells in a more controlled and accessible environment than they would have inside the body. Cultured cells can be derived from a variety of sources, including tissues, organs, or fluids from humans, animals, or cell lines that have been previously established in the laboratory.

Cell culture involves several steps, including isolation of the cells from the tissue, purification and characterization of the cells, and maintenance of the cells in appropriate growth conditions. The cells are typically grown in specialized media that contain nutrients, growth factors, and other components necessary for their survival and proliferation. Cultured cells can be used for a variety of purposes, including basic research, drug development and testing, and production of biological products such as vaccines and gene therapies.

It is important to note that cultured cells may behave differently than they do in the body, and results obtained from cell culture studies may not always translate directly to human physiology or disease. Therefore, it is essential to validate findings from cell culture experiments using additional models and ultimately in clinical trials involving human subjects.

A dose-response relationship in the context of drugs refers to the changes in the effects or symptoms that occur as the dose of a drug is increased or decreased. Generally, as the dose of a drug is increased, the severity or intensity of its effects also increases. Conversely, as the dose is decreased, the effects of the drug become less severe or may disappear altogether.

The dose-response relationship is an important concept in pharmacology and toxicology because it helps to establish the safe and effective dosage range for a drug. By understanding how changes in the dose of a drug affect its therapeutic and adverse effects, healthcare providers can optimize treatment plans for their patients while minimizing the risk of harm.

The dose-response relationship is typically depicted as a curve that shows the relationship between the dose of a drug and its effect. The shape of the curve may vary depending on the drug and the specific effect being measured. Some drugs may have a steep dose-response curve, meaning that small changes in the dose can result in large differences in the effect. Other drugs may have a more gradual dose-response curve, where larger changes in the dose are needed to produce significant effects.

In addition to helping establish safe and effective dosages, the dose-response relationship is also used to evaluate the potential therapeutic benefits and risks of new drugs during clinical trials. By systematically testing different doses of a drug in controlled studies, researchers can identify the optimal dosage range for the drug and assess its safety and efficacy.

Sarcosine oxidase is an enzyme that plays a role in the metabolism of certain amino acids. Specifically, it catalyzes the oxidation of sarcosine (also known as N-methylglycine) to form glycine, formaldehyde, and hydrogen peroxide. This reaction is an important step in the catabolism of certain amino acids, such as glycine, sarcosine, and betaine, and helps to generate energy for the cell.

Sarcosine oxidase is a complex enzyme that consists of two subunits: a catalytic subunit that contains the active site where the chemical reaction takes place, and a regulatory subunit that helps to control the activity of the enzyme. The enzyme requires several cofactors, including molybdenum, iron, and flavin adenine dinucleotide (FAD), in order to function properly.

Deficiencies or mutations in sarcosine oxidase can lead to various metabolic disorders, such as glycine encephalopathy (also known as non-ketotic hyperglycinemia), which is characterized by an accumulation of glycine in the body and can cause neurological symptoms.

Chemical phenomena refer to the changes and interactions that occur at the molecular or atomic level when chemicals are involved. These phenomena can include chemical reactions, in which one or more substances (reactants) are converted into different substances (products), as well as physical properties that change as a result of chemical interactions, such as color, state of matter, and solubility. Chemical phenomena can be studied through various scientific disciplines, including chemistry, biochemistry, and physics.

... explaining why xanthine oxidase is being researched for links to cardiovascular health. Both xanthine oxidase and xanthine ... Because xanthine oxidase is a metabolic pathway for uric acid formation, the xanthine oxidase inhibitor allopurinol is used in ... The following chemical reactions are catalyzed by xanthine oxidase: hypoxanthine + H2O + O2 ⇌ xanthine + H2O2 xanthine + H2O + ... "Inhibitory effects of flavonoids on xanthine oxidase". Anticancer Research. 13 (6A): 2165-70. PMID 8297130. Xanthine+Oxidase at ...
A xanthine oxidase inhibitor is any substance that inhibits the activity of xanthine oxidase, an enzyme involved in purine ... Xanthine oxidase inhibitors are being investigated for management of reperfusion injury. Xanthine oxidase inhibitors are of two ... inhibition of xanthine oxidase reduces the production of uric acid, and several medications that inhibit xanthine oxidase are ... is only a weak inhibitor of xanthine oxidase. Pacher P, Nivorozhkin A, Szabó C (March 2006). "Therapeutic Effects of Xanthine ...
See Xanthine oxidase. Volodymyr Vernadsky (1863-1945), mineralogist and geochemist, founder and first chairman of the Ukrainian ...
He investigated xanthine oxidase, and thereby elucidated many aspects of the chemistry of dehydrogenases. He showed that the ... Dixon, M.; Keilin, D. (1936). "The action of cyanide and other respiratory inhibitors on xanthine oxidase". Proceedings of the ... Dixon, Malcolm (1925). "Studies on Xanthine Oxidase". Biochemical Journal. 19 (3): 507-512. doi:10.1042/bj0190507. PMC 1259209 ... Dixon published a series of papers on D-amino acid oxidase, detailing the kinetics and thermodynamics of association of the ...
Xanthine oxidase Gennaro, M. C.; Abrigo, C. (1992). "Caffeine and theobromine in coffee, tea and cola-beverages or any other ... Theobromine poisoning, also informally called chocolate poisoning or cocoa poisoning, is an overdosage reaction to the xanthine ...
Mastitic milk generally has lower SNF (solid-not-fat). Xanthine oxidase reduces by nearly half. Cattle affected by mastitis can ...
Aldehyde oxidase and xanthine dehydrogenase, a/b hammerhead domain MOCOS Xanthine oxidase GRCh38: Ensembl release 89: ... xanthine-NAD+ oxidoreductase, xanthine/NAD+ oxidoreductase, and xanthine oxidoreductase. Defects in xanthine dehydrogenase ... Xanthine dehydrogenase can be converted to xanthine oxidase by reversible sulfhydryl oxidation or by irreversible proteolytic ... Cejková J, Ardan T, Filipec M, Midelfart A (2003). "Xanthine oxidoreductase and xanthine oxidase in human cornea". Histology ...
Olson, J S; Ballou, D P; Palmer, G; Massey, V (1974). "Reaction of xanthine-oxidase with molecular-oxygen". J. Biol. Chem. 249 ... Palmer, G; Massey, V (1969). "Electron paramagnetic resonance and circular dichroism studies on milk xanthine oxidase". J. Biol ... "Direct expression of active spinach glycolate oxidase in Escherichia coli". Biochimica et Biophysica Acta (BBA) - Gene ...
Alloxanthine is an inhibitor of xanthine oxidase. It is also an isostere of xanthine, the normal substrate for the enzyme. ...
"Xanthine oxidase inhibitors from Archidendron clypearia (Jack.) I.C. Nielsen: Results from systematic screening of Vietnamese ...
Role of acetaldehyde/xanthine oxidase-generated superoxide". Biochemical Journal. 257 (1): 277-280. doi:10.1042/bj2570277. ISSN ...
Blauch M, Koch FC, Hane ME (1939). "A study of xanthine oxidase of rat blood". J. Biol. Chem. 130: 471-486. Heppel LA, Hurwitz ...
Xanthine oxidase (XO): XO, under normal circumstances, is an important enzyme in producing uric acid, released from the kidneys ... Kostić DA, Dimitrijević DS, Stojanović GS, Palić IR, Đorđević AS, Ickovski JD (February 2015). "Xanthine Oxidase: Isolation, ... NADH/NADPH oxidase: These enzymes contribute significantly to the amount of ROS present in the body. If in cardiac distress, an ... "NADPH Oxidase - an overview , ScienceDirect Topics". www.sciencedirect.com. Retrieved 2022-04-06. ...
... leaves extract and xanthine oxidase inhibitory study" (PDF). International Journal of Pharmacy and Pharmaceutical Sciences. 2 ( ...
Xanthine oxidase will degrade hypoxanthine to xanthine and then to uric acid. Xanthine is not very soluble in water; therefore ... an increase in xanthine forms crystals (which can lead to kidney stones) and result in damage to the kidney. Xanthine oxidase ... Another possible cause of Kidney disease is due to decreased function of xanthine oxidase in the purine degradation pathway. ... xanthine oxidase deficiency, toxicity of chemotherapy agents, and a long-term exposure to lead or its salts. Chronic conditions ...
Hajj, S.; Nasrallah, S. M.; Shaamma, M. H.; Al-Khalidi, U. (1967). "Serum Xanthine Oxidase in Normal and Abnormal Pregnancy". ... "Serum Xanthine Oxidase: A Sensitive Test of Acute Liver Injury". Gastroenterology. 48 (2): 226-230. doi:10.1016/S0016-5085(65) ...
Pick FM, McGartoll MA, Bray RC (January 1971). "Reaction of formaldehyde and of methanol with xanthine oxidase". European ...
By inhibiting xanthine oxidase, it reduces uric acid production. High serum uric acid levels may result in gout, kidney stones ... Oxipurinol (INN, or oxypurinol USAN) is an inhibitor of xanthine oxidase. It is an active metabolite of allopurinol and it is ... Xanthine oxidase inhibitors, Human drug metabolites, All stub articles, Heterocyclic compound stubs). ...
... which is the active site of xanthine oxidase. Xanthine oxidase is needed to oxidize successively hypoxanthine and xanthine to ... It inhibits xanthine oxidase, thus reducing production of uric acid in the body. Febuxostat was approved for medical use in the ... Thus, febuxostat inhibits xanthine oxidase, thereby reducing production of uric acid. Febuxostat inhibits both the oxidized and ... Febuxostat is a non-purine-selective inhibitor of xanthine oxidase. It works by non-competitively blocking the molybdenum ...
It inhibited xanthine oxidase as potently as allopurinol (IC50 = 0.65 μM). Catharanthine Pericine Tabernaemontanine Herbert ... "Alkaloids isolated from Tabernaemontana bufalina display xanthine oxidase inhibitory activity". Phytochemistry. 166: 112060. ...
... inhibition of xanthine oxidase causes an increase in hypoxanthine and xanthine. While xanthine cannot be converted to purine ... and is an inhibitor of the enzyme xanthine oxidase. Xanthine oxidase is responsible for the successive oxidation of ... xanthine oxidase, but this action is principally carried out by aldehyde oxidase. The active metabolite of allopurinol is ... "Demonstration of a combined deficiency of xanthine oxidase and aldehyde oxidase in xanthinuric patients not forming oxipurinol ...
Those enzymes include aldehyde oxidase, sulfite oxidase and xanthine oxidase. With one exception, Mo in proteins is bound by ... is catalyzed by xanthine oxidase, a molybdenum-containing enzyme. The activity of xanthine oxidase is directly proportional to ... sulfite oxidase, xanthine oxidoreductase, aldehyde oxidase, and mitochondrial amidoxime reductase. People severely deficient in ... The Relationship between Sulfite Oxidase and the Acute Toxicity of Bisulfite and SO2". Proceedings of the National Academy of ...
Palmour RM, Goodyer P, Reade T, Chang TM (September 1989). "Microencapsulated xanthine oxidase as experimental therapy in Lesch ...
Those enzymes include aldehyde oxidase, sulfite oxidase and xanthine oxidase. With one exception, Mo in proteins is bound by ... is catalyzed by xanthine oxidase, a molybdenum-containing enzyme. The activity of xanthine oxidase is directly proportional to ... sulfite oxidase, xanthine oxidoreductase, aldehyde oxidase, and mitochondrial amidoxime reductase. People severely deficient in ... The Relationship between Sulfite Oxidase and the Acute Toxicity of Bisulfite and SO2". Proceedings of the National Academy of ...
"Influence of xanthine oxidase on thiopurine metabolism in Crohn's disease". Alimentary Pharmacology & Therapeutics. 28 (6): 749 ...
Allopurinol inhibits xanthine oxidase, the enzyme that breaks down mercaptopurine. Those taking allopurinol (often used to ...
... is a xanthine oxidase inhibitor which reduces serum urate levels. "New Drugs FY2013" (PDF). Pharmaceuticals and ... Xanthine oxidase inhibitors, Triazoles, Pyridines, Nitriles, All stub articles, Musculoskeletal system drug stubs). ...
Type I xanthinuria can be caused by a deficiency of xanthine oxidase, which is an enzyme necessary for converting xanthine to ... Xanthinuria, also known as xanthine oxidase deficiency, is a rare genetic disorder causing the accumulation of xanthine. It is ... Type II xanthinuria and molybdenum cofactor deficiency lack one or two other enzyme activities in addition to xanthine oxidase ... Ichida K, Amaya Y, Kamatani N, Nishino T, Hosoya T, Sakai O (May 1997). "Identification of two mutations in human xanthine ...
The compounds, named squarrosidine and pinillidine, inhibit the enzyme xanthine oxidase. Xanthine oxidase catalyzes the ...
... is a xanthine oxidase inhibitor used for the treatment of gout. O'Regan MH, Smith-Barbour M, Perkins LM, Cao X, ... a xanthine oxidase inhibitor, on ischemia-evoked purine release and free radical formation in the rat cerebral cortex". ... Xanthine oxidase inhibitors, Trifluoromethyl compounds, Isothiazoles, Carboxylic acids, All stub articles, Musculoskeletal ...
... explaining why xanthine oxidase is being researched for links to cardiovascular health. Both xanthine oxidase and xanthine ... Because xanthine oxidase is a metabolic pathway for uric acid formation, the xanthine oxidase inhibitor allopurinol is used in ... The following chemical reactions are catalyzed by xanthine oxidase: hypoxanthine + H2O + O2 ⇌ xanthine + H2O2 xanthine + H2O + ... "Inhibitory effects of flavonoids on xanthine oxidase". Anticancer Research. 13 (6A): 2165-70. PMID 8297130. Xanthine+Oxidase at ...
... a product of xanthine oxidase (XO), may be a useful marker for metabolic, hemodynamic, and functional staging in heart failure ... Uric acid, heart failure survival, and the impact of xanthine oxidase inhibition Congest Heart Fail. 2012 May-Jun;18(3):179-82. ... Increasing evidence suggests that serum uric acid (UA), a product of xanthine oxidase (XO), may be a useful marker for ...
Xanthine Oxidase Inhibitors. Class Summary. Xanthine oxidase inhibitors are effective for treating diuretic-induced ... Allopurinol inhibits xanthine oxidase, the enzyme that synthesizes uric acid from hypoxanthine. It reduces synthesis of uric ...
... of Lesinurad Monotherapy Compared to Placebo in Subjects with Gout and an Intolerance or Contraindication to a Xanthine Oxidase ...
During purification the enzyme is largely converted to the O2-dependent xanthine oxidase form (EC 1.17.3.2). ...
Studies on Xanthine Oxidase: Relation of Xanthine Oxidase and similar Oxidising Systems to Bachs Oxygenase ... Studies on Xanthine Oxidase: The Function of Catalase. scientific article published on January 1925 ...
... is a potent xanthine oxidase (XOD) inhibitor with an IC50 of 31.81 μM. - Mechanism of Action & Protocol. ... Xanthine oxidase-IN-9 (Icarisids E) (Compound 2) is a potent xanthine oxidase (XOD) inhibitor with an IC50 of 31.81 μM[1]. ... Xanthine oxidase-IN-92571069-61-7Icarisids EXanthine OxidaseXOCyclocarya paliurusuric acidhyperuricemiaInhibitorinhibitor ... Xanthine oxidase-IN-9 (Icarisids E) (Compound 2) is a potent xanthine oxidase (XOD) inhibitor with an IC50 of 31.81 μM. ...
Home > Inhibitors/Agonists > Metabolic Enzyme > Xanthine Oxidase Xanthine Oxidase. Structure. Catalog #. Chemical Name. CAS. MF ...
Xanthine oxidase is also recognized as a pivotal enzyme in the production of oxidative stress. Excess oxidative stress induces ... Many experimental studies have suggested that xanthine oxidase inhibitors have anti-atherosclerotic effects by decreasing in ... However, there is only limited evidence on the clinical implications of xanthine oxidase inhibitors on atherosclerotic ... Xanthine oxidase inhibitors are anti-hyperuricemic drugs that decrease serum uric acid levels by inhibiting its synthesis. ...
Xanthine oxidase, enzyme, uric acid. Subjects:. R Medicine , RM Therapeutics. Pharmacology. T Technology , T Technology ( ... Screening and optimization of process conditions for extraction of Xanthine Oxidase Inhibitor from potential local medicinal ... PDF (Screening and optimization of process conditions for extraction of Xanthine Oxidase Inhibitor from potential local ... Screening and optimization of process conditions for extraction of Xanthine Oxidase Inhibitor from potential local medicinal ...
Xanthine oxidase inhibitors. Class Summary. Allopurinol is used for the prevention of acute uric acid nephropathy. By blocking ... Xanthine oxidase inhibitor. Prevents uric acid production and lowers elevated serum uric acid levels. May be considered as an ... Increased xanthine oxidase in the skin of preeclamptic women. Reprod Sci. 2009 Feb 5. [QxMD MEDLINE Link]. ... Inhibits xanthine oxidase, the enzyme that synthesizes uric acid from hypoxanthine. Reduces synthesis of uric acid without ...
Dronov, R., Kurth, D., Mohwald, H., Scheller, F. and Lisdat, F. (2007). A self-assembled cytochrome c/xanthine oxidase ...
Elevation of serum xanthine oxidase following halothane anesthesia in the rat. Sh Giler*, E. Ventura, E. Levy, I. Urca, O. ... Elevation of serum xanthine oxidase following halothane anesthesia in the rat. / Giler, Sh; Ventura, E.; Levy, E. et al. In: ... Elevation of serum xanthine oxidase following halothane anesthesia in the rat. In: Experientia. 1976 ; Vol. 32, No. 5. pp. 620- ... Giler S, Ventura E, Levy E, Urca I, Sperling O, de Vries A. Elevation of serum xanthine oxidase following halothane anesthesia ...
... methods were used to study the full catalytic mechanism of xanthine oxidase (XO). The XO catalyzes the conversion of xanthine ( ... The complete catalytic mechanism of Xanthine Oxidase: a computational study. Pedro MG Ribeiro, Henrique S Fernandes, Luisa B. ... New Collaborative Paper: The complete catalytic mechanism of Xanthine Oxidase: a computational study. Posted on November 4, ... disclosing the complete catalytic mechanism of Xanthine Oxidase. ...
1.17 Xanthine oxidase. *Ribonucleotide reductase. Transferase (EC 2). *2.1 COMT. *Thymidylate synthase ...
... , Clinica Chimica ... Determination of xanthine oxidase in human serum by a competitive enzyme-linked immunosorbent assay (ELISA). ...
1. 1‐methyl xanthine (1‐MX) is metabolized exclusively to 1‐methyl uric acid (1‐MU) by the enzyme xanthine oxidase. 2. The ... N2 - 1. 1‐methyl xanthine (1‐MX) is metabolized exclusively to 1‐methyl uric acid (1‐MU) by the enzyme xanthine oxidase. 2. The ... AB - 1. 1‐methyl xanthine (1‐MX) is metabolized exclusively to 1‐methyl uric acid (1‐MU) by the enzyme xanthine oxidase. 2. The ... abstract = "1. 1‐methyl xanthine (1‐MX) is metabolized exclusively to 1‐methyl uric acid (1‐MU) by the enzyme xanthine oxidase ...
Safety of Xanthine Oxidase Inhibitors (XOIs). The risk for allopurinol hypersensitivity syndrome has caused significant ...
Specific inhibition of xanthine oxidase and cytochrome P-450 revealed, in the two teleosts, that the nitrite-dependent ... Specific inhibition of xanthine oxidase and cytochrome P-450 revealed, in the two teleosts, that the nitrite-dependent ... We also found that xanthine oxidase is more expressed in C. hamatus than in T. bernacchii, while the opposite was observed ... We also found that xanthine oxidase is more expressed in C. hamatus than in T. bernacchii, while the opposite was observed ...
Xanthine dehydrogenase/oxidase. MTADKLVFFVNGRKVVEKNADPETTLLAYLRRKLGLSGTKLGCGEGGCGA.... unknown. inhibitor. Solute carrier ...
The sea plumes of gorgonian extracts was able to inhibit the activity of xanthine oxidase in IC50 of 24.90 μg/mL from bark n- ... THE ACTIVITY OF XANTHINE OXIDASE INHIBITOR AND LIPOXYGENASE INHIBITOR OF SEA PLUMES GORGONIAN RUMPHELLA SP. AND HICKSONELLA SP ... The in vitro result displayed the sea plumes gorgonian extract was less potential as xanthine oxidase and lipoksigenase ... Xanthineoxidase inhibitors analysis from sea plumes of gorgonian extract with measured the uric acid formed of the inhibition ...
Crystal Structure of a Rat Xanthine Dehydrogenase Triple Mutant (C535A, C992R and C1324S) ... Mammalian xanthine dehydrogenase can be converted to xanthine oxidase by modification of cysteine residues or by proteolysis of ... Mammalian xanthine dehydrogenase can be converted to xanthine oxidase by modification of cysteine residues or by proteolysis of ... Mechanism of the Conversion of Xanthine Dehydrogenase to Xanthine Oxidase: IDENTIFICATION OF THE TWO CYSTEINE DISULFIDE BONDS ...
Xanthine oxidase (XO) is an enzyme that catalyzes the metabolism of hypoxanthine and xanthine into uric acid. XO also serves as ... Norlida, Mamat and Jamia Azdina, Jamal and Ibrahim, Jantan (2014) Xanthine oxidase inhibitory and DPPH radical scavenging ... Xanthine oxidase inhibitory and DPPH radical scavenging activities of some primulaceae species ...
Rat XOD (Xanthine Oxidase) ELISA Kit , G-EC-05980 MSRP: Was: Now: $178.56 - $2,665.44 ...
Xanthine dehydrogenase deficiency, see Hereditary xanthinuria. *Xanthine oxidase deficiency, see Hereditary xanthinuria ...
Participation of xanthine-xanthine oxidase system and neutrophils in development of acute gastric mucosal lesions in rats with ... Participation of xanthine-xanthine oxidase system and neutrophils in development of acute gastric mucosal lesions in rats with ... Participation of xanthine-xanthine oxidase system and neutrophils in development of acute gastric mucosal lesions in rats with ... T1 - Participation of xanthine-xanthine oxidase system and neutrophils in development of acute gastric mucosal lesions in rats ...
Among the fractions, 40% and 60% Sep-Pak fraction of MeOH extract had stronger xanthine oxidase inhibitory and antioxidant ... As this plant revealed a high content of phenols along with high antioxidant, antimalarial and xanthine oxidase inhibitory ... The 40% fraction of MeOH extract showed the strongest antioxidant and xanthine oxidase inhibitory activities, which might be ... Among different extracts, MeOH extract had significant antioxidant and xanthine oxidase inhibitory activities with RC50 (mg/mL ...
In vitro xanthine oxidase inhibition assay results also showed that C. verspertilionis aqueous extract display 63.67% ... Phytochemical profiling, in vitro and in vivo xanthine oxidase inhibition and antihyperuricemic activity of Christia ... In vitro xanthine oxidase inhibition assay and oxonate-induced hyperuricemia in rats, which are considered as a hallmark for ... The liver xanthine oxidase activity was also significantly reduced by C. verspertilionis aqueous extract at the same dosage. In ...
Mechanism of free radical production in exhaustive exercise in humans and rats; role of xanthine oxidase and protection by ... role of xanthine oxidase and protection by allopurinol. Together they form a unique fingerprint. ...
IN VITRO INHIBITION OF CELERY ( Apium graveolens L.) EXTRACT ON THE ACTIVITY OF XANTHINE OXIDASE AND DETERMINATION OF ITS ...
  • Because xanthine oxidase is a metabolic pathway for uric acid formation, the xanthine oxidase inhibitor allopurinol is used in the treatment of gout. (wikipedia.org)
  • Xanthine oxidase-IN-9 (Icarisids E) (Compound 2) is a potent xanthine oxidase (XOD) inhibitor with an IC 50 of 31.81 μM. (medchemexpress.com)
  • Xanthine oxidase inhibitor. (medscape.com)
  • The activity of xanthine oxidase inhibitor and lipoxygenase inhibitor of sea plumes gorgonian rumphella sp. (envirobiotechjournals.com)
  • The aim of this study was to verify the activity of the sea plumes gorgonian extract as xanthineoxidase and lipoxygenase inhibitor useful as availability of drugs for pharmacy. (envirobiotechjournals.com)
  • The in vitro result displayed the sea plumes gorgonian extract was less potential as xanthine oxidase and lipoksigenase inhibitor. (envirobiotechjournals.com)
  • The formation of gastric mucosal lesions at 0.5 hr after compound 48/80 injection was prevented by pretreatment with anti-neutrophil antiserum and NPC 14686, an antiinflammatory agent, but not with allopurinol, a xanthine oxidase inhibitor. (fujita-hu.ac.jp)
  • In this study, we aimed to investigate the effects of febuxostat, a novel inhibitor of xanthine oxidase (XO), on renal damage in streptozotocin- (STZ-) induced diabetic rats. (hindawi.com)
  • Febuxostat (Fx) is a recently developed xanthine oxidase (XO) inhibitor, which has been definitively proved to be effective and safe for gout treatment [ 7 ]. (hindawi.com)
  • No Reduction in WMH Progression With Allopurinol After Stroke Use of allopurinol, a xanthine oxidase inhibitor, did not reduce progression of white matter hyperintensity (WMH) after stroke in a randomized trial. (medscape.com)
  • Since xanthine oxidase is involved in the metabolism of 6-mercaptopurine, caution should be taken before administering allopurinol and 6-mercaptopurine, or its prodrug azathioprine, in conjunction. (wikipedia.org)
  • Type II xanthinuria may result from a failure of the mechanism which inserts sulfur into the active sites of xanthine oxidase and aldehyde oxidase, a related enzyme with some overlapping activities (such as conversion of allopurinol to oxypurinol). (wikipedia.org)
  • Relationship between plasma oxipurinol concentrations and xanthine oxidase activity in volunteers dosed with allopurinol. (edu.au)
  • 2. The ratio of 1‐MU to 1‐ MX in the urine, following a dose of 50 mg of 1‐MX infused intravenously over 20 min, was used to measure the inhibition of xanthine oxidase induced by different doses of allopurinol. (edu.au)
  • The increases in gastric mucosal myeloperoxidase activity and lipid peroxide content at 0.5 hr after compound 48/80 injection were attenuated by pretreatment with anti- neutrophil antiserum and NPC 14686, while only the increase in gastric mucosal xanthine oxidase activity at the same time point was arrested by allopurinol pretreatment. (fujita-hu.ac.jp)
  • The increases in gastric mucosal xanthine oxidase and myeloperoxidase activities and lipid peroxide content at 3 hr after compound 48/80 treatment were attenuated by pretreatment with anti-neutrophil antiserum, NPC 14686, or allopurinol. (fujita-hu.ac.jp)
  • When compound 48/80-injected rats were treated with allopurinol at 0.5 hr after compound 48/80 injection, the progression of gastric mucosal lesions at 3 hr after the injection was almost completely prevented with inhibition of the increases in gastric mucosal xanthine oxidase and myeloperoxidase activities and lipid peroxide content. (fujita-hu.ac.jp)
  • Xanthine oxidase inhibitors are anti-hyperuricemic drugs that decrease serum uric acid levels by inhibiting its synthesis. (biomedcentral.com)
  • Many experimental studies have suggested that xanthine oxidase inhibitors have anti-atherosclerotic effects by decreasing in vitro and in vivo oxidative stress. (biomedcentral.com)
  • However, there is only limited evidence on the clinical implications of xanthine oxidase inhibitors on atherosclerotic cardiovascular disease in patients with hyperuricemia. (biomedcentral.com)
  • The same protein, which in humans has the HGNC approved gene symbol XDH, can also have xanthine dehydrogenase activity (EC 1.17.1.4). (wikipedia.org)
  • Most of the protein in the liver exists in a form with xanthine dehydrogenase activity, but it can be converted to xanthine oxidase by reversible sulfhydryl oxidation or by irreversible proteolytic modification. (wikipedia.org)
  • Mammalian xanthine dehydrogenase can be converted to xanthine oxidase by modification of cysteine residues or by proteolysis of the enzyme polypeptide chain. (rcsb.org)
  • Studies have shown that xanthine dehydrogenase (XDH)-derived reactive oxygen species (ROS) accelerates tumor growth, and also induces mutations or produces cytotoxic effects concurrently. (medsci.org)
  • Bovine xanthine oxidase (from milk) was originally thought to have a binding site to reduce cytochrome c with, but it has been found that the mechanism to reduce this protein is through XO's superoxide anion byproduct, with competitive inhibition by carbonic anhydrase. (wikipedia.org)
  • Inhibition of xanthine oxidase has been proposed as a mechanism for improving cardiovascular health. (wikipedia.org)
  • Inhibition of xanthine oxidase was assessed twice, on the last 2 days of each treatment week. (edu.au)
  • Specific inhibition of xanthine oxidase and cytochrome P-450 revealed, in the two teleosts, that the nitrite-dependent inotropism required the nitrite reductase activity of both enzymes. (unical.it)
  • The current project was designed to determine the phytochemical profiling, in vitro and in vivo xanthine inhibition and antihyperuricemic activity of Christia vespertilionis leaf aqueous infusion (to mimic human consumption). (uthm.edu.my)
  • Profiling of phytochemical was done by liquid chromatography-mass spectrometry (LC-MS). In vitro xanthine oxidase inhibition assay and oxonate-induced hyperuricemia in rats, which are considered as a hallmark for promising antihyperuricemic agents were also conducted. (uthm.edu.my)
  • In vitro xanthine oxidase inhibition assay results also showed that C. verspertilionis aqueous extract display 63.67% inhibition at 100 μg/mL with IC50 value of 61.37 μg/mL. (uthm.edu.my)
  • Xanthine oxidase (XO, sometimes 'XAO') is a form of xanthine oxidoreductase, a type of enzyme that generates reactive oxygen species. (wikipedia.org)
  • Xanthine oxidase is defined as an enzyme activity (EC 1.17.3.2). (wikipedia.org)
  • hypoxanthine (one oxygen atom) xanthine (two oxygens) uric acid (three oxygens) Because XO is a superoxide-producing enzyme, with general low specificity, it can be combined with other compounds and enzymes and create reactive oxidants, as well as oxidize other substrates. (wikipedia.org)
  • Xanthine oxidase is a superoxide-producing enzyme found normally in serum and the lungs, and its activity is increased during influenza A infection. (wikipedia.org)
  • During purification the enzyme is largely converted to the O2-dependent xanthine oxidase form (EC 1.17.3.2 ). (expasy.org)
  • Xanthine oxidase is also recognized as a pivotal enzyme in the production of oxidative stress. (biomedcentral.com)
  • Inhibits xanthine oxidase, the enzyme that synthesizes uric acid from hypoxanthine. (medscape.com)
  • 1. 1‐methyl xanthine (1‐MX) is metabolized exclusively to 1‐methyl uric acid (1‐MU) by the enzyme xanthine oxidase. (edu.au)
  • The purified mutants C535A and/or C992R were significantly resistant to conversion by incubation with 4,4'-dithiodipyridine, whereas the recombinant wild-type enzyme converted readily to the oxidase type, indicating that these residues are responsible for the rapid conversion. (rcsb.org)
  • Xanthine oxidase (XO) is an enzyme that catalyzes the metabolism of hypoxanthine and xanthine into uric acid. (unisza.edu.my)
  • XO is an enzyme that generates ROS by catalyzing the oxidation of hypoxanthine to xanthine and xanthine to uric acid. (hindawi.com)
  • It was chosen for study with the aim of screening biologically active compounds in the essential oil of the aerial parts and the antioxidant, antimalarial and xanthine oxidase inhibitory activities of its extract. (springeropen.com)
  • Among different extracts, MeOH extract had significant antioxidant and xanthine oxidase inhibitory activities with RC 50 (mg/mL) = 0.0707 and IC 50 = 12.8741 µg/mL, respectively. (springeropen.com)
  • The 40% fraction of MeOH extract showed the strongest antioxidant and xanthine oxidase inhibitory activities, which might be related to the presence of phenolic compounds. (springeropen.com)
  • As this plant revealed a high content of phenols along with high antioxidant, antimalarial and xanthine oxidase inhibitory activities, it could have great medicinal value. (springeropen.com)
  • Preparation, Purification, and Identification of Novel Feather Keratin-Derived Peptides with Antioxidative and Xanthine Oxidase Inhibitory Activities. (bvsalud.org)
  • Here, we report on the preparation, purification, and identification of novel peptides with antioxidant and xanthine oxidase (XOD) inhibitory activities from fermented feather broth, using Bacillus licheniformis 8-4. (bvsalud.org)
  • In vivo, nitrite conversion to nitric oxide requires the nitrite reductase activity of xanthine oxidase and cytochrome P-450, thus the involvement of these enzymes was also evaluated. (unical.it)
  • We also found that xanthine oxidase is more expressed in C. hamatus than in T. bernacchii, while the opposite was observed concerning cytochrome P-450. (unical.it)
  • Results suggested that in the heart of C. hamatus and T. bernacchii, nitrite is an integral physiological source of nitric oxide with important signaling properties, which require the nitrite reductase activity of xanthine oxidase and cytochrome P-450. (unical.it)
  • Increasing evidence suggests that serum uric acid (UA), a product of xanthine oxidase (XO), may be a useful marker for metabolic, hemodynamic, and functional staging in heart failure (HF) and a valid predictor of survival in HF patients. (nih.gov)
  • Uric acid (UA) is an end product of the purine metabolic pathway catalyzed by xanthine oxidase (XO), with increased levels of UA associated closely with various pathophysiologies [ 1 , 2 ]. (biomedcentral.com)
  • The xanthine oxidase metabolic pathway may contribute to impaired vasodilator capacity in CHF. (nih.gov)
  • During severe liver damage, xanthine oxidase is released into the blood, so a blood assay for XO is a way to determine if liver damage has happened. (wikipedia.org)
  • These enzymes catalyze the oxidation of hypoxanthine to xanthine and can further catalyze the oxidation of xanthine to uric acid. (wikipedia.org)
  • The following chemical reactions are catalyzed by xanthine oxidase: hypoxanthine + H2O + O2 ⇌ xanthine + H2O2 xanthine + H2O + O2 ⇌ uric acid + H2O2 Xanthine oxidase can also act on certain other purines, pterins, and aldehydes. (wikipedia.org)
  • By blocking the conversion of hypoxanthine and xanthine to uric acid, it produces a reduction in serum uric acid concentration and in the urinary excretion of urates. (medscape.com)
  • Upregulated xanthine oxidase activity (through production of toxic free radicals) may contribute to impaired regulation of vascular tone in CHF. (nih.gov)
  • It is suggested that xanthine oxidoreductase, along with other enzymes, participates in the conversion of nitrate to nitrite in mammalian tissues. (wikipedia.org)
  • Type I xanthinuria has been traced directly to mutations of the XDH gene which mediates xanthine oxidase activity. (wikipedia.org)
  • New prenylflavonol glycosides with xanthine oxidase inhibitory activity from the leaves of Cyclocarya paliurus. (medchemexpress.com)
  • The liver xanthine oxidase activity was also significantly reduced by C. verspertilionis aqueous extract at the same dosage. (uthm.edu.my)
  • Urine xanthine oxidase activity in urinary tract infection. (bmj.com)
  • Among the fractions, 40% and 60% Sep-Pak fraction of MeOH extract had stronger xanthine oxidase inhibitory and antioxidant activities. (springeropen.com)
  • Xanthinuria is a rare genetic disorder where the lack of xanthine oxidase leads to high concentration of xanthine in blood and can cause health problems such as renal failure. (wikipedia.org)
  • The natural particle size of fats inside unadulterated cow s milk acts as a shield to protect humans from the milk s xanthine oxidase. (detailshere.com)
  • Another reaction catalyzed by xanthine oxidase is the decomposition of S-nitrosothiols (RSNO), a class of reactive nitrogen species, to nitric oxide (NO), which reacts with a superoxide anion to form peroxynitrite under aerobic conditions. (wikipedia.org)
  • Similarly, superoxide extracellularly generated by xanthine oxidase/xanthine yielded hydroxyl radicals. (cdc.gov)
  • These results indicate that in rats with a single compound 48/80 treatment neutrophils infiltrated into the gastric mucosa participated in the development of acute gastric mucosal lesions and that the xanthine-xanthine oxidase system in the gastric mucosa participated in the progression rather than the formation of the gastric mucosal lesions. (fujita-hu.ac.jp)
  • In the reaction with xanthine to form uric acid, an oxygen atom is transferred from molybdenum to xanthine, whereby several intermediates are assumed to be involved. (wikipedia.org)
  • Please, check our recent publication in Inorganic Chemistry Frontiers, disclosing the complete catalytic mechanism of Xanthine Oxidase. (biosim.pt)
  • In this article, Quantum mechanical/molecular mechanical (QM/MM) methods were used to study the full catalytic mechanism of xanthine oxidase (XO). (biosim.pt)
  • The XO catalyzes the conversion of xanthine (XAN) to uric acid (URC), requiring the presence of a molybdenum cofactor (Moco). (biosim.pt)
  • Increases in the activities of gastric mucosal xanthine oxidase and myeloperoxidase, an index of neutrophil infiltration, and the content of lipid peroxide occurred 0.5 hr after compound 48/80 injection, and these increases were enhanced at 3 hr. (fujita-hu.ac.jp)
  • Halothane anesthesia was found to be hepatotoxic in the rat, as demonstrated by a significant elevation of serum xanthine oxidase (SXO) level. (tau.ac.il)
  • To review the pharmacology, pharmacokinetics, clinical trial data, safety profile, precautions, and place in therapy of febuxostat, a novel nonpurine xanthine oxidase inhibitor in development for the treatment of hyperuricemia and gout. (nih.gov)
  • Here, we demonstrate that febuxostat, a xanthine oxidase inhibitor, alleviates the increase in adipose tissue mass in obese mouse models with a high-fat diet or ovariectomy. (tokushima-u.ac.jp)
  • Febuxostat (Uloric), the other xanthine oxidase inhibitor, is limited by increased cardiovascular and all-cause mortality seen in studies. (aafp.org)
  • sulfite oxidase deficiency is one of the most accepted causes of sulfite hypersensitivity and toxicity. (nih.gov)
  • In the reaction with xanthine to form uric acid, an oxygen atom is transferred from molybdenum to xanthine, whereby several intermediates are assumed to be involved. (wikipedia.org)
  • Using ferricenium hexafluorophosphate, we attempted to gen erate a radical on the pterin cofactor that bidentately coordinates molybdenum in xanthine oxidase. (usuhs.edu)
  • Xanthine oxidase can oxidize substrates in the blood, leading to the formation of oxygen derived free radicals which have been suggested to provide oxidative defence 12 , 13 . (openaccesspub.org)
  • During the reperfusion after an ischemic episode, xanthine oxidase transforms oxygen into superoxide, which leads to oxidative stress and tissues damage. (hindawi.com)
  • New selenoura derivatives were tested for their effect to inhibit the xanthine oxidase and acetylcholinesterase enzymes. (deu.edu.tr)
  • As research reveals new methods to treat uric acid, I will expand my pages on Xanthine Oxidase Inhibitor choice for Gout Patients. (goutpal.com)
  • Overall, the flavan-3-ol found in A. odoratissimus leaves shows the potential to be developed as a xanthine oxidase inhibitor for use in gout therapy. (phcogj.com)
  • Xanthine oxidase (XO) is a crucial target for the treatment of hyperuricemia and gout. (researchgate.net)
  • Xanthine oxidase (XO) plays a vital role in inducing hyperuricemia and increasing the level of superoxide free radicals in blood, and is proved as an important target for gout. (researchgate.net)
  • Xanthine Oxidase from Bovine Milk is a high quality Xanthine Oxidase from bovine milk. (moleculardepot.com)
  • The antimicrobial activity of bovine milk xanthine_oxidase Int Dairy J. 2020 Mar;102:104581. (moleculardepot.com)
  • 3: Clifford AJ, Ho CY, Swenerton H. Homogenized bovine milk xanthine_oxidase: a critique of the hypothesis relating to plasmalogen depletion and cardiovascular disease Am J Clin Nutr. (moleculardepot.com)
  • The isolation of demolybdo xanthine_oxidase from bovine milk Biochem J. 1988 Nov 1;255(3):949-56. (moleculardepot.com)
  • 5: Briley MS, Eisenthal R. Association of xanthine_oxidase with the bovine milk-fat-globule membrane Biochem J. 1974 Oct;143(1):149-57. (moleculardepot.com)
  • Effects of industrial heat treatments on the kinetics of inactivation of antimicrobial bovine milk xanthine_oxidase NPJ Sci Food. (moleculardepot.com)
  • Simple, high-yield purification of xanthine_oxidase from bovine milk J Biochem Biophys Methods. (moleculardepot.com)
  • Copurification of bovine milk xanthine_oxidase and immunoglobulin Arch Biochem Biophys. (moleculardepot.com)
  • Free and membrane-bound xanthine oxidase in bovine milk during cooling and heating J Dairy Sci. (moleculardepot.com)
  • 10: Silanikove N, Shapiro F, Leitner G. Posttranslational ruling of xanthine oxidase activity in bovine milk by its substrates Biochem Biophys Res Commun. (moleculardepot.com)
  • This study investigated the relationship between serum xanthine oxidase (XOD) activity and the occurrence of diabetic peripheral neuropathy ( DPN ) in type 2 diabetes mellitus (T2DM) patients . (bvsalud.org)
  • In addition, a role for xanthine oxidase in antimicrobial defence, similar to NADPH oxidase in phagocytes is possible. (openaccesspub.org)
  • 1996. Tautomerism of xanthine and alloxanthine: a model for substrate recognition by xanthine oxidase . (ub.edu)
  • During severe liver damage, xanthine oxidase is released into the blood, so a blood assay for XO is a way to determine if liver damage has happened. (wikipedia.org)
  • Xanthine oxidase was extracted, purified and characterized from sheep liver (SLXO). (openaccesspub.org)
  • The sheep liver xanthine oxidase was homogeneously purified 31.8 folds with 3.5 U/mg specific activity and 24.1% recovery. (openaccesspub.org)
  • In this project, we study the binding of small molecules to xanthine oxidase (XOD). (wisconsin.edu)
  • 1997. Role of tautomerism of 2-azaadenine and 2-azahypoxanthine in substrate recognition by xanthine oxidase . (ub.edu)
  • Type I xanthinuria has been traced directly to mutations of the XDH gene which mediates xanthine oxidase activity. (wikipedia.org)
  • Xanthine Oxidase Activity in Type 2 Diabetes Mellitus Patients with and without Diabetic Peripheral Neuropathy. (bvsalud.org)
  • Xanthine crystalluria has been reported in only three patients. (nih.gov)
  • Flavan-3-ol interacts with xanthine oxidase through hydrogen bonding with amino acid residues in the form of Arginine 912 and Lysine 1045. (phcogj.com)
  • Ceruloplasmin exhibits a copper-dependent oxidase activity, which is associated with possible oxidation of Fe 2+ (ferrous iron) into Fe 3+ (ferric iron), therefore assisting in its transport in the plasma in association with transferrin, which can only carry iron in the ferric state. (bionity.com)
  • The purpose of this project is to determine the mechanisms by which chronic stress contributed to cerebrovascular dysfunction and cognitive decline, and their relationship with Alzheimer's disease, with a focus on the mechanistic role of xanthine oxidase. (wvu.edu)
  • To evaluate the role of xanthine oxidase and iron-dependent lipid peroxidation (which are purported mechanisms of reperfusion injury) in the pathogenesis of GDV-related mortality, we created experimental GDV in 21 dogs. (nih.gov)
  • Xanthine oxidase (XO), was the focus of recent clinical trials and epidemiological studies. (nih.gov)
  • The apparent Km for xanthine oxidase at optimum pH 7.6 was found to be 0.9 mM xanthine. (openaccesspub.org)