Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P47989 (xanthine oxidase)
 8,633 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Inhibition by aurinetricarboxylic acid (ATA) of glucose-6-phosphate (G6P) dehydrogenase was "competitive" with respect to G6P and "mixed type" with respect to NADP+. Inhibited enzyme bound two molecules of ATA. Kinetic constants, Km, Ki at varying pH suggested possible binding of the inhibitor by the sulfhydryl of the enzyme; of the several enzymes tested only milk xanthine oxidase and G6P dehydrogenase from bovine adrenal was inhibited by ATA.
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PMID:Aurinetricarboxylic acid: a potent inhibitor of glucose-6-phosphate dehydrogenase. 1 74

A protein fraction, which did not contain NADP [or NADPH]-dependent aldehyde reductase as well as NAD [or NADP]-dependent aldehyde dehydrogenases, but which catalyzed oxidation of fatty-aromatic aldehydes, was isolated from extract of rat liver tissue using ammonium sulfate fractionation combined with gradient syvorptive chromatography on DEAE-Sephadex A-25 [or Molselect DEAE-25], CM-Sephadex C-25 and gel-filtration on Sephadex G-200. Investigations of molecular weight and catalytic properties of the protein fraction obtained enabled to identify it with xanthine oxidase [EC 1.2.3.2]. Aldehyde dehydrogenases as well as xanthine oxidase are involved in oxidation of fatty-aromatic aldehydes to corresponding fatty acids, besides the reduction of the aldehydes to alcohols, catalyzed by aldehyde reductase and alcohol dehydrogenases.
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PMID:[Oxidation of fatty-aromatic aldehydes in liver tissues]. 3 12

Two proteins (P1 and P2, with weights of 57,500 and 27,500 respectively) were isolated from Euglena gracilis. Both proteins show cyanide-insensitive superoxide dismutase activity in the "classical" superoxide dismutase assay, using xanthine-xanthine oxidase as O2.- generator. If O2.- is generated chemically (autoxidation of reduced anthraquinone), photochemically (illuminated riboflavine) or pulse radiolytically, only protein P1 but not P2 shows SOD activity. Protein P1 contains 1 g atom (determined: 0.82) iron (no Mn or Cu) per mole protein and may thus be defined as iron-superoxide dismutase. Protein P2, showing the spectral properties of a flavoprotein, exhibits the activities of ferredoxin-NADP-oxidoreductase and "diaphorase". The cyanide-insensitive SOD-activity of this Diaphorase" in the xanthine oxidase-assay for superoxide dismutase makes this classical and commonly used test unreliable for assay cyanide insensitive SOD activities. The existence of the "prokaryote-type" of superoxide dismutase (Fe-SOD) in Euglena gracilis is exceptional for an eukaryotic, autotrophically grown organisms.
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PMID:Cyanide insensitive iron superoxide dismutase in Euglena gracilis. Comparison of the reliabilities of different test systems for superoxide dismutases. 22 43

1. Rate sedimentation and isopycnic centrifugation were used to analyse the subcellular sites of enzymes in homogenates of goldfish intestinal mucosa. 2. The results allowed the following allocations to be made: carnitine acetyl transferase-mitochondrial and peroxisomal, xanthine dehydrogenase and NAD: alpha-glycerophosphate dehydrogenase soluble phase, NADP: isocitrate dehydrogenase soluble phase and mitochondrial, and 2-naphthyl laurate hydrolase microsomal and/or brush border. 3. Histochemistry confirmed the use of alkaline phosphatase and 1-naphthyl acetate esterase as brush border and microsome markers respectively. 4. Urate oxidase, allantoinase, allantoicase, xanthine oxidase and glycollate/lactate oxidase, activities were undetectable, and 1-naphthyl palmitate hydrolase was present only as a contaminant from pancreas.
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PMID:Intestinal peroxisomes of goldfish (Carassius auratus)--examination for hydrolase, dehydrogenase and carnitine acetyltransferase activities. 31 95

A new method for the determination of xanthine oxidase activity with xanthine or hypoxanthine is described. The hydrogen peroxide produced by the oxidation of the substrates is reduced by catalase in the presence of high concentrations of ethanol. The acetaldehyde formed is further oxidized by aldehyde dehydrogenase NAD or NADP-dependent. The reduction rate of the coenzymes were measured at 334 nm and utilized as indicators for the xanthine oxidase. The sensitivity of the method with xanthine as substrate can be doubled by the addition of uricase, which oxidizes uric acid to allantoin.
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PMID:A new spectrophotometric assay for enzymes of purine metabolism. I. Determination of xanthine oxidase activity. 48 56

A new method for the determination of guanase is described. Xanthine, the product of the guanase reaction, is oxidized by xanthine oxidase, forming uric acid and hydrogen peroxide. Hydrogen peroxide is further reduced to water by catalase in the presence of ethanol. The acetaldehyde formed in this reaction step is dehydrogenated NAD or NADP dependent by aldehyde dehydrogenase. The NADH or NADPH production is measured and utilized for the calculation of the guanase activity. The sensitivity of the method can be doubled by the addition of uricase, which oxidizes uric acid to permit the formation of another mole of hydrogen peroxide.
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PMID:A new spectrophotometric assay for enzymes of purine metabolism. II. Determination of guanase activity. 48 57

The rates of NADH oxidation in presence of xanthine oxidase increase to a small and variable extent on addition of high concentrations of lactate dehydrogenase and other dehydrogenases. This heat stable activity is similar to polyvanadate-stimulation with respect to pH profile and SOD sensitivity. Isocitric dehydrogenase (NADP-specific) showed heat labile, SOD-sensitive polyvanadate-stimulated NADH oxidation activity. Polyvanadate-stimulated SOD-sensitive NADH oxidation was also found to occur with riboflavin, FMN and FAD in presence of a non-specific protein, BSA, suggesting that some flavoproteins may possess this activity.
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PMID:Stimulation of NADH oxidation by xanthine oxidase and polyvanadate in presence of some dehydrogenases and flavin compounds. 178 72

NAD(P)-linked aldehyde dehydrogenases catalyze the oxidation of a wide variety of aldehydes. Thirteen of these enzymes have been identified in mouse tissues; eleven are found in the liver. Some are substrate-nonspecific; others are relatively substrate-specific. The present investigation sought to determine which of these enzymes are operative in catalyzing the oxidation of retinaldehyde to retinoic acid, a metabolite of vitamin A that promotes the differentiation of epithelial and other cells. Spectrophotometric and HPLC assays were used for this purpose. Enzyme-catalyzed oxidation of retinaldehyde (25 microM) was restricted to the cytosol (105,000 g supernatant fraction) and occurred at a rate of 211 nmol/min/g liver; oxidation of acetaldehyde (4 mM) by this fraction proceeds about ten times faster. At least 90% of this activity was NAD dependent. Of the approximately 10% that was apparently NAD independent, two-thirds was inhibited by 1 mM pyridoxal, a known inhibitor of aldehyde oxidase. Of the six cytosolic aldehyde dehydrogenases, only two, viz. AHD-2 and AHD-7, catalyzed the oxidation of retinaldehyde to retinoic acid. An additional NAD-dependent enzyme, viz. xanthine oxidase (dehydrogenase form), also catalyzed the reaction. Catalysis by AHD-2 accounted for more than 90% of the total NAD-dependent activity. Km values were 0.7, 0.6 and 0.9 microM, respectively, for the AHD-2-, AHD-7- and xanthine oxidase (dehydrogenase form)-catalyzed reaction. AHD-4, an aldehyde dehydrogenase found in the cytosol of mouse stomach epithelium and cornea, did not catalyze the reaction.
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PMID:Identification of mouse liver aldehyde dehydrogenases that catalyze the oxidation of retinaldehyde to retinoic acid. 188 36

Aldophosphamide, the penultimate cytotoxic metabolite of cyclophosphamide, can be detoxified by an oxidation reaction catalyzed by certain aldehyde dehydrogenases. The selective toxicity of cyclophosphamide is due, at least in part, to a greater expression of the relevant aldehyde dehydrogenase activity in normal cells relative to that expressed in certain tumor cells. Not known at the onset of this investigation was which of the several known mouse aldehyde dehydrogenases catalyze this reaction. Twelve enzymes that catalyze the NAD(P)-linked oxidation of aldophosphamide, acetaldehyde, benzaldehyde, and/or octanal were chromatographically resolved from mouse liver. Four of these appear to be novel; four others were determined to be betaine aldehyde dehydrogenase, succinic semialdehyde dehydrogenase, glutamic gamma-semialdehyde dehydrogenase, and xanthine oxidase (dehydrogenase). An additional aldehyde dehydrogenase, namely AHD-4, was semipurified from stomach. The stomach enzyme and nine of the hepatic enzymes catalyze the oxidation of aldophosphamide. Km values for these reactions range from 16 microM to 2.5 mM. The relevant aldehyde dehydrogenase of major importance varies with the tissue. In the liver, the major cytosolic aldehyde dehydrogenase, namely AHD-2, accounts for greater than 60% of total hepatic aldehyde dehydrogenase-catalyzed aldophosphamide (160 microM) detoxification. Succinic semialdehyde dehydrogenase (AHD-12) and three of the novel hepatic aldehyde dehydrogenases, namely AHD-8, AHD-10, and AHD-13, also contribute significantly to total hepatic aldehyde dehydrogenase-catalyzed aldophosphamide detoxification. In the stomach, AHD-4 and AHD-8 account for approximately 86% of total aldehyde dehydrogenase-catalyzed aldophosphamide (160 microM) detoxification. AHD-2 was not found in this tissue. Of all the aldehyde dehydrogenases examined, AHD-2 and AHD-8 were estimated to be the most efficient catalysts of aldophosphamide oxidation. Thus, these enzymes would seem most likely to be operative when tumor cells acquire aldehyde dehydrogenase-mediated cyclophosphamide resistance.
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PMID:Identification of the mouse aldehyde dehydrogenases important in aldophosphamide detoxification. 237 64

A method was developed to separate guanase by agarose gel electrophoresis and to detect its activity by staining of the bands with a mixture of the enzymes xanthine oxidase, catalase, and aldehyde dehydrogenase, the coenzyme NADP+, and a substrate of guanine, ethanol, phenazine methosulfate, nitrotetrazolium blue, and KCN in Tris-(hydroxymethyl)methylamine buffer (pH 8.0). Serum samples showed bands 1 (faster moving) and 2 corresponding to the positions of albumin and alpha 2-globulin, respectively, found by serum protein staining. The same bands were detected with guanase from human liver and kidney, although band 2 from the latter samples was not as distinct as that from the liver samples.
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PMID:Analysis of guanase by agarose gel electrophoresis and activity staining. 241 96


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