Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.17.3.2 (xanthine oxidase)
 8,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The fluorescent nucleotide analogues (the 5'-mono-, di-, and triphosphates of lin-benzoguanosine, lin-benzoxanthosine, and lin-benzoinosine) have been prepared for use as dimensional probes of enzyme binding sites. They have quantum yields in aqueous solution of 0.39, 0.55, and 0.04 and fluorescent lifetimes of 6, 9, and approximately equal to 1.5 nsec, respectively. lin-Benzoinosine 5'-monophosphate is a substrate for xanthine oxidase (xanthine:oxygen oxidoreductase, EC 1.2.3.2), providing lin-benzoxanthosine 5'-monophosphate, and lin-benzoinosine 5'-diphosphate is a substrate for polynucleotide phosphorylase (polyribonucleotide:orthophosphate nucleotidyltransferase. EC 2.7.7.8), giving poly(lin-benzoinosinic acid). The benzologues of the purine diphosphates are substrates for pyruvate kinase (ATP:pyruvate 2-O-phosphotransferase, EC 2.7.1.40), which is used to prepare the triphosphates.
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PMID:Synthesis of fluorescent nucleotide analogues: 5'-mono-, di-, and triphosphates of linear-benzoguanosine, linear-benzoinosine, and linear-benzoxanthosine. 29 62

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

1. Cellulose acetate zymograms of alcohol dehydrogenase (ADH), aldehyde dehydrogenase, sorbitol dehydrogenase, aldehyde oxidase, "phenazine" oxidase and xanthine oxidase extracted from tissues of inbred mice were examined. 2. ADH isozymes were differentially distributed in mouse tissues: A2--liver, kidney, adrenals and intestine; B2--all tissues examined; C2--stomach, adrenals, epididymis, ovary, uterus, lung. 3. Two NAD+-specific aldehyde dehydrogenase isozymes were observed in liver and kidney and differentially distributed in other tissues. Alcohol dehydrogenase, aldehyde oxidase, "phenazine" oxidase and xanthine oxidase were also stained when aldehyde dehydrogenase was being examined. 4. Two aldehyde oxidase isozymes exhibited highest activities in liver. 5. "Phenazine oxidase" was widely distributed in mouse tissues whereas xanthine oxidase exhibited highest activity in intestine and liver extracts. 6. Genetic variants for ADH-C2 established its identity with a second form of sorbitol dehydrogenase observed in stomach and other tissues. The major sorbitol dehydrogenase was found in high activity in liver, kidney, pancreas and male reproductive tissues.
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PMID:Electrophoretic analyses of alcohol dehydrogenase, aldehyde dehydrogenase, aldehyde oxidase, sorbitol dehydrogenase and xanthine oxidase from mouse tissues. 31 79

In animals the terminal step in the pathway for degradation of sulphur-containing amino acids is the oxidation of sulphite to sulphate. This reaction is catalysed by the enzyme sulphite oxidase. The enzyme contains molybdenum and a cytochrome b5 type haem, is localized in the mitochondrial intermembrane space and transfers electrons from sulphite to cytochrome c on the inner membrane. The sulphite oxidase protein has a molecular weight of 110 000 (chicken) to 122 000 (human) and exists as a dimer of identical subunits. The haem and molybdenum cofactors are present on separate domains of the molecule. The structure of the molydbenum cofactor has not been worked out in detail, but this cofactor is known to be present in many other molybdoenzymes including xanthine oxidase and nitrate reductase. Three cases of genetic sulphite oxidase deficiency in humans have been reported. The three affected children displayed mental retardation, neurological abnormalities and dislocated ocular lenses. The biochemical basis for lack of enzyme activity in each case has been studied. All three have been shown to lack the sulphite oxidase protein, but in one case this appears to be secondary to a defect in synthesis of the molybdenum cofactor. Sulphite oxidase deficiency has been produced in the rat by administration of high levels of tungsten. Sulphite oxidase-deficient animals are particularly susceptible to the toxic effects of sulphite and atmospheric sulphur dioxide.
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PMID:The oxidation of sulphite in animals systems. 39 60

In a 37 year old renal transplant woman haemolytic anaemia was observed in the course of a combined azathioprine-allopurinol therapy. Azathioprine is converted to 6-mercaptopurine, which then catalyzed by xanthine oxidase is oxidized to 6-thiouric acid. When allopurinol and azathioprine are administered simultaneously, high 6-mercaptopurine concentrations in plasma may be expected because of inhibition of xanthine oxidase activity by allopurinol. We assume that elevated plasma 6-mercaptopurine concentration could possibly be responsible for haemolytic anaemia in this renal transplant patient.
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PMID:[Hemolysis after combined azathioprine and allopurinol therapy]. 40 Feb 13

A screening method has been established for PNP deficiency. This enzyme activity in dried blood absorbed on filter paper can be detected by the formation of a blue insoluble formazan with a gel containing inosine, xanthine oxidase, MTT-tetrazolium, and phenazine methosulfate. The color change is very clear and definite and no false results have been obtained in the testing of 256 enzyme-positive and 107 enzyme-negative samples. The enzyme activity in dried blood on filter paper is so stable at room temperature that samples can be mailed. A screening method for ADA deficiency was developed, also depending on the color change of MTT-tetrazolium. Although the test is slightly more expensive than that developed by Moore and Meuwissen, its accuracy is greater. A common screening method for detecting deficiencies of either PNP or ADA is described.
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PMID:Screening for primary immunodeficiencies associated with purine nucleoside phosphorylase deficiency or adenosine deaminase deficiency. 40 94

The distribution of enzymes involved in purine degradation in fish and crustaceous liver was examined by centrifugation in a sucrose density gradient. In mackerel, yellow mackerel, and prawn liver and mantis club hepatopancreas, uricase and allantoinase were located only in the peroxisomes and in the soluble fraction from broken peroxisomes, and allantoicase was located only in the peroxisomes. Uricase and allantoinase seem to be located in the peroxisomal matrix and allantoicase in the peroxisomal membrane. Adenase, guanase, and xanthine oxidase were present only in the soluble fraction of mackerel liver.
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PMID:Degradation of uric acid to urea and glyoxylate in peroxisomes. 44 47

Xanthine oxidase (xanthine:oxygen oxidoreductase, EC 1.2.3.2) supplemented with an electron donor could catalyze the cis-trans isomerization of 3-(5-nitro-2-furyl)-2-(2-furyl)acrylamide, 3-(5-nitro-2-furyl)-2-phenylacrylamide and 3-(5-nitro-2-furyl)-2-(2-furyl)acrylonitrile. The direction of isomerization (cis leads to trans, cis in equilibrium trans or trans leads to cis) is dependent on the chemical structure of these nitrofuran derivatives. Lipoyl dehydrogenase (NADH:lipoamide oxidereductase, EC 1.6.4.3), DT-diaphorase (NAD(P)H:(quinone-acceptor) oxidoreductase, EC 1.6.99.2) and liver microsomes could also catalyze the conversion of cis-3-(5-nitro-2-furyl)-2-(2-furyl)acrylamide to its trans isomer in the presence of an appropriate electron donor. Such isomerizing activity of these enzymes is much higher than their nitro-reducing activity. In addition, the cis-trans isomerization of some nitrofuran derivatives was demonstrated with the liver slices and the small intestines of rats. A new cis-trans isomerization mechanism which is based on transfer of a single electron by an enzyme system to a nitrofuran derivative to give the radical-anion was proposed. This postulated mechanism was supported by the preliminary experiments using pulse radiolysis technique.
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PMID:Enzymic cis-trans isomerization of nitrofuran derivatives: isomerizing activity of xanthine oxidase, lipoyl dehydrogenase, DT-diaphorase and liver microsomes. 45 30

The role of sulfhydryls in the protection of human polymorphonuclear neutrophils against extracellular oxidant attack was investigated by simultaneously exposing polymorphonuclear neutrophils to the thiol-oxidizing agent diamide and the oxidant-generating system xanthine-xanthine oxidase. Neither diamide nor the oxidants generated by the xanthine-xanthine oxidase system alone impaired the burst in chemiluminescence, hexose monophosphate shunt activity or formate oxidation normally seen during polymorphonuclear neutrophil phagocytosis. Incubation of the polymorphonuclear neutrophils simultaneously with diamide and xanthine-xanthine oxidase markedly impaired polymorphonuclear neutrophil phagocytosis, hexose monophosphate shunt activity, chemiluminescence and formate oxidation. Although the polymorphonuclear neutrophils exposed to diamide and xanthine-xanthine oxidase did not respond to a variety of phagocytizable stimuli, trypan blue exclusion was normal and hexose monophosphate shunt activity could be stimulated by diamide. The damaging effect of the diamide xanthine-xamthine oxidase system could be blocked by the addition of superoxide dismutase or catalase, but not by hydroxyl radical or singlet oxygen scavengers. We hypothesize that an unidentified population of thiols may play a role in protecting the polymorphonuclear neutrophil from endogenously derived oxidants.
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PMID:The effect of oxidant stress on diamide-treated human granulocytes. 46 44

This study comprises of 48 normal men as control group and 49 patients with various stages of bladder carcinoma. Serum xanthine oxidase and uric acid levels were determined. Assessment in terms of changes of the enzyme xanthine oxidase was carried out prior and after surgery as a short-term follow-up. There was a significant fall of serum xanthine oxidase in patients with bladder carcinoma; it also varied with the stage of cancer.
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PMID:Serum xanthine oxidase in bladder carcinoma. 47 29


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