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)

The activity of the molybdenum hydroxylase, aldehyde oxidase, was determined in crude homogenates and (NH4)2SO4 fractions prepared from guinea pig liver, lung, kidney, intestine, spleen and heart. Xanthine oxidase was also measured in (NH4)2SO4 fractions. In each case, xanthine oxidase levels were lower than those of aldehyde oxidase; activity of the latter enzyme was highest in the liver, whereas xanthine oxidase was predominant in the small intestine. There was no significant difference in the activity of either molybdenum hydroxylase between tissues taken from male and female guinea pigs.
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PMID:Tissue distribution of the molybdenum hydroxylases, aldehyde oxidase and xanthine oxidase, in male and female guinea pigs. 344 90

Isoelectric focusing (IEF) and cellulose acetate electrophoresis were used to examine the multiplicity and distribution of aldehyde dehydrogenases (ALDHs), aldehyde oxidase (AOX) and xanthine oxidase (XOX) from tissues of olive and yellow baboons. Five ALDHs were resolved and distinguished on the basis of their differential tissue and subcellular distribution or substrate specificity. Some ALDHs exhibited multiple activity zones. Baboon liver ALDHs were differentially distributed in cytosol (ALDHs II, III and V) and large granular (mitochondrial) fractions (ALDHs I and IV). The major liver ALDHs (I and II) were also broadly distributed in other tissues, as was the major stomach enzyme (ALDH-III). Three brain ALDHs were resolved, which were also differentially distributed between large granular (mitochondrial) (ALDHs I and IV) and cytosolic (ALDH-III) fractions. Electrophoretic variability between individuals was observed for the major liver mitochondrial isozyme (ALDH-I), the major stomach isozyme (ALDH-III) and the minor liver isozymes (ALDHs IV and V). Single forms of AOX and XOX were found in baboon tissue extracts, with the highest activities in liver (AOX) and intestine extracts (XOX). Both oxidases were predominantly localized in the liver soluble fraction.
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PMID:Aldehyde dehydrogenases, aldehyde oxidase and xanthine oxidase from baboon tissues: phenotypic variability and subcellular distribution in liver and brain. 375 5

The stabilized carbonium ion salt, tropylium tetrafluoroborate, was oxidized to tropone (cycloheptatrienone) by rabbit liver aldehyde oxidase but not by the closely related molybdenum hydroxylase, xanthine oxidase. The tropylium cation is an aromatic hydrocarbon which lacks the aldehyde, imine, or iminium functional groups present in other substrates of aldehyde oxidase. The unique structural features of the tropylium ion should make it a useful tool for mechanistic studies of aldehyde oxidase.
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PMID:Tropylium tetrafluoroborate, a novel substrate for aldehyde oxidase. 377 70

1-Amino- and 1-chlorophthalazine were tested for possible substrate activity with partially purified rabbit-liver aldehyde oxidase and bovine-milk xanthine oxidase. 1-Chlorophthalazine was a more efficient substrate than the parent compound, phthalazine, with either aldehyde oxidase or xanthine oxidase. The oxidation product of 1-chlorophthalazine was identified as 4-chloro-1-(2H)-phthalazinone on the basis of chromatographic, infra-red and mass-spectral data. 1-Aminophthalazine was oxidized by aldehyde oxidase to 4-amino-1-(2H)-phthalazinone but was a competitive inhibitor of xanthine oxidase. Kinetic studies at different pH values indicated that, in each case, it is the unprotonated form of 1-aminophthalazine that reacts with the molybdenum hydroxylases.
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PMID:Reaction of 1-amino- and 1-chlorophthalazine with mammalian molybdenum hydroxylases in vitro. 382 75

The mechanism of the enhancing effect of methyl viologen (MV) and flavin-adenine dinucleotide (FAD) on sulfoxide reduction which is mediated by a combination of aldehyde oxidase (AO) from guinea pig liver and one-electron reducing flavoenzymes, such as milk xanthine oxidase (XO), was examined. The activity of anaerobic reduction of diphenyl sulfoxide (DPSO) to diphenyl sulfide (DPS) was less than 1 nmol/min/mg protein of AO preparation in a system consisting of hypoxanthine, XO and AO. However, the sulfoxide reduction by this system was enhanced about 6- and 100-fold by the additions of FAD and MV, respectively. In the system containing MV or FAD, other one-electron reducing flavoenzymes such as nicotinamide adenine dinucleotide (reduced form) (NADH) dehydrogenase, lipoamide dehydrogenase and glutathione reductase with an appropriate electron donor, could replace XO. The ability of supplemented flavoenzymes to facilitate DPSO reduction correlated with their abilities to reduce MV and FAD. When AO was omitted from the combined system, no sulfoxide reduction was observed. Stoichiometric study revealed that MV semiquinone and FADH2 were oxidized at ratios of 2 and 1 mol, respectively, per mol of DPS formed. These results indicate that either MV or FAD serves as an electron carrier from the supplemented flavoenzymes to AO, a terminal reductase of sulfoxide.
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PMID:Sulfoxide reduction catalyzed by guinea pig liver aldehyde oxidase in combination with one-electron reducing flavoenzymes. 383 63

The interaction of the vasodilator, hydralazine, with the molybdenum hydroxylases, aldehyde oxidase and xanthine oxidase has been investigated. A potent progressive inhibition of rabbit liver aldehyde oxidase, in the presence of substrate, by low concentrations of hydralazine (0.1-1 microM) was observed in vitro but no effect was seen with bovine milk xanthine oxidase. This activity was mirrored in vivo when levels of aldehyde oxidase were significantly decreased in rabbits administered hydralazine (10 mg/kg/day for seven days) whereas hepatic xanthine oxidase activity was unaltered by hydralazine treatment. Various metabolites of hydralazine were synthesized but found to be devoid of in vitro inhibitory activity. Aldehyde oxidase prepared from either guinea pig or baboon liver was inhibited in a similar way to that of rabbit liver.
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PMID:Hydralazine: a potent inhibitor of aldehyde oxidase activity in vitro and in vivo. 384 Oct

Isoelectric focusing and electrophoresis were used to identify the various isozymes of alcohol dehydrogenase (ADH), aldehyde dehydrogenase (ALDH), aldehyde oxidase (AOX), and xanthine oxidase (XOX). ADH types I, II, and III were located primarily in the cytosol fraction of liver, but some activity was found also in the small granule fraction. The ALDH-I and -IV isozymes were found in the large granule fraction, while ALDH-II and -III were present in the cytosol and ALDH-V in the small granule fraction. AOX and XOX each appeared as a single cytosolic form with some small granule activity. The tissue distribution of these isozymes is presented and the physiological role of each enzyme is discussed.
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PMID:Analysis of human alcohol- and aldehyde-metabolizing isozymes by electrophoresis and isoelectric focusing. 389 98

The sensitivity of cultured L1210 and P388 cells sensitive (L1210/0, P388/0) and resistant (L1210/OAP, P388/CLA) to oxazaphosphorines, to 4-hydroperoxycyclophosphamide, ASTA Z-7557, phosphoramide mustard, and acrolein was determined in the absence and presence of known (disulfiram, diethyldithiocarbamate, cyanamide) or suspected [ethylphenyl(2-formylethyl)phosphinate] inhibitors of aldehyde dehydrogenase activity. The L1210/OAP cell line is resistant specifically to the oxazaphosphorines; P388/CLA cells are partially cross-resistant to other cross-linking agents. All four inhibitors of aldehyde dehydrogenase activity potentiated the cytotoxic action of the oxazaphosphorines, 4-hydroperoxycyclophosphamide and ASTA Z-7557, against L1210/OAP and P388/CLA cells; in the presence of a sufficient amount of inhibitor, sensitivity was essentially fully restored in both cases. The inhibitors did not potentiate the cytotoxic action of the nonoxazaphosphorines, phosphoramide mustard and acrolein, against these cell lines. The cytotoxic action of the oxazaphosphorines and nonoxazaphosphorines against L1210/0 and P388/0 cells was not potentiated by any of the aldehyde dehydrogenase inhibitors. Inhibitors of xanthine oxidase or aldehyde oxidase activities did not potentiate the cytotoxic action of the oxazaphosphorines against L1210/OAP cells. These observations strongly suggest that (a) aldehyde dehydrogenase activity is an important determinant with regard to the sensitivity of a cell population to the oxazaphosphorines; (b) L1210/0 and P388/0 cells lack the relevant aldehyde dehydrogenase activity; (c) the phenotypic basis for the resistance to oxazaphosphorines by L1210/OAP cells is aldehyde dehydrogenase activity; and (d) the major reason that P388/CLA cells are resistant to oxazaphosphorines is aldehyde dehydrogenase activity.
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PMID:Restoration of sensitivity to oxazaphosphorines by inhibitors of aldehyde dehydrogenase activity in cultured oxazaphosphorine-resistant L1210 and cross-linking agent-resistant P388 cell lines. 397 23

Isoelectric focusing techniques (IEF) were used to examine the tissue distribution and genetic variability of aldehyde dehydrogenases (AHDs) from inbred strains of mice. Twelve zones of AHD activity were resolved which were differentially distributed between tissues. Liver extracts exhibited highest activity for most enzymes, with the exception of isozymes found in stomach (AHD-4) and testis (AHD-4 and AHD-6). Genetic variants for AHD-1 (liver mitochondrial isozyme) and AHD-4 (stomach isozyme) were examined from inbred strains and F1 hybrid animals. The results were consistent with dimeric subunit structures (designated as A2 and D2 isozymes respectively). IEF patterns for activity variants of testis-specific AHD-6 were identical, with 3-banded phenotypes being observed. pI values for the AHD forms as well as for aldehyde oxidase and xanthine oxidase isozymes, which stain in the absence of coenzyme, were reported.
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PMID:Isoelectric focusing studies of aldehyde dehydrogenases from mouse tissues: variant phenotypes of liver, stomach and testis isozymes. 404 Aug 41

In vitro assembly or complementation of a hybrid assimilatory nitrate reductase was attained by mixing a preparation of nitrate-induced N. crassa mutant nit-1 specifically with acid-treated (pH 2.5) bovine milk or intestinal xanthine oxidase, rabbit liver aldehyde oxidase, or chicken liver xanthine dehydrogenase. The complementation reaction specifically required induced nit-1, the only nitrate reductase mutant of Neurospora that lacked xanthine dehydrogenase and was unable to use hypoxathine or nitrate as a sole nitrogen source. The complementing activities of the above acid-treated enzymes correspond to their xanthine or aldehyde oxidizing activity profiles on sucrose density gradients. The resulting soluble, reduced nicotinamide adenine dinucleotide phosphate (NADPH)-nitrate reductases are the same as the Neurospora wild type enzyme in sucrose density gradient profile, molecular weight, substrate affinities, and sensitivity to inhibitors and temperature. By analogy to a similar in vitro complementation of nitrate reductase in mixtures of induced nit-1 and individual nonalleic Neurospora mutants, or uninduced wild type, the complemented nitrate apparently consists of an inducible protein subunit (possessing inducible NADPH-cytochrome c reductase) furnished by nit-1 and a subunit from the acid-treated xanthine or aldehyde oxidizing system which can substitute for the constitutive component furnished by the other mutants or uninduced wild type. The data suggest that Neurospora nitrate reductase and the xanthine oxidizing system and aldehyde oxidase of animals, all of which are molybdenum-containing enzymes catalyzing the reduction of nitrate to nitrite, share a highly similar protein subunit.
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PMID:In vitro assembly of Neurospora assimilatory nitrate reductase from protein subunits of a Neurospora mutant and the xanthine oxidizing or aldehyde oxidase systems of higher animals. 439 66


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