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)

Rabbit liver aldehyde oxidase (AO), like milk xanthine oxidase (XO) and chicken liver xanthine dehydrogenase (XDH), possesses the following prosthetic groups: FAD, a functional Mo center, and two spectroscopically distinct iron-sulfur centers, one with gav less than 2.0 (termed Fe/S I) and the other with gav greater than 2.0 (termed Fe/S II) in the reduced enzyme. EPR spectra for the Mov species were found to be nearly identical in AO and XO for a number of enzyme complexes, and the midpoint reduction potentials for functional MoVI/MoV (-359 mV) and MoV/MoVI (-351 mV) were nearly the same in all three enzymes (50 mM phosphate, pH 7.8). A strong magnetic interaction between MoV and reduced Fe/S I, previously detected in XO and XDH, was also found in AO. No MoV-Fe/S II interaction could be detected in AO (nor in XO). In contrast, the order of reduction of Fe/S I and Fe/S II, as measured from their midpoint potentials, is reversed in AO (Em = -207 and -310 mV, respectively) as compared to XO (Em = -280 and -245 mV, respectively) in phosphate buffer at pH 7.8. The oxidized-reduced extinction coefficients at 450 and 550 nm for the two centers are also apparently reversed in AO and XO. Although magnetic interaction between FAD and one or both reduced Fe/S centers has been detected in both AO and XO, no magnetic interaction between the two reduced Fe/S centers themselves was found in AO (although such interaction has been seen in XO). The average FAD reduction potential is substantially more positive in AO (Em for FAD/FADH., -258 mV; FADH./FADH2, -212 mV at pH 7.8) than in XO or XDH. It can be concluded that although the properties and immediate environment of the functional Mo center are conserved in the three Mo hydroxylase enzymes, and all three enzymes possess the same set of prosthetic groups, the properties of the groups which transfer electrons from the Mo to the ultimate electron acceptor can vary substantially in AO, XO, and XDH.
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PMID:Properties of the prosthetic groups of rabbit liver aldehyde oxidase: a comparison of molybdenum hydroxylase enzymes. 628 79

Molybdenum, because of its unique chemistry, is the biological catalyst for reactions in which proton and electron transfer, and possibly oxygen transfer, are coupled. The molybdoenzymes in man are sulphite oxidase, xanthine oxidase/dehydrogenase and aldehyde oxidase. The former is essential for detoxication of the sulphite arising from metabolism of sulphur-containing amino acids, from ingestion of bisulphite preservative and from inhalation of sulphur dioxide, an atmospheric pollutant. Whether, or not, any of the reactions catalysed by xanthine oxidase/dehydrogenase and aldehyde oxidase are necessary for human well-being has yet to be established.
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PMID:The role of molybdenum in human biology. 631 91

In Glossina morsitans morsitans Westwood the locus for glucose-6-phosphate dehydrogenase, G6pd, was found to be in linkage group I, approximately 35 to 42 map units to the left of ocra, the locus for body color. The locus for midgut alkaline phosphatase, Alkph, was found to be in linkage group II, within 0.41 map units of the locus for xanthine oxidase, Xo. The distance from Xo to the locus for aldehyde oxidase, Ao, was confirmed to be about 42 map units. No evidence for genetical recombination was found in male G. m. morsitans.
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PMID:Genetics of Glossina morsitans morsitans (Diptera: Glossinidae). VII. Location of G6pd in linkage group I, and Alkph in linkage group II. 634 Aug 5

Cellulose acetate zymograms of alcohol dehydrogenase (ADH), aldehyde dehydrogenase (AHD), aldehyde reductase (AHR), aldehyde oxidase (AOX) and xanthine oxidase (XOX) extracted from horse tissues were examined. Five ADH isozymes were resolved: three corresponded to the previously reported class I ADHs (EE, ES and SS) (Theorell, 1969); a single form of class II ADH (designated ADH-C2) and of class III ADH (designated ADH-B2) were also observed. The latter isozyme was widely distributed in horse tissues whereas the other enzymes were found predominantly in liver. Four AHD isozymes were differentially distributed in subcellular preparations of horse liver: AHD-1 (large granules); AHD-3 (small granules); and AHD-2, AHD-4 (cytoplasm). AHD-1 was more widely distributed among the horse tissues examined. Liver represented the major source of activity for most AHDs. A single additional form of NADPH-dependent AHR activity (identified as hexonate dehydrogenase), other than the ADHs previously described, was observed in horse liver. Single forms of AOX and XOX were observed in horse tissue extracts, with highest activities in liver.
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PMID:Electrophoretic analyses of alcohol dehydrogenase, aldehyde dehydrogenase, aldehyde reductase, aldehyde oxidase and xanthine oxidase from horse tissues. 637 10

A method has been developed for the determination of aldehyde oxidase. Dimethylaminocinnamaldehyde was taken as substrate. It is oxidized to the corresponding acid and changes ist absorption at 398 nm. Except dissolved oxygen no additional electron acceptor is needed. This alternative assay was found to be about twice as sensitive compared to the method with acetaldehyde and dichlorophenol indophenol. Aldehyde oxidase activity was estimated in the raw extract of livers of pig, sheep and rat. Xanthine oxidase does not interfere.
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PMID:[Method for the photometric determination of aldehyde oxidase activity]. 653 55

Oral administration of phthalazine (50 mg/kg/day) or 1-hydroxyphthalazine (10 mg/kg/day) to female rabbits caused an increase in the specific activity of the hepatic molybdenum hydroxylases aldehyde oxidase and xanthine oxidase, whereas no effect on microsomal cytochrome P-450 activity was observed. The rise in the specific activity of purified aldehyde oxidase fractions was accompanied by a similar increase in molybdenum content. A significant lowering of the Km value for phthalazine was demonstrated with enzyme from treated rabbits whereas Km values for structurally similar substrates such as isoquinoline were unchanged from control values. Iso-electric focusing of DEAE-cellulose fractions showed the presence of an additional band of activity indicating that genuine induction of aldehyde oxidase had occurred in rabbits treated with phthalazine or 1-hydroxyphthalazine.
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PMID:Elevation of molybdenum hydroxylase levels in rabbit liver after ingestion of phthalazine or its hydroxylated metabolite. 654 14

Acyclovir [9-[(2-hydroxyethoxy)methyl]guanine] is an acyclic guanine nucleoside analogue that is widely used clinically as an antiherpetic agent. Its limited absorption in humans after oral administration prompted the search for prodrugs. A congener, referred to as 6- deoxyacyclovir [2-amino-9-[(2-hydroxyethoxy)methyl]-9H-purine], was synthesized and found to be 18 times more water soluble than was acyclovir. Surprisingly, this congener was readily oxidized to acyclovir by xanthine oxidase (EC 1.2.3.2). It was also oxidized by aldehyde oxidase (EC 1.2.3.1) largely to 8-hydroxy-6- deoxyacyclovir [2-amino-8-hydroxy-9-[(2-hydroxyethoxy)methyl]-9H-purine] and then to 8- hydroxyacyclovir [2-amino-6,8-dihydroxy-9[(2-hydroxyethoxy)methyl]-9H-purine]. 6- Deoxyacyclovir and the major products of its oxidation by aldehyde oxidase lacked appreciable activity against herpes simplex type I in vitro. On the basis of these results, it was apparent that the success of 6- deoxyacyclovir as a prodrug in vivo would depend upon how well its desired activation by xanthine oxidase competed with the nonactivating oxidations by aldehyde oxidase. In rats dosed orally with 6- deoxyacyclovir , absorption was extensive and the major urinary metabolite was acyclovir. In two human volunteers, urinary excretions of acyclovir were 5-6 times greater than those typically observed after administration of equivalent doses of acyclovir itself. The areas under the plasma concentration-time curves for acyclovir were also 5-6 times greater. Plasma levels of acyclovir peaked soon after ingestion of the prodrug, indicating rapid absorption and metabolic conversion. These results suggested that 6- deoxyacyclovir might have clinical usefulness as a prodrug of acyclovir suitable for oral administration.
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PMID:6-Deoxyacyclovir: a xanthine oxidase-activated prodrug of acyclovir. 658 47

The present study provides evidence that guinea pig and rabbit liver aldehyde oxidase (EC 1.2.3.1) in the presence of its electron donors such as aldehydes or N-heterocyclic compounds functions as a sulfoxide reductase towards sulindac and other sulfoxide compounds. In addition, the study shows that a combination of liver aldehyde oxidase and milk xanthine oxidase also exhibits sulfoxide reductase activity in the presence of xanthine, and electron donor of xanthine oxidase. Based on these facts, we propose a new electron-transfer system consisting of these two flavoenzymes.
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PMID:Sulfoxide reductase activity of liver aldehyde oxidase. 668 61

An acridine antitumor agent, 4'-(9-acridinylamino)methanesulfon-m-anisidide, has been found to be an extremely potent competitive inhibitor of aldehyde oxidase (EC 1.2.3.1). The inhibitor constant (Ki) was determined to be 0.06 microM. The degree of enzyme inhibition was quite sensitive to small changes in the structure of the inhibitor's anisidide moiety. Drug inhibition was specific for aldehyde oxidase and inhibition was not detected with the other mammalian molybdenum iron-sulfur flavoenzyme, xanthine oxidase (EC 1.2.3.2). Members of the 4'-(9-acridinylamine)methanesulfonanilide series might be useful probes in the study of the structure and function of aldehyde oxidase.
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PMID:An extremely potent anilinoacridine inhibitor of aldehyde oxidase. 668 24

Benznidazole (Bz) (N-benzyl-2-nitro-1-imidazole-acetamide) is a drug used against Chagas' disease. Rat liver microsomal and cytosolic fractions, but not mitochondria, exhibited Bz nitroreductase activity under anaerobic conditions in the presence of NADPH. Microsomal nitroreductase activity was enhanced by FAD and was inhibited totally by oxygen and partially by carbon monoxide. Liver cystosol fraction was able to reduce Bz nitrogroups in the presence of either N-methylnicotinamide or hypoxanthine as substrates. These enzyme activities were inhibited by menadione or allopurinol respectively. Under every experimental condition leading to enzymatic reduction of Bz nitrogroups and its inhibition or enhancement, reactive metabolites that bind covalently to proteins were also produced. This covalent binding was effectively prevented by reduced glutathione. Results suggest the participation of cytochrome P-450 and cytochrome c reductase in liver microsomal processes and of xanthine oxidase and aldehyde oxidase in liver cytosolic processes of Bz nitroreduction and activation to reactive metabolites that bind covalently to proteins. Possible pharmacological and toxicological implications of the described observations were discussed.
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PMID:Reductive metabolism and activation of benznidazole. 671 14


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