Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.17.1.4 (xanthine dehydrogenase)
1,236 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous studies have shown that a group of nitrogen catabolic enzymes including xanthine dehydrogenase, purine nucleoside phosphorylase, and tyrosine aminotransferase are all increased in chick liver by dietary protein as well as single amino acids (e.g. methionine) and certain antimetabolites (e.g. hydrazine). A similar enzyme response pattern can be obtained with insulin. This hormone causes an enhanced rate of XDH synthesis and gives nonadditive results with protein, hydrazine and methionine. Furthermore, a vitamin B6 dependency was observed in responses to both high protein diets and insulin, all suggesting a common regulatory mechanism. In this system dietary protein and insulin may act similarly by increasing the availability of amino acids to the liver -- in one case by supplying amino acids through the diet and in the other by increasing amino acid uptake.
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PMID:Regulation of nitrogen catabolic enzymes in chick liver: effects of insulin. 1 91

Magnetic interaction between molybdenum and one of the iron-sulphur centres in milk xanthine oxidase [Lowe, Lynden-Bell & Bray (1972) Biochem. J. 130, 239-249] was studied further, with particular reference to the newly discovered Mo(V) e.p.r.(electron-paramagnetic-resonance) signal, Resting II [Lowe, Barber, Pawlik & Bray (1976) Biochem. J. 155, 81-85]. E.p.r. measurements at 35GHz near to 4.2K showed that the interaction has the same sign at all molybdenum orientations and is ferromagnetic. The predicted splitting of the e.p.r. signal from the reduced iron-sulphur centre, Fe/S I, was observed, Providing positive identification of this as the other interacting species. Chemical modification of the molybdenum environment in xanthine oxidase can change the size of the interaction severalfold, but interaction always remains approximately isotropic. The interaction in turkey liver xanthine dehydrogenase is indistinguishable from that in the oxidase. However, a bacterial xanthine dehydrogenase with different iron-sulphur centres shows rather larger interaction. Guanidinium chloride disturbs the iron-sulphur centres of the oxidase, and when this occurs there is a parallel and relatively small change in the interaction. Removal of flavin from the molecule, or raising the pH to 12.0, changes the interaction slightly without affecting the chromophores themselves. It is concluded that the Fe/S I centre and the Mo are at least 1.0nm and probably nearer 2.5nm apart, and that the conformation of the protein between them is relatively stable up to pH 12.
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PMID:Magnetic coupling of the molybdenum and iron-sulphur centres in xanthine oxidase and xanthine dehydrogenases. 2 47

A method to purify bovine liver xanthine oxidase in described, with which samples of 256-fold specific activity with respect to the initial homogenate are obtained. Bovine liver xanthine oxidase and chicken liver xanthine dehydrogenase with oxygen as electron acceptor exhibit similar profile in pKM and log V versus pH plots. With NAD+ as electron acceptor a different profile in the pKM xanthine plot is obtained for chicken liver xanthine dehydrogenase. However three inflection points at the same pH values appear in all plots. Both enzymes are irreversibly inhibited by pCMB and reversibly by N-ethylmaleimide and by iodoacetamide, with competitive and uncompetitive type inhibitions respectively. These results suggest that NAD+ alters the enzymatic action since its binding to the enzyme antecedes the binding of xanthine to the xanthine oxidase molecule, without undergoing itself any modification. 0.15 M DDT of DTE treatment of bovine liver xanthine oxidase gives to the enzyme a permanent activity with NAD+ without modifying its activity with oxygen. The enzyme thus treated produces parallel straight lines in Lineweaver-Burk plots.
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PMID:[Comparative study of chicken liver xanthine dehydrogenase and bovine liver xanthine oxidase. dehydrogenase activity of xanthine oxidase (author's transl)]. 3 57

Selected biochemical properties, based on hepatocellular function, were assessed in the mouse hepatoma BW7756 and host and/or normal mouse liver. These biochemical properties included (a) alpha-fetoprotein (AFP) production, (b) lipid composition, (c) isozyme patterns and enzyme activities, and (d) cyclic AMP levels. The tumor evidenced an exponential growth phase and vigorous production of AFP in the first 3 weeks following transplant. The concentration of AFP in the sera of tumor-bearing mice increases roughly with the growth of the hepatoma. The percentage of total lipid in the hepatoma was greater than in either normal or host liver; however, the liver displayed more phospholipid than the tumor, while more triglyceride was demonstrable in the hepatoma. Of the 17 isozyme patterns analyzed, seven--acid phosphatase, malate dehydrogenase, aspartate amino-transferase, glucose-6-phosphate dehydrogenase, esterase, lactate dehydrogenase, and xanthine dehydrogenase--were different in the liver and the tumor. The cyclic AMP levels decreased in the tumor and the host spleen from day 10 to day 21; however, slight increases were noted in the tumor and host spleen and liver at day 28. These studies suggested 2--3 weeks posttransplantation as the optimal time for investigational use of this hepatoma.
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PMID:Characterization of murine hepatoma BW7756. I. Selected biochemical properties of liver and hepatoma. 8 49

The steady-state concentrations of glutamine, glutamate and ammonia in the kidney cells might regulate the rate of renal xanthine dehydrogenase activity. Both glutamate and glutamine were found to be effective inhibitors of the renal xanthine dehydrogenase activity in vivo. The inhibition by glutamate depends essentially on the glutaminase inhibition.
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PMID:Regulation of the kidney xanthine dehydrogenase by glutaminase. 9 20

Eighteen alleles of the rosy locus in Drosophila melanogaster were characterized to identify putative nonsense mutants. Seven alleles exhibited no evidence of intragenic complementation, no evidence of immunological complementation, no evidence of immunological cross-reactivity to antibodies elicited by wild type xanthine dehydrogenase (XDH), and of course were completely deficient in measurable XDH activity. It is possible that one or more of these highly negative ry alleles are nonsense mutants. The remaining eleven ry alleles code for XDH molecules that retain some antigenic similarities to the wild type enzyme as assessed by immunoelectrophoresis and six of these eleven were capable of intragenic complementation.
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PMID:An analysis of xanthine dehydrogenase negative mutants of the rosy locus in Drosophila melanogaster. 9 3

Four different genes are known to affect aldehyde oxidase activity (AO) in Drosophila melanogaster. Mutants at each of these loci eliminate AO activity and simultaneously eliminate detectable AO-crossing reacting material (AO-CRM) even though only one is the structural gene for AO (Aldoxn). The other three genes (cin1, lxd and mal) coordinately "control" the levels of activity of AO and two related enzymes, xanthine dehydrogenase (XDH) and pyridoxal oxidase (PO). Contrary to their effects on AO-CRM, neither of these three mutants eliminate XDH-CRM. A model of interaction of these enzymes and genes controlling their activities is discussed.
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PMID:Genetic control of aldehyde oxidase activity and cross-reacting-material in Drosophila melanogaster. 9 42

The stability of immobilized preparations of xanthine oxidase and urate oxidase was studied, and optimized, because of the potential joint use of both enzymes in clinical analysis. Xanthine oxidase was immobilized on cellulose, Sepharose, hornblende, Enzacryl-TIO, and porous glass. Thehalf-lives of these preparations at 30 degree C ranged from 40 min to 5.0 hr. In this respect immobilized enzyme resembled soluble enzyme in dilute solution (0.11 mg/ml), when the half-live was about 3.5 hr. More concentrated enzyme solution (1 mg/ml) had a half-life of 64 hr, and was, therefore, considerably more stable than the untreated immobilized xanthine oxidase preparations. Inclusion of albumen in storage and assay buffer increased the half-life of bound xanthine oxidase. So also did treatment with glutaraldehyde: in the case of xanthine oxidase bound to Enzarcyl-TIO such treatment increased the half-life at 30 degree C from 3 hr to about 100 hr. Immobilized xanthine dehydrogenase was more stable than immobilized xanthine oxidase: the dehydrogenase lost no activity during continuous assay for 5 hr at 30 degree C. The stability of immobilized urate oxidase depended on the quantity of enzyme used and on the time of stirring during immobilization: thus a preparation was made (by stirring urate oxidase (48 mg/g support) with Enzacryl-TIO for 24 hr) which lost no activity during 350 hr at 30 degree C.
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PMID:Studies on the stability of immobilized xanthine oxidase and urate oxidase. 9 90

Genetic mapping of the genes (puu) that encode the enzymes catalysing degradation of purines in Pseudomonas aeruginosa strain PAO has been carried out. Mutants that are deficient in adenine deaminase (puuA), guanine deaminase (puuB), xanthine dehydrogenase (puuC), uricase (puuD), allantoinase (puuE), and/or allantoicase (puuF) were isolated and used for the genetic study. Conjugation by FP5 factor and generalized transduction by phage G101 gave the following map locations of these six genes on the chromosome: hisI--puuB--hisII; trpA,B--puuA--ilv202; met9011--catA1--tyu--nar9011--(puuC, puuD, puuE)--puuF. A close linkage among the puuC, puuD and puuE was demonstrated by the transduction.
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PMID:Chromosomal location of genes participating in the degradation of purines in Pseudomonas aeruginosa. 10 42

The present report summarizes our recent progress in the genetic dissection of an elementary genetic unit in a higher organism, the rosy locus (ry:3--52.0) in Drosophila melanogaster. Pursuing the hypothesis that the rosy locus includes a noncoding control region, as well as a structural element coding for the xanthine dehydrogenase (XDH) peptide, experiments are described that characterize and map a rosy locus variant associated with much lower than normal levels of XDH activity. Experiments are described that fail to relate this phenotype to alteration in the structure of the XDH peptide, but clearly associate this character with variation in number of molecules of XDH per fly. Large-scale fine-structure recombination experiments locate the genetic basis for this variation in the number of molecules of XDH per fly to a site immediately to the left of the XDH structural element within a region previously designated as the XDH control element. Moreover, experiments clearly separate this "underproducer" variant site from a previously described "overproducer" site within the control region. Examination of enzyme activity in electrophoretic gels of appropriate heterozygous genotypes demonstrates the cis-acting nature of this variation in the number of molecules of XDH. A revision of the map of the rosy locus, structural and control elements is presented in the light of the additional mapping data now available.
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PMID:Organization of the rosy locus in Drosophila melanogaster: further evidence in support of a cis-acting control element adjacent to the xanthine dehydrogenase structural element. 10 51


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