Topic
Xanthine
About: Xanthine is a research topic. Over the lifetime, 4046 publications have been published within this topic receiving 129820 citations. The topic is also known as: Xanthine.
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TL;DR: Peroxidase was present in all vertebrates and in those invertebrates that burrow in soil and detritus and aldehyde oxidase was widely distributed among molluscs, crustaceans, insects and alll the vertebrate classes except birds.
Abstract: 1. 1. Seventy-nine animal species were surveyed spectrophotometrically for peroxidase, aldehyde oxidase, xanthine oxidase and, in fewer species, xanthine dehydrogenase activites. 2. 2. None of the four oxidases was measurable in phytogenetically primitive species. 3. 3. Twelve species displayed peroxidase alone, eleven species displayed xanthine or aldehyde oxidase alone and thirty-three species displayed peroxidase and one, two or three of the other oxidases. 4. 4. Aldehyde oxidase appeared to be phylogenetically primitive to xanthine dehydrogenase, which in turn was primitive to xanthine oxidase. 5. 5. Aldehyde oxidase was widely distributed among molluscs, crustaceans, insects and alll the vertebrate classes except birds. 6. 6. Peroxidase was present in all vertebrates and in those invertebrates that burrow in soil and detritus. 7. 7. Xanthine dehydrogenase incidence was high in insects and fish. 8. 8. Xanthine oxidase was found with certainty only in birds, mammals and one arachnid. 9. 9. Most uricotelic animals displayed either xanthine oxidase or xanthine dehydrogenase. 10. 10. Two insects appeared to shift from xanthine dehydrogenase in their larval stage to aldehyde oxidase in their adult stage.
39 citations
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TL;DR: The production of uric acid in murine white adipose tissue (mWAT) was reported and that such production was augmented in obese mice, and this was analyzed in human WAT.
Abstract: Objective The production of uric acid in murine white adipose tissue (mWAT), and that such production was augmented in obese mice, was recently reported. However, little is known about the secretion of metabolites associated with purine catabolism in human WAT (hWAT). The present study analyzed this in hWAT. Methods Freshly isolated hWAT and mWAT were cultured. The secretion of metabolites associated with purine catabolism was measured. Tissue distribution profiles of genes associated with purine metabolism and metabolite profiling of adipocytes in hypoxia were analyzed. Results Secretion of hypoxanthine from hWAT was higher than those of xanthine and uric acid. On the other hand, secretion of uric acid was relatively higher than xanthine and hypoxanthine in mWAT. Xanthine oxidoreductase (XOR) mRNA expression levels in hWAT were markedly lower than that in the human liver. In murine tissues, XOR mRNA expression levels in mWAT were comparable with those in the liver. Cultured human adipocytes secreted hypoxanthine, and its secretion was increased under hypoxia. The metabolic analysis of human adipocytes showed that hypoxia increased metabolites associated with de novo biosynthesis of purine nucleotides. Conclusions The present study revealed that hypoxanthine was secreted from human adipose tissue, and the secretion might be increased in local hypoxia.
38 citations
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TL;DR: It appears that nucleotide synthesis is a necessary function of these compounds, with adenosine stimulating the initial growth rate and increasing the response of quiescent cells to low concentrations of serum.
Abstract: Adenosine (10 μM) stimulates the initial growth rate of BHK/21 cells seeded at low but not high density in monolayer culture; it does not affect final cell density or permit growth in agar. In labelling experiments With tritiated thymidine, adenosine also increases the response of quiescent cells to low concentrations of serum. Dialysis of serum to remove oxypurines only marginally reduces its effect on quiescent cell labelling or growth, indicating that BHK/21 cells are able to synthesise purines. The response of quiescent cells to 5% serum is inhibited by high MW (2 × 106) dextran sulphate at 2 μg per milliliter. Low MW dextran sulphate (30,000) and heparin at 20 μg per milliliter produce the same effect. Exogenous adenosine (10 μM) prevents this inhibition. Many other purine derivatives replace adenosine for all the above activities but xanthine is completely inactive in all. It, therefore, appears that nucleotide synthesis is a necessary function of these compounds.
The growth of cells of a polyoma-virus-transformed BHK/21 line in monolayer is not stimulated by exogenous purine, though their colony-forming ability in agar is increased five-fold. The stimulating effects of exogenous purines on normal BHK/21 cells and the absolute requirement for them in the presence of polyanions is discussed in relation to possible mechanisms of growth control.
38 citations
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TL;DR: A significant correlation between inhibitory potency and lipophilicity of the tested uric acid-related compounds was observed and the main determinant of the affinity of xanthine- related compounds is the position of the methyl group.
38 citations
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TL;DR: In this paper, the authors used reversed-phase high-performance liquid chromatography (HPLC) for the quantitative determination of adenosine 5′-triphosphate(ATP), adeno-diphosphate (ADP), inosine 5''-monophosphates(IMP), hypoxanthine(Hyp), xanthine (Xan), ino, and adenoine(Ado) in protein extracts.
Abstract: Analytical conditions for the quantitative determination of adenosine 5′-triphosphate(ATP), adenosine 5′-diphosphate(ADP), inosine 5′-monophosphate(IMP), adenosine 5′-monophosphate(AMP), hypoxanthine(Hyp), xanthine(Xan), inosine(Ino) and adenosine(Ado) in meat extracts by reversed-phase high-performance liquid chromatography (HPLC) were examined. A commercial ODS column with a 5-μm particle diameter was used, and expeimental parameters affecting the separation were discussed. Peaks in chromatograms of meat extracts were identified by retention time, co-injection with standards, absorbance ratios and the enzymatic peak shift method. The procedure proposed was adaptable as an indication of freshness of meat.
38 citations