Showing papers on "Xanthine published in 1980"
TL;DR: A patient suffering from a combined deficiency of sulfite oxidase and xanthine dehydrogenase shows severe neurological abnormalities, dislocated ocular lenses, and mental retardation, and the metabolic defect responsible for loss of both enzyme activities appears to be at the level of the molybdenum cofactor common to the two enzymes.
Abstract: A patient suffering from a combined deficiency of sulfite oxidase (sulfite dehydrogenase; sulfite:ferricytochrome c oxidoreductase, EC 1.8.2.1) and xanthine dehydrogenase (xanthine:NAD+ oxidoreductase, EC 1.2.1.37) is described. The patient displays severe neurological abnormalities, dislocated ocular lenses, and mental retardation. Urinary excretion of sulfite, thiosulfate, S-sulfocysteine, taurine, hypoxanthine, and xanthine is increased in this individual, while sulfate and urate levels are drastically reduced. The metabolic defect responsible for loss of both enzyme activities appears to be at the level of the molybdenum cofactor common to the two enzymes. Immunological examination of a biopsy sample of liver tissue revealed the presence of the xanthine dehydrogenase protein in near normal amounts. Sulfite oxidase apoprotein was not detected by a variety of immunological techniques. The plasma molybdenum concentration was normal; however, hepatic content of molybdenum and the storage pool of active molybdenum cofactor present in normal livers were below the limits of detection. Fibroblasts cultured from this patient failed to express sulfite oxidase protein or activity, whereas those from the parents and healthy brother of the patient expressed normal levels of this enzyme.
146 citations
TL;DR: A reversed-phase "high-pressure" liquid-chromatographic method is described for simultaneous analysis for 5-fluorouracil, uridine, hypoxanthine, xanthine), uric acid, allopurinol, and oxipurInol to determine mean values for those compounds in normal human plasma.
Abstract: A reversed-phase "high-pressure" liquid-chromatographic method is described for simultaneous analysis for 5-fluorouracil, uridine, hypoxanthine, xanthine, uric acid, allopurinol, and oxipurinol. Separation was optimal with phosphate buffer (50 mmol/L, pH 4.60) as eluent. A simple acid extraction procedure yielded quantitative recoveries and permitted adequate separation for interfering peaks. Compounds were identified by their retention times, absorbance ratios, co-elution with standards, and enzymatic shifts. With a computerized integrator we quantitated these compounds in widely varying concentrations with a single injection. The limit of sensitivity was 0.1 mumol/L for the compounds studied. This method was applied to determine mean values for those compounds in normal human plasma. They are (in mumol/L): uric acid 276 (SD 55), hypoxanthine 0.46 (SD 0.21), xanthine 0.40 (SD 0.27), and uridine 4.50 (SD 1.70). Erythrocytes and platelets can continue to release hypoxanthine and xanthine into plasma or serum after a blood specimen has been drawn. We believe this explains the higher values previously reported for hypoxanthine and xanthine in serum.
133 citations
TL;DR: Allantoin and allantoic acid are the major forms of nitrogen transported from soybean nodules to other parts of the plant and data suggest that the xanthine-oxidizing enzyme in the nodule is an NAD(+)-dependent xanthin dehydrogenase (EC 1.2.1.37) which is present only in the cytosol fraction.
Abstract: Allantoin and allantoic acid are the major forms of nitrogen transported from soybean nodules to other parts of the plant. Neither the pathway or the site of ureide synthesis has been demonstrated in root nodules.Bacteroid and cytosol (plant portion) fractions were prepared and the purity of each fraction was determined with marker enzymes. A pathway for ureide synthesis by the cytosol fraction of soybean nodules was established by measuring allantoic acid or NADH production. Enzymes were found in the cytosol fraction which would synthesize allantoic acid from the product of de novo purine synthesis, inosine-5'-monophosphate. Allantoic acid production by the nodule cytosol fraction with inosine-5'-monophosphate, inosine, xanthosine-5'-monophosphate, xanthosine, hypoxanthine, or xanthine as substrates was NAD(+)-dependent and blocked by allopurinol. Both bacteroid and cytosol fractions were capable of allantoic acid production with uric acid or allantoin as substrates. Allantoic acid synthesis from these two substrates was neither dependent on NAD(+) nor inhibited by allopurinol.These data suggest that the xanthine-oxidizing enzyme in the nodule is an NAD(+)-dependent xanthine dehydrogenase (EC 1.2.1.37) which is present only in the cytosol fraction. The NADH production by this enzyme plays a critical and energy-conserving role in the ureide synthetic pathway. Cytosol xanthine dehydrogenase activity was sufficient for the metabolism of fixed N since calculations showed similar rates of N(2) fixation and xanthine oxidation.
99 citations
01 Jan 1980
TL;DR: The group of enzymes collectively and descriptively known as the molybdenum iron-sulphur flavin hydroxylases includes aldehyde oxidation, xanthine oxidase, andxanthine dehydrogenase, which are among the most unique of proteins.
Abstract: Publisher Summary The group of enzymes collectively and descriptively known as the molybdenum iron-sulphur flavin hydroxylases includes aldehyde oxidase, xanthine oxidase, and xanthine dehydrogenase. As a group and as individuals, they are among the most unique of proteins. The promiscuity of these enzymes is reflected in their behavior with respect to substrates. Distinctions between aldehyde and xanthine oxidases and between xanthine oxidase and dehydrogenase have not always been made. Aldehyde oxidase, xanthine oxidase, and xanthine dehydrogenase catalyze, though at widely different rates, the hydroxylation of a wide variety of purines, pteridines, pyrimidines, other heterocyclic nitrogenous compounds, and aldehydes, whether aliphatic, aromatic, or heteroaromatic. These enzymes differ not only in substrate specificity but also with respect to the position on the substrate that is hydroxylated. This is most evident with substrates, such as purines and pteridines, having more than one site available for hydroxylation.
86 citations
TL;DR: The principal nitrogenous solutes produced from N 2 -fixation and exported from the nodules of cowpea were allantoin and allantoic acid, and the following evidence suggests that these ureides were derived from purines.
82 citations
Journal Article•
TL;DR: It is proposed that the semiquinone free radical form is an intermediate for the reductive glycosidic cleavage of anthracycline in bovine milk xanthine oxidase.
Abstract: Bovine milk xanthine oxidase (xanthine:oxidase oxygen oxidoreductase, EC [1.2.3.2][1]) utilizes anthracycline antibiotics including daunorubicin and adriamycin in its electron transfer system both aerobically and anaerobically and generates drug semiquinone free radicals. Under anaerobic conditions and in the presence of several electron donors, xanthine oxidase metabolizes daunorubicin and adriamycin. The resultant metabolite from daunorubicin was identified as 7-deoxydaunorubicin aglycone by chromatography and mass spectrometry. NADH is the preferred electron donor for the cleavage reaction, although xanthine, purine, and glycolaldehyde also function. The cleavage reaction has the highest activity in phosphate buffer with a wide optimal pH range. With NADH as electron donor the concentration that gave 50% of the maximum cleavage rate is 250 µM for daunorubicin. Oxygen consumption by xanthine oxidase was stimulated by anthracyclines when NADH and NADPH were the electron donors, but it was inhibited if other electron donors were used. Both cleavage reaction and oxygen uptake are inhibited by allopurinol. Daunorubicin semiquinone free radical ( g value, 2.0035 ± 0.0001) was detected by electron paramagnetic resonance after a lag period when xanthine oxidase was incubated with NADH or xanthine. The same free radical signal was detected without the lag period when the system was kept anaerobic. This lag period is precisely the time required for the depletion of oxygen as indicated by measuring the oxygen uptake. We propose that the semiquinone free radical form is an intermediate for the reductive glycosidic cleavage of anthracycline.
ACKNOWLEDGMENTS We thank Ms. Leslie Pedersen for the technical assistance. We also appreciate the help of Dr. Edward Chou and Mr. Paul Andrews for obtaining the mass spectra, Dr. William Caspary for the EPR spectra, and Ms. Helen Chiewicki in the preparation of the manuscript.
[1]: pending:yes
76 citations
TL;DR: Under rigorously anaerobic conditions, 3 to 4 mol of ferricyanide/active site were reduced, indicating that the molybdenum centers in the inactive enzyme had been reduced below the levels attained by the native enzyme during catalysis.
76 citations
TL;DR: Evidence is presented that t-butanol serves as a substrate for rat liver microsomes and that it is oxidatively demethylated to yield formaldehyde, and results indicate that t -butanol cannot be used to distinguish metabolically-linked from non-metabolically- linked actions of ethanol.
61 citations
TL;DR: In this article, the title compound chemiluminesces in aqueous solutions (pH 5−6.5) in the presence of xanthine-xanthine oxidase system; O2− and not 1O2 was proven to be the active species.
Abstract: The title compound chemiluminesces in aqueous solutions (pH 5–6.5) in the presence of xanthine–xanthine oxidase system; O2− and not 1O2 was proven to be the active species. Quantitative determination of xanthine and xanthine oxidase as low as 5 nmol and 10−5 unit, respectively, is possible by measurement of the chemiluminescence light yield and the reaction rate.
46 citations
TL;DR: The results show that the intestinal metabolism of dietary adenine is uniquely different from that of guanine, hypoxanthine or xanthine.
Abstract: One experiment was conducted in which radioactively labeled purine bases (adenine, guanine, hypoxanthine and xanthine) were individually given intravenously to young adult rats and the recovery of radioactivity in urine and gut, gut content and liver was measured at the end of the next 24 hours. The total recovery of radioactivity from orally and intravenously administered adenine was measured in experiment 2. A third experiment measured the recoveries of radioactivity from oral and intravenous adenine in a wider variety of tissues and organs than in experiment 1. The chemical identities of the urinary end products of the metabolism or orally and intravenously administered adenine were compared in a fourth experiment. When purines were given intravenously, significantly more of the administered radioactivity was recovered in urine from rats given guanine, hypoxanthine or xanthine compared with those given adenine. The greater recoveries of radioactivity in urine were associated with smaller recoveries in tissues. A larger proportion of intravenously compared to orally administered radioactivity from adenine was incorporated into all body tissues, and this was most pronounced in glandular and lymphoid tissues. The primary urinary end product of both orally and intravenously administered adenine was allantoin. The absorption of individual purines from isolated rat gut sacs was evaluated in a fifth experiment. A significant proportion of unaltered adenine crossed the mucosal to serosal barrier of intestinal sacs whereas unaltered guanine, hypoxanthine or xanthine did not cross into the serosal fluid. These results show that the intestinal metabolism of dietary adenine is uniquely different from that of guanine, hypoxanthine or xanthine.
44 citations
TL;DR: During microsomal electron transfer, conditions may be appropriate for a Fenton type or a modified Haber-Weiss type of reaction to occur, leading to the production of hydroxyl radicals.
Abstract: The microsomal oxidation of ethanol or 1-butanol was increased by ferrous ammonium sulfate-ethylenediaminetetraacetic acid (1:2) (Fe-EDTA) (3.4-50 microM). The increase was blocked by hydroxyl radical scavenging agents such as dimethyl sulfoxide or mannitol. The activities of aminopyrine demethylase or aniline hydroxylase were not affected by Fe-EDTA. The accumulation of H2O2 was decreased in the presence of Fe-EDTA, consistent with an increased utilization of H2O2. Other investigators have shown that Fe-EDTA increases the formation of hydroxyl radicals in systems where superoxide radicals are generated. The stimulation by Fe-EDTA appears to represent a pathway involving hydroxyl radicals rather than catalase because (1) stimulation occurred in the presence of azide, which inhibits catalase, (2) stimulation occurred in the presence of 1-butanol, which is not an effective substrate for catalase, and (3) stimulation was blocked by hydroxyl radical scavenging agents, which do not affect catalase-mediated oxidation of ethanol. A possible role for contaminating iron in the H2O or buffers could be ruled out since similar results were obtained with or without chelex-100 treatment of these solutions. The stimulatory effect by Fe-EDTA required microsomal electron transfer with NADPH, and H2O2 could not replace the NADPH-generating system. In the absence of microsomes or catalase, Fe-EDTA also stimulated the coupled oxidation of ethanol during the oxidation of xanthine by xanthine oxidase. These results suggest that during microsomal electrom transfer, conditions may be appropriate for a Fenton type or a modified Haber-Weiss type of reaction to occur, leading to the production of hydroxyl radicals.
TL;DR: There was a significant increase in xanthine levels in patients with gout and renal failure, or renal failure on allopurinol, and plasma levels of oxipur inol were increased, but no correlation with glomerular filtration rate (GFR) was observed.
TL;DR: The results support the existence of adenosine receptors in the guinea‐pig trachea and caffeine and theophylline enhanced the non‐adrenergic inhibitory response to nerve stimulation (NAIR).
Abstract: 1 To test the possibility that adenosine receptors exist within the trachea of the guinea-pig, an attempt has been made to identify a compound with adenosine antagonist activity in this tissue.
2 Quinidine, phentolamine, phenoxybenzamine, 2-2′-pyridylisatogen tosylate (PIT) and caffeine were tested for antagonism of spasmolytic responses to adenosine, adenosine 5′-triphosphate (ATP) and adenine on the guinea-pig isolated trachea.
3 Quinidine (10 and 25 μg/ml), phentolamine (10 and 30 μg/ml) and phenoxybenzamine (10 μg/ml) had little or no effect on response to adenosine, ATP and adenine. PIT (21 μg/ml) potentiated responses to adenosine, ATP and adenine by an unexplained mechanism.
4 Caffeine (25 μg/ml) partially relaxed the trachea and inhibited spasmolytic responses to both adenosine and ATP, but not to adenine, isoprenaline, aminophylline or prostaglandin E2 (PGE2).
5 A number of compounds related to caffeine (xanthine, hypoxanthine, theophylline and theobromine) were tested for adenosine antagonist activity. Xanthine (300 μg/ml) and hypoxanthine (300 μg/ml) did not relax the trachea or antagonize spasmolytic responses to adenosine. Both theophylline (10 μg/ml) and theobromine (30 μg/ml) partially relaxed the trachea; theophylline, but not theobromine, antagonized spasmolytic responses to adenosine.
6 pA2 values for caffeine and theophylline as antagonists of adenosine were 4.3 and 4.7 respectively. However, the slopes of the Schild plot regressions were significantly less than 1.0 for both compounds.
7 Four compounds, adenine, AH 8883, M30966 and ICI 63197, which like caffeine and theophylline, have phosphodiesterase inhibitory activity were tested for adenosine antagonist activity in the trachea. Adenine and AH 8883 had no effect and M30966 and ICI 63197 caused significant potentiation.
8 The effects of caffeine and theophylline were also investigated on the non-adrenergic inhibitory response to nerve stimulation (NAIR). Both caffeine (100 μg/ml, n = 4) and theophylline (30 μg/ml, n = 4) enhanced the NAIR (20 Hz) while virtually abolishing matched responses to exogenous adenosine.
9 The results support the existence of adenosine receptors in the guinea-pig trachea.
TL;DR: Ureide synthesis was confined to soluble extracts from the bacteroid-containing tissue, was stimulated by pyridine nucleotides and intermediates of the pathways of aerobic oxidation of ureides, but was completely inhibited by allopurinol, a potent inhibitor of xanthine dehydrogenase.
Abstract: The synthesis of 14C-labeled xanthine/hypoxanthine, uric acid, allantoin, allantoic acid, and urea from [8-14C]guanine or [8-14C]hypoxanthine, but not from [8-14C]adenine, was demonstrated in a cell-free extract from N2-fixing nodules of cowpea (Walp.). The 14C recovered in the acid/neutral fraction was present predominantly in uric acid and allantoin (88-97%), with less than 10% of the 14C in allantoic acid and urea. Time courses of labeling in the cell-free system suggested the sequence of synthesis from guanine to be uric acid, allantoin, and allantoic acid. Ureide synthesis was confined to soluble extracts from the bacteroid-containing tissue, was stimulated by pyridine nucleotides and intermediates of the pathways of aerobic oxidation of ureides, but was completely inhibited by allopurinol, a potent inhibitor of xanthine dehydrogenase (EC 1.2.1.37). The data indicated a purine-based pathway for ureide synthesis by cowpea nodules, and this suggestion is discussed.
TL;DR: Increased RNA synthesis in the protoplasts of tobacco leaf mesophyll resulted in enhanced incorporation of adenine and guanine, but not of hypoxanthine and adenosine, into the nucleic acid fraction.
Abstract: The overall metabolism of purines was studied in tobacco (Nicotiana tabacum) mesophyll protoplasts Metabolic pathways were studied by measuring the conversion of radioactive adenine, adenosine, hypoxanthine and guanine into purine ribonucleotides, ribonucleosides, bases and nucleic acid constituents Adenine was extensively deaminated to hypoxanthine, whereupon it was also converted into AMP and incorporated into nucleic acids Adenosine was mainly hydrolysed to adenine Inosinate formed from hypoxanthine was converted into AMP and GMP, which were then catabolized to adenine and guanosine respectively Guanine was mainly deaminated to xanthine and also incorporated into nucleic acids via GTP Increased RNA synthesis in the protoplasts resulted in enhanced incorporation of adenine and guanine, but not of hypoxanthine and adenosine, into the nucleic acid fraction The overall pattern of purine-nucleotide metabolic pathways in protoplasts of tobacco leaf mesophyll is proposed
TL;DR: Serum creatinine, uric acid, and hypoxanthine and xanthine concentrations were determined in 17 mother-infant pairs at the time of delivery andCorrelations of the excreted substances to each other were calculated.
Abstract: Serum creatinine, uric acid, and hypoxanthine and xanthine concentrations were determined in 17 mother-infant pairs at the time of delivery. Creatinine and uric acid levels were nearly similar, but hypoxanthine and xanthine were more than twice as high in the blood of the infants than in the blood of their mothers. In the same newborns the urinary excretion of creatinine, uric acid, hypoxanthine and xanthine, uracil, cAMP, and cGMP was measured on the first and fourth day of life. Creatinine, uracil, and cAMP increased, hypoxanthine and xanthine, and cGMP decreased, whereas the output of uric acid was nearly the same on both days. Correlations of the excreted substances to each other were calculated.
TL;DR: In this paper, the effect of oxidant stress on human lymphocyte cytotoxicity was studied and it was shown that the impairment of lymphocyte function that resulted from the in vitro exposure to the Xanthine and xanthine oxidase was mediated primarily through the generation of hydrogen peroxide.
Journal Article•
TL;DR: The nitrate and nitrite reductase activities of milk xanthine oxidases were studied and the optimal conditions for manifestation of these activities were found.
Abstract: The nitrate and nitrite reductase activities of milk xanthine oxidases were studied. The optimal conditions for manifestation of these activities were found. A possible mechanism of electron transport to nitrate and nitrite inside the enzyme is discussed.
TL;DR: The sera of 30 healthy male beagles were analyzed by reversed-phase high-performance liquid chromatography and the chromatograms of each group were very reproducible; however, there were characteristic differences between the two groups.
TL;DR: Uricase activity was found in Enterobacter cloacae KY3074 grown on guanine, hypoxanthine, uric acid, and xanthine media, and the activity was inhibited by the presence of potassium cyanide, Ag+ or Cu2+.
Abstract: Uricase activity was found in Enterobacter cloacae KY3074 grown on guanine, hypoxanthine, uric acid, and xanthine media. The enzyme was purified from cells grown on uric acid as a source of nitrogen. The purification procedure included ammonium sulfate fractionation, gel filtration on Sephadex G-150, and column chromatography on DEAE-cellulose and DEAE-Sephadex. The enzyme had a molecular weight of about 105,000 and was specific for uric acid. The optimum pH was around 9.5, and the activity was inhibited by the presence of potassium cyanide, Ag+ or Cu2+. This uricase can be used for estimation of uric acid.
01 Jan 1980
TL;DR: The sulfite oxidase as discussed by the authors is an enzyme that catalyzes the conversion of sulfite to sulfate in animal tissues by using free-radical chain reactions initiated by superoxide anions generated by xanthine oxidase.
Abstract: Publisher Summary The enzymatic oxidation of sulfite to sulfate has been demonstrated in animal tissues by researchers. The enzyme catalyzing the conversion of sulfite to sulfate has been termed sulfite oxidase. The oxidation of sulfite by the enzyme is efficient even at very low concentrations of substrate, occurs in the presence of electron acceptors other than oxygen, and is unaffected by the presence of free radical scavenging agents. These criteria distinguish the enzyme-catalyzed reaction from nonenzymatic aerobic sulfite oxidation that proceeds by a metal-catalyzed free-radical mechanism, requires high concentrations of sulfite and oxygen, and is inhibited by free radical scavengers. A pseudo-enzymatic mechanism of sulfite oxidation occurs when sulfite is present during the aerobic oxidation of hypoxanthine, xanthine, or other substrates by milk xanthine oxidase. The oxidation of sulfite in this system is by free-radical chain reactions initiated by superoxide anions generated by xanthine oxidase in the course of electron transfer to O2.
TL;DR: It appears that the increased loss of oxypurines in HPI is caused by the impact of hypoxia, probably owing to be compromised cellular respiration with a subsequent general displacement of the purine metabolism in the catabolic direction.
Abstract: The daily urinary excretion of the oxypurines hypoxanthine, xanthine and uric acid during each of the first 3 days of life was determined in premature infants without hypoxia (PI) and in hypoxic premature infants (HPI) with the respiratory distress syndrome. The loss of uric acid was statistically significantly greater in the HPI during days 1, 2, and 3 of life, and so was the loss of xanthine on days 1, and 2, but not on day 3. As to the loss of hypoxanthine, no difference could be shown. In both groups of infants the excretion of hypoxanthine and xanthine together made up about 2% of the total oxypurine loss for each day, the loss of xanthine being the greater of the two. The results did not seem to bear relation to differences between the two groups concerning urinary output, birth weight, gestational age, method of delivery, or administration of exogenic purines. So it appears that the increased loss of oxypurines in HPI is caused by the impact of hypoxia, probably owing to the compromised cellular respiration with a subsequent general displacement of the purine metabolism in the catabolic direction.
TL;DR: The method presented for the simultaneous determination of xanthine and hypoxanthine, uses mass-fragmentography in the electron impact (EI) mode, after the gas chromatographic separation of butylated derivatives.
TL;DR: In xanthinuria, characterized by a gross deficiency of XO in the tissues it is not known whether the variations in the level of residual activity ofXO represent methodologic limitations or heterogeneity of the genetic and molecular defect.
Abstract: Xanthine oxidase (xanthine oxygen-oxidoreductase EC 1.2.3.2.) catalyses oxidation of hypoxanthine and xanthine to uric acid. In man, small intestines and liver are the only tissues that normally show abundant xanthine oxidase (XO) activity. But localization, level, form of catalytic activity and physiological function in the different tissues are not clearly known. In xanthinuria, characterized by a gross deficiency of XO in the tissues it is not known whether the variations in the level of residual activity of XO represent methodologic limitations or heterogeneity of the genetic and molecular defect.
TL;DR: The addition of prostaglandin E1 (10(-10)M) restores the inhibitory effect of insulin on cyclic AMP accumulation.
TL;DR: According to these resutls, the utilization of purine derivatives and of allantoin as sources of carbon and energy is repressed by adenine in cells of A. eutrophus H 16.
Abstract: With 0.5% substrate present in mineral medium, cells of Alcaligenes eutrophus H 16 were able to grow heterotrophically at the expense of guanine, hypoxanthine and xanthine, but not of adenine as sole sources of carbon and nitrogen. An increase in cell counts, however, was observed at lower adenine concentrations (0.1%). Similarly, adenine was only respired if present at low concentrations. Higher amounts of adenine were inhibitory to the utilization of adenine, guanine, hypoxanthine, xanthine, allantoin and glyoxylate, but not to that of fructose or glycerate. The adenine-dependent inhibition of adenine utilization was not overcome by the addition of thiamine, uridine or cytidine. The enzyme glyoxylate carboligase, usually formed in presence of metabolisable purines and of allantoin, was synthesized only at low adenine concentrations. Higher amounts were inhibitory even with allantoin present as additional substrate. According to these resutls, the utilization of purine derivatives and of allantoin as sources of carbon and energy is repressed by adenine in cells of A. eutrophus H 16.
TL;DR: The levels of four purine compounds (adenine, guanine, hypoxanthine, and xanthine) have been evaluated in some poultry products as mentioned in this paper, and the levels of all purines were relatively low in gizzard and mechanically deboned broiler tissues.
Abstract: The levels of four purine compounds (adenine, guanine, hypoxanthine, and xanthine) have been evaluated in some poultry products. The levels of total purines in light and dark meat were lower than what has been reported for other foods but the level of hypoxanthine was somewhat higher. In contrast, the level of total liver purines was higher than in other broiler tissues but the liver contained mostly adenine and guanine. The levels of all purines were relatively low in gizzard and mechanically deboned broiler tissues.
TL;DR: In vitro microbiocidal activity of the new antibody-enzyme conjugate, when incubated together with xanthine and minute amount of halides, showed a remarkable level of candidacidal ability.
Abstract: A new type of antibody-enzyme conjugate was made, and its possible application to Candida infection was studied. Both lactoperoxidase and xanthine oxidase were conjugated to specific antibody against Candida albicans. In vitro microbiocidal activity of the new antibody-enzyme conjugate, when incubated together with xanthine and minute amount of halides, showed a remarkable level of candidacidal ability. When the new antibody-enzyme conjugate was given to Candida-infected mice, followed by injecting xanthine and a minute amount of halides, about 50% of these heavily infected mice survived, whereas all control nontreated mice died. These data suggest that the further eleboration of this new antibody-enzyme conjugate might lead us to improve our therapeutic methods of clinical medicine.
TL;DR: None of the imidazole-sulfonamides or the purine 6-solfonyl analogues inhibited the growth of L1210 cells in culture nor were they substrates for or significant inhibitors of human hypoxanthine--guanine phosphoribosyltransferase or milk xanthine oxidase.
Abstract: Reduction of 4(5)-nitroimidazole-5(4)-sulfonamide afforded the sulfonamide analogue of 4(5)-aminoimidazole-5(4)-carboxamide (AICA). This was formylated to afford the sulfonamide analogue of formyl-AICA and was ring closed to the unsubstituted 6-sulfonyl analogue of guanine, 3-aminoimidazo[4,5-e]-1,2,4-thiadizine 1,1-dioxide. Diazotiz ation of the latter afforded the corresponding 6-sulfonyl analogue of xanthine. None of the imidazole-sulfonamides or the purine 6-sulfonyl analogues inhibited the growth of L1210 cells in culture nor were they substrates for or significant inhibitors of human hypoxanthine--guanine phosphoribosyltransferase or milk xanthine oxidase.
Patent•
18 Apr 1980
TL;DR: In this article, the substrate for xanthine oxidase is determined in one step by using the test composition for the determination of the substrate which comprises xanthines oxidase and a system for determination of hydrogen peroxide, and the determination method can be applied to the compound which participates in the system wherein the substrate is stoichiometrically formed by reaction or decomposition.
Abstract: The substrate for xanthine oxidase such as xanthine, hypoxanthine, guanine, 2-hydroxypurine, etc. are determined by oxidizing the substrate by the action of xanthine oxidase derived from a microorganism and determining the formed hydrogen peroxide by the system for the determination of hydrogen peroxide comprising peroxidase and coloring reagent. The determination is carried out in one step by using the test composition for the determination of the substrate for xanthine oxidase which comprises xanthine oxidase and a system for the determination of hydrogen peroxide. The determination method can be applied to the determination of the compound which participates in the system wherein the substrate is stoichiometrically formed by the reaction or decomposition. When the system is an enzymatic reaction, the compound is determined in one step. Xanthine oxidase used in the present invention is different from known xanthine oxidase in molecular weight and is prepared by culturing a microorganism belonging to the genus Enterobacter.