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:3.1.6.1 (sulfatase)
3,205 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The synthesis of N-hydroxyacetaminophen (N-acetyl-N-hydroxy-p-aminophenol, 4), a postulated toxic metabolite of acetaminophen (N-acetyl-p-aminophenol, 3), and its phenolic sulfate conjugate (potassium N-acetyl-N-hydroxy-p-aminophenyl sulfate) (13) is described. Potassium p-nitrophenyl sulfate was reduced to the hydroxylamine, acetylated, and treated with sulfatase to yield N-hydroxyacetaminophen. The structures assigned are supported by the spectral data (IR, UV, MS, 1H NMR, and 13C NMR). N-Hydroxyacetaminophen was found to be moderately unstable at physiological pH and temperature, whereas it phenolic sulfate conjugate was stable.
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PMID:Synthesis of N-hydroxyacetaminophen, a postulated toxic metabolite of acetaminophen, and its phenolic sulfate conjugate. 2 35

The metabolism of KC-764 (2-methyl-3-(1,4,5,6-tetrahydronicotinoyl)pyrazolo[1,5-a]pyridine, CAS 94457-09-7) in rat, rabbit and dog was studied. The urine of animals dosed with 14C-KC-764 was extracted with ethyl acetate after treatment with beta-glucuronidase and arylsulfatase. The metabolites were purified by TLC and HPLC from the extract. Unchanged KC-764 and 16 metabolites were isolated and their structures were identified or proposed by NMR and MS spectrometry. The metabolism of KC-764 took place by the oxidation of the tetrahydropyridine ring, 6,7-position and 2-methyl group of the pyrazolopyridine ring, and their combinations. The oxidation of the tetrahydropyridine ring was predominant in dog, whereas the oxidation of the pyrazolopyridine ring was more important in rabbit. Rat produced the various metabolites by their combination. 6-Oxo and 6-ureido derivatives of the tetrahydropyridine ring were common major metabolites in all animal species studied.
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PMID:Identification of urinary metabolites of 2-methyl-3-(1,4,5,6-tetrahydronicotinoyl)pyrazolo[1,5-a]pyridine in rat, rabbit and dog. 158 80

After ip administration of 3-tert-butyl-4-hydroxyanisole (3-BHA) to rats, two previously undocumented metabolites 2-tert-butyl-5-methylthiohydroquinone (TBHQ-5-SMe) and 2-tert-butyl-6-methylthiohydroquinone (TBHQ-6-SMe) were identified in the urine by comparison with the authentic samples by GC/MS. In addition to these metabolites, 3-tert-butyl-4,5-dihydroxyanisole was also detected in the urine hydrolyzed by beta-glucuronidase/sulfatase. Administration of tert-butylhydroquinone (TBHQ), an O-demethylated metabolite of 3-BHA, also resulted in the formation of the S-containing metabolites, TBHQ-5-SMe and TBHQ-6-SMe. After incubation of TBHQ with rat liver microsomes in the presence of glutathione (GSH), two metabolites were isolated and purified by HPLC. The metabolites were identified as 2-tert-butyl-5-(glutathion-S-yl)hydroquinone and 2-tert-butyl-6-(glutathion-S-yl)hydroquinone by 1H- and 13C-NMR spectrometry and by fast atom bombardment-mass spectrometry. The formation of TBHQ-GSH conjugates required NADPH, molecular oxygen, and GSH. Cytochrome P-450 inhibitors such as SKF 525-A and metyrapone markedly inhibited the formation of TBHQ-GSH conjugates in vitro. These results suggest that TBHQ is converted by cytochrome P-450-mediated monooxygenases to a reactive metabolite, 2-tert-butyl-p-benzoquinone (TBQ), which then conjugates with GSH to form TBHQ-GSH conjugates. GSH S-transferase activities do not seem to play a role in GSH conjugation reaction to TBQ because cytosol fraction from rat liver homogenates did not enhance the microsome-mediated production of TBHQ-GSH conjugates.
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PMID:Identification and structure characterization of S-containing metabolites of 3-tert-butyl-4-hydroxyanisole in rat urine and liver microsomes. 168 7

Metabolism of the antiarrhythmic drug encainide was studied in human subjects after a single 50-mg oral dose. Encainide labeled on the carbonyl carbon with 14C and at the benzylic (2'-1-ethyl) carbon with 13C was administered to four normal healthy male subjects. A large proportion of the radioactive dose (42%) was excreted in the urine in the first 24 hr. The total urinary excretion was 47.0 +/- 4.6% and total fecal excretion was 38.7 +/- 5.7% over 5 days. The conjugated metabolites excreted in the urine were hydrolyzed with beta-glucuronidase/arylsulfatase, and were isolated and purified by HPLC. Structural characterization was carried out by a combination of fast atom bombardment-mass spectrometry, gas chromatography/electron impact mass spectrometry, and 1H-NMR spectroscopy. Structures of the metabolites were confirmed by co-elution on HPLC with authentic standards when available. Six metabolites of encainide were identified from the hydrolyzed urine together with unchanged drug. In addition to already known metabolites O-demethyl-encainide, 3-methoxy-O-demethyl-encainide, and N,O-di-demethyl-encainide, three new metabolites were identified: N-demethyl-3-methoxy-O-demethyl-encainide, 3-hydroxy-encainide, and O-demethyl-encainide-lactam. These metabolites accounted for greater than 90% of the radioactivity excreted in the urine. Four major routes of metabolism were identified: first, O-demethylation of the aromatic methyl ether; second, formation of methylated catechol derivatives; third, N-demethylation of the piperidyl nitrogen; and fourth, oxidation at carbon alpha to the piperidyl nitrogen. A plausible scheme for the metabolism of encainide in human subjects is proposed.
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PMID:Structural characterization of urinary metabolites of the antiarrhythmic drug encainide in human subjects. 197 Jul 74

Following analysis by reversed-phase HPLC, a previously uncharacterized metabolite of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) was found in the urine of A/J mice treated with NNK. Treatment with beta-glucuronidase converted the metabolite to a peak that co-eluted with 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL). Treatment with sulfatase or beta-glucuronidase plus saccharic acid 1,4-lactone did not change the retention time of the metabolite. These data suggested that the unknown metabolite was a glucuronic acid conjugate of NNAL. Upon isolation and purification of larger quantities of the metabolite from the urine of A/J mice, CD-1 mice and F344 rats, 1H and 13C NMR and MS confirmed that the unknown metabolite was 4-(methylnitrosamino)-1-(3-pyridyl)-1-butyl beta-D-glucopyranosiduronic acid (NNAL Glu). To determine the quantitative relationship between NNK dose and NNAL Glu production and to compare the importance of glucuronidation relative to other metabolic pathways, [5-3H]NNK was administered to F344 rats and A/J mice at doses of 500-0.005 mumol/kg. At 500 mumol/kg, NNAL Glu accounted for 22% of the total urinary excretion of NNK in A/J mice, and for 8% in F344 rats 48 h after dosing. The proportions of excreted glucuronide and NNAL decreased with diminishing doses of NNK, yielding undetectable levels of each metabolite in both mice and rats at a dose of 0.005 mumol/kg NNK. Since substantial amounts of metabolites formed via alpha-hydroxylation and N-oxidation pathways were observed at the lower doses of NNK, these data demonstrate that NNAL glucuronidation is a quantitatively unimportant metabolic pathway at low doses of NNK.
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PMID:Characterization of a glucuronide metabolite of 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and its dose-dependent excretion in the urine of mice and rats. 220 95

Both isomers of epinephrine sulfate were synthesized, unequivocally identified by 1H-NMR and highly purified from catecholamines (less than 90 ppm). Bacterial as well as pig liver arylsulfatase A and B demonstrated a higher substrate turnover of epinephrine-4-sulfate, norepinephrine-4-sulfate and dopamine-4-sulfate as compared to the 3-sulfate isomers. The arylsulfatase B however, is less important for the deconjugation of these sulfoconjugates than arylsulfatase A. Since arylsulfatase A occurs in most human tissues, it might be of physiological significance in the deconjugation of the catecholamine sulfate isomers. Furthermore the kinetic data at pH 7.4 and 6.9 suggest the increased cleavage of the sulfate group, e.g. during exercise-induced acidosis. In contrast to results reported in the literature, dopamine sulfates were no substrates of dopamine beta-hydroxylase.
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PMID:Isomer specific kinetics of dopamine beta-hydroxylase and arylsulfatase towards catecholamine sulfates. 231 15

The metabolism of an orally administered, 10-mg single dose of the antianxiety drug buspirone was studied in the rat. Samples of bile and urine were collected for 6 hr and were treated with beta-glucuronidase/arylsulfatase. The deconjugated metabolites were isolated and purified by HPLC. Structural analysis was carried out by combined gas chromatography/electron impact mass spectrometry as their trimethylsilyl derivatives and by 1H-NMR spectroscopy. Structures of the metabolites were further confirmed by co-elution on HPLC with authentic standards when possible. In addition to the already known metabolites 5-hydroxy-buspirone and 1-pyrimidinylpiperazine, seven major metabolites were unambiguously identified together with unchanged drug. Ten minor metabolites were partially characterized. Hydroxylation alpha to the glutaramidyl carbon at the 6'-position on the bicyclo ring system, hydroxylation on the pyrimidine aromatic ring, and N-dealkylation of the butyl side chain were observed as major routes of metabolism. Minor routes of metabolism observed were: 3'-hydroxylation on the bicyclo ring system and formation of the methylated catechol derivatives. The identified metabolites accounted for greater than 90% of the total metabolites excreted in the rat bile and urine samples.
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PMID:Metabolism of the antianxiety drug buspirone in the rat. 257 98

The metabolism of an oral dose (20 mg) of the antianxiety drug buspirone labeled with 14C/15N was studied in human subjects. 15N was incorporated in the molecule to facilitate structural characterization of the metabolites by mass spectrometry. Urine samples were collected at intervals up to 24 hr and analyzed for radioactivity. Cumulative urinary excretion accounted for 50% of the dose in 24 hr. The urine was hydrolyzed with beta-glucuronidase/arylsulfatase and the deconjugated metabolites were isolated and purified by HPLC. The purified metabolites were identified by GC/MS, 1H-NMR, and comparison with authentic standards when available. Seven metabolites of buspirone were identified unambiguously, together with unchanged drug. Hydroxylation alpha to the glutarimidyl carbonyl at the 6'-position on the spiro ring system, hydroxylation at the 5-position on the pyrimidine ring, and N-dealkylation of the butyl-substituted side chain were major routes of metabolism. The identified metabolites accounted for 88% of the total radioactivity in the urine. A scheme for metabolism of buspirone in human subjects has been proposed.
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PMID:Metabolism of the antianxiety drug buspirone in human subjects. 257 99

Isolated rat hepatocytes (4 X 10(6) cells/ml metabolized the food mutagen 2-amino-1-methyl-6-phenylimidazo[4,5-b]-pyridine (PhIP) (100 microM) to at least eight different metabolites in a 4 h duration. The major metabolite formed was 4-(2-amino-1-methylimidazo[4,5-b]pyrid-6-yl)phenyl sulfate (4'-PhIP sulfate). Its rate of formation was increased in hepatocytes from PCB pretreated animals in comparison to hepatocytes from untreated animals. One of the other metabolites was the unconjugated derivative of the sulfate (4'-OH-PhIP). This metabolite was also found after in-vitro incubations of rat liver microsomes from PCB or beta-naphthoflavone pretreated animals. The evidence for the proposed structure of the major metabolite is based on [1H]NMR and UV spectroscopy, incorporation of radiolabelled sulfate and arylsulfatase-lability. The formation of 4'-PhIP sulfate was inhibited by the P-450 inhibitors alpha-naphthoflavone and metyrapone and when incubated in sulfate-free medium added the sulfotransferase inhibitor pentachlorophenol. 4'-PhIP sulfate was also the major metabolite of PhIP in the urine of exposed rat.
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PMID:4-(2-amino-1-methylimidazo[4,5-b]pyrid-6-yl)phenyl sulfate--a major metabolite of the food mutagen 2-amino-1-methyl-6- phenylimidazo[4,5-b]pyridine (PhIP) in the rat. 275 29

Metaproterenol (1-(3,5-dihydroxyphenyl)-2-isopropylaminoethanol) is primarily converted in humans to metaproterenol-3-O-sulfate following oral administration. Ion exchange column chromatography with a gradient of ammonium acetate buffer permitted the isolation of the ammonium salt of metaproterenol-3-O-sulfate from human urine. Treatment of aliquots of the column eluate with purified sulfatase and subsequent HPLC/fluorescence analysis confirmed the presence of metaproterenol. Comparison of the column eluate with a metaproterenol standard by 250-MHz proton-NMR revealed a pattern consistent with monosubstitution of the resorcinol ring. Negative and positive ion fast atom bombardment/mass spectrometry showed the metabolite to have a (M-H)- m/z of 290 and a (M + H)+ m/z ion of 292. These three methods support the structural assignment of metaproterenol-3-O-sulfate. Enzymatic hydrolysis of urine specimens from 29 different subjects with purified beta-glucuronidase as well as beta-glucuronidase-sulfatase mixtures yielded no significant increase in metaproterenol beyond purified sulfatase-treated urine, thus ruling out the presence of a glucuronide of metaproterenol. Approximately 40% of an oral 20-mg dose, given as either a tablet or a solution, was recovered in the urine as metaproterenol-3-O-sulfate. Approximately 5% of the dose was recovered in the unconjugated form. The majority of the dose was excreted over the first 12 hr with a biological half-life of 5-6 hr followed by a slower excretion phase with a half-life of 20 hr.
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PMID:Isolation and characterization of metaproterenol-3-O-sulfate: a conjugate of metaproterenol in human urine. 614 Jan 41


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