Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.31 (beta-glucuronidase)
 7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Open thyroid follicles were prepared by mechanical disruption of pig thyroid fragments through a metal sieve. This procedure allowed preparation of thyroid-cell material depleted of colloid thyroglobulin. Open thyroid follicles were used to prepared a crude particulate fraction, which contained lysosomes, mitochondria and endoplasmic reticulum. These organelles were subfractionated by isopycnic centrifugation on iso-osmotic Percoll gradients. A lysosomal peak was identified by its content of acid hydrolases: acid phosphatase, cathepsin D, beta-galactosidase and beta-glucuronidase. The lysosomal peak was well separated from mitochondria and endoplasmic reticulum. The lysosomal peak, from which Percoll was removed by centrifugation, was taken as the purified lysosome fraction (L). Lysosomes of fraction L were purified 45-55-fold (as compared with the homogenate) and contained about 5% of the total thyroid acid hydrolase activities. Electron microscopy showed that fraction L was composed of an approx. 90% pure population of lysosomes, with an average diameter of 220 nm. Acid hydrolase activities were almost completely (80-90%) released by an osmotic-pressure-dependent lysis. Thyroglobulin was identified by polyacrylamide-gel electrophoresis as a soluble component of the lysosome fraction. In conclusion, a 50-fold purification of pig thyroid lysosomes was achieved by using a new tissue-disruption procedure and isopycnic centrifugation on Percoll gradient. The presence of thyroglobulin indicates that the lysosome population is probably composed of primary and secondary lysosomes. Isolated thyroid lysosomes should serve as an interesting model to study the reactions whereby thyroid hormones are generated from thyroglobulin and released into the thyroid cells.
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PMID:Isolation of pig thyroid lysosomes. Biochemical and morphological characterization. 300 8

Serum amyloid P component (SAP) is a normal human serum protein with pentraxin structure that has morphological and immunochemical identity to the amyloid P component found in normal tissue and amyloid deposits. In the presence of calcium, SAP binds to certain complex polysaccharides, including agarose and zymosan. While the binding of SAP to agarose involves interaction with a galactose pyruvate acetal, the ligand in zymosan has not been defined. In the present study we determined that SAP binds to ligand(s) in a soluble extract of zymosan prepared by alkaline hydrolysis, which contains the mannose oligosaccharide sequences alpha DMan1----3DMan and alpha DMan1----6DMan. SAP did not bind to the alkali-insoluble fraction of zymosan, which is predominantly a glucan polymer, and its binding to zymosan extract which had been absorbed with concanavalin A was markedly reduced, suggesting that mannose residues are involved in the binding of SAP to zymosan. We also demonstrated that SAP binds to the glycoproteins ovalbumin, thyroglobulin, beta-glucuronidase and C3bi, which contain mannose-terminated sequences, while it did not bind to native and desialized preparations of ovomucoid, alpha 1-acid glycoprotein and glycophorin, which lack terminal mannose residues. SAP did not bind to pneumococcal C polysaccharide or to N-acetylglucosamine oligosaccharides covalently linked to a protein carrier. The binding of SAP to ligand(s) in zymosan extract or ovalbumin was inhibited by the preincubation of SAP with either zymosan extract or ovalbumin glycopeptides, both of which share similar mannose oligosaccharide sequences. All of the SAP binding reactions required calcium, were maximal at approximately 1 mM calcium, and gave similar results whether purified SAP or SAP in serum was used. These findings indicate that mannose-terminated oligosaccharides of polysaccharides and glycoproteins represent a new class of ligands for SAP and suggest that SAP may function as a mannose-binding protein.
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PMID:Evidence that serum amyloid P component binds to mannose-terminated sequences of polysaccharides and glycoproteins. 321 Nov 59

A benztropine RIA based on polyclonal antisera raised in New Zealand white rabbits has been developed. The drug-protein conjugates employed had a variety of moles of benztropine hemisuccinate coupled per mole of protein (bovine serum albumin or bovine thyroglobulin). Six antisera were developed and the one with the highest titer was further evaluated for its cross reactivity to N-desmethylbenztropine (4%) and the antipsychotic agents fluphenazine, flupenthixol, chlorpromazine, and haloperidol (all < 1%). The selected antiserum demonstrated sufficient sensitivity to measure benztropine from 0.156 to 100 ng/mL plasma in a 200-microL plasma sample, with a mean CV of < 6%. The RIA was applied to the analysis of steady-state plasma samples obtained from patients undergoing treatment with benztropine and plasma samples obtained from human volunteers and dogs orally dosed with the drug. Both the human and dog plasma samples, when analyzed after hydrolysis with beta-glucuronidase/sulfatase, demonstrated increments in benztropine concentrations, suggesting the drug may be undergoing biotransformation to phase II metabolite(s). In addition, when benztropine was selectively extracted from the unhydrolyzed plasma samples, there was a significant decrease in drug level, which further suggested that the antiserum cross reacted with phase II metabolite(s). The shape of the plasma concentration versus time profile obtained from the dog studies suggested that the drug might also undergo enterohepatic recycling.
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PMID:Development of a sensitive and specific radioimmunoassay for benztropine. 825 87

Immunoassays for the measurement of glucuronides in human urine can be a helpful tool for the assessment of human exposure to toxic chemicals. Therefore an enzyme imimunoassay (EIA) for the specific detection of phenyl-beta-D-thioglucuronide was developed. The immunoconjugate was formed by coupling p-aminophenyl-beta-D-thioglucuronide to the carrier protein thyroglobulin leaving an exposed glucuronic acid. The hapten-protein conjugate was adsorbed to gold colloids in order to enhance the immunogenic effect. Rabbits were injected with the immunogold conjugates to raise polyclonal antibodies. The resulting competitive assay showed an inhibition by phenyl-beta-D-thioglucuronide at sample concentrations of 23.0 +/- 1.3 ng/mL (50% B/B0) and a high cross-reactivity to p-aminophenyl-beta-D-thioglucuronide (120%). Little cross-reactivities (< 2%) were observed for potential urinary cross reactants. In addition human urine samples were incubated with beta-glucuronidase in order to investigate the EIA for specific matrix effects. An integration of high-performance liquid chromatography (HPLC) and EIA was developed in an attempt to decrease the matrix effects and increase the sensitivity of the overall method. The hyphenated technique HPLC-EIA may be used to monitor human exposure to toxic thiophenol which is excreted by mammals as urinary phenyl thioglucuronide.
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PMID:Development of a sensitive enzyme immunoassay for the detection of phenyl-beta-D-thioglucuronide in human urine. 1129 4