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

(1) The effect of feeding a relatively low-protein diet containing 0.06% DAB for 29 weeks on the activity of DAB-azoreductase, nitroreductase (p-nitrobenzoic acid), N-oxidase (N,N-dimethylaniline), N-demethylase (DAB), cytochrome P-450, NADPH-cytochrome c reductase, beta-glucuronidase and arylsulphatase A were studied. Rapid decreases occurred in the activities of the first six enzymes, reaching minimal values at between 4 and 8 weeks. Activities then increased in all cases to control or nearly control levels. This rate of increase was least for cytochrome P-450. At 4 weeks azoreductase activity with the chemotherapeutic agent CB10-252 (I) as substrate was significantly higher than in control rats. Early increases occurred in the activities of beta-glucuronidase and arylsulphatase A and the activity of the latter never dropped below the control level. (2) An investigation was made of the differential effects of dye feeding on some of the enzyme activities in the two major liver lobes and differences were found. (3) The effect of phenobarbital (PB) pretreatment on the DAB-fed rats was studied at 4-week intervals. The activities of DAB-azoreductase and of nitroreductase increased throughout the whole period, while the activities of the lysosomal enzymes were decreased. (4) After feeding DAB for 4 weeks the effect of PB and 3-methylcholanthrene (MC) on the activities of DAB-azoreductase, CB10-252-azoreductase and components of the azoreductases-cytochrome P-450, NADPH-cytochrome c reductase, the CO-CB10-252-azoreductase was not induced by PB or MC, and CO did not inhibit its reduction. Its reduction depended only slightly on NADH. CO caused a greater relative decrease in the activity of DAB-azoreductase in dye-fed animals and also in animals following PB and MC pretreatment, implying a greater role of cytochrome P-450 in dye-fed animals.
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PMID:The effects of the continuous administration of N,N-dimethyl-4-phenylazoaniline (DAB) on the activities and the inducibilities of some drug-metabolizing enzymes in rat liver. 0 Jan 48

Both UDP-glucuronyltransferase (GT) and beta-glucuronidase (betaG) were assayed in untreated liver microsomes. Optimum assay conditions were established with rat liver microsomes using p-nitrophenol (pNP) and its glucuronide (pNPGA) at the pH optima of GT (7.5) and betaG (4.5). The activities of the two enzymes were compared using microsomes from rats, mice, pigs, cattle and horses, with pNP, pNPGA, and phenolphthalein as substrate, in the presence of various cofactors and inhibitors at pH 7.5 and 4.5. These data disclose pronounced differences with respect to species, substrate and other experimental conditions, thereby precluding the establishment of general optimum conditions. The two enzymes were also assayed under strictly identical conditions using pNP and pNPGA and rat liver microsomes at pH 7.5 in the presence and absence of UDP-glucuronate disodium (UDPGA), activators (ATP;UDP-N-acetylglucosamine) and inhibitors. When provided with a functional level of UDPGA, both enzymes proved active under those conditions, and a conjugation-deconjugation interplay was indicated. The two processes could be selectively and totally inhibited by Zn2+ and saccharolactone. The results suggest that conjugation-deconjugation-reconjugation cycles may be operative in the metabolism of drugs in vivo, taking place already at the level of the liver endoplasmic reticulum.
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PMID:Liver microsomal beta-glucuronidase and UDP-glucuronyltransferase. 0 Feb 30

The beige mouse is an animal model for the human Chediak-Higashi syndrome, a disease characterized by giant lysosomes in most cell types. In mice, treatment with androgenic hormones causes a 20-50-fold elevation in at least one kidney lysosomal enzyme, beta-glucuronidase. Beige mice treated with androgen had significantly higher kidney beta-glucuronidase, beta-galactosidase, and N-acetyl-beta-D-glucosaminidase (hexosaminidase) levels than normal mice. Other androgen-inducible enzymes and enzyme markers for the cytosol, mitochondria, and peroxisomes were not increased in kidney of beige mice. No significant lysosomal enzyme elevation was observed in five other organs of beige mice with or without androgen treatment, nor in kidneys of beige females not treated with androgen. Histochemical staining for glucuronidase together with subcellular fractionation showed that the higher glucuronidase content of beige mouse kidney is caused by a striking accumulation of giant glucuronidase-containing lysosomes in tubule cells near the corticomedullary boundary. In normal mice lysosomal enzymes are coordinately released into the lumen of the kidney tubules and appreciable amounts of lysosomal enzymes are present in the urine. Levels of urinary lysosomal enzymes are much lower in beige mice than in normal mice. It appears that lysosomes may accumulate in beige mice because of defective exocytosis resulting either from decreased intracellular motility of lysosomes or from their improper fusion with the plasma membrane. A similar defect could account for characteristics of the Chediak-Higashi syndrome.
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PMID:Defective lysosomal enzyme secretion in kidneys of Chediak-Higashi (beige) mice. 0 Apr 8

A technique utilizing Pregnant Mare's Serum Gonadotropin and Human Chorionic Gonadotropin treatment of hens (Gallus domesticus), followed by manual ovulation of the excised follicles, was developed to obtain a large number of mature ova. The intact ova were used to test whether acrosin, partially purified from the spermatozoa of the cock (Gallus domesticus), partially purified rabbit testicular acrosin and commercial preparations of several hydrolytic enzymes could dissolve the inner vitelline membrane. Enzymes were applied to pieces of filter paper placed on the ovum. Cock acrosin and endopeptidases such as trypsin, chymotrypsin, collagenase and elastase hydrolyzed the membrane whereas exopeptidases such as leucine aminopeptidase and carboxypeptidase A did not. Phospholipase A, sulfatase, hyaluronidase, beta-glucuronidase and rabbit testicular acrosin also failed to hydrolyze the membrane. Cock acrosin hydrolysis of the ovum surface was inhibited by soybean trypsin inhibitor. The surface of the ovum over the germinal disc region was hydrolyzed more quickly by cock acrosin than the surface over other regions of the ovum. Acrosin from cock sperm caused the release of trichloroacetic acid soluble material absorbing at 280 nm from sonicated preparations of inner vitelline membranes. Hydrolysis was greatest at pH 8.0 and was inhibited by soybean trypsin inhibitor.
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PMID:Hydrolysis of the hen egg vitelline membrane by cock sperm acrosin and other enzymes. 0 Apr 54

The purpose of the present study was to evaluate the properties of beta-glucuronidase (EC 3.2.1.31) in human synovial fluid. It was shown to have a pH requirement of 5.0 and a KM value of about 8.0 - 10(-3) M using phenolphthalein beta-glucuronide as the substrate. At low substrate concentration an endogenous inhibitor is demonstrable. The inhibition is of the competitive type and is removed by proteolytic digestion of synovial fluid, whereas hyaluronidase digestion and addition either of Triton X-100 or of various salts to the assay mixture, are ineffective. The possibility that the inhibitor is a protein from serum is discussed.
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PMID:Properties of beta-glucuronidase activity in human synovial fluid. 0 Nov 63

1. A radiochemical method for the studies on the microsomal UDPglucuronic acid metabolism has been developed. 2. The rat liver microsomes caused a rapid hydrolysis of UDPglucuronic acid to D-glucuronic acid 1-phosphate and further although much slower to free D-glucuronic acid. In Tris-HCl buffer (pH 7.4) they were produced in ratio 72 : 1. No other metabolites were found in measurable amounts. The pyrophosphatase splitting UDPglucuronic acid showed a pH optimum at 8.9, but the liberation of D-glucuronic acid from UDPglucuronic acid had two pH maxima (pH 3.5 and 8.5). EDTA appeared to be less powerful inhibitor of pyrophosphatase than previously suggested. About 25 per cent of the UDPglucuronic acid hydrolyzing activity was still remaining in the presence of 10 mM EDTA. D-Glucaro-1,4-lactone was found to have a slight inhibitory action on the pyrophosphatase activity. Citrate inhibited powerfully the hydrolysis of UDPglucuronic acid and the liberation of free D-glucuronic acid. Phosphate was also inhibitory. 3. In the presence of an exogenous UDPglucuronosyltransferase substrate, 4-nitrophenol, the formation of D-glucuronic acid 1-phosphate and free D-glucuronic acid were slightly reduced, and D-glucuronic acid 1-phosphate, 4-nitrophenylglucuronide and free D-glucuronic acid were produced in ratio 78 : 23 : 1. When 10 mM EDTA was added to diminish the hydrolytic consumption of the glucuronyl donor substrate, the corresponding ratio was still as unfavorable as 19 : 2.6 : 1. The measurable activity of UDPglucuronosyltransferase was lower in the presence of phosphate or citrate than in Tris-HCl buffer, although they protected the glucuronyl donor substrate against hydrolysis. 4. The results indicate that even in the presence of added glucuronyl acceptor substrate the hydrolysis of UDPglucuronic acid predominates the conjugation in rat liver microsomes. The rate of the hydrolysis of UDPglucuronic acid is quite considerable even in the presence of EDTA, and it is recommended to control the UDPglucuronic acid pyrophosphatase activity when UDPglucuronosyltransferase and glucuronidation reactions are studied. Free D-glucuronic acid appears to be produced from UDPglucuronic acid for further use via D-glucuronic acid 1-phosphate, the rate-limiting step being the hydrolysis of this intermediate. UDP-glucuronosyltransferase, glucuronides of either endogenous or exogenous aglycones and beta-glucuronidase have only a minor role in this respect in rat liver microsomes.
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PMID:Pyrophosphatase and glucuronosyltransferase in microsomal UDPglucuronic-acid metabolism in the rat liver. 0 Dec 76

The levels of six lysosomal enzymes (acid phosphatase, beta-acetylglucosaminidase, cathepsin D, beta-galactosidase, arylsulfatase A, and beta-glucuronidase) and four neutral and alkaline hydrolases (esterase, inorganic phyrophosphatase, alkaline phosphatase, and 5'-nucleotidase) were measured in osteoarthritic, rheumatoid and control synovia. All enzyme levels in diseased synovium except esterase values in osteoarthritis were significantly elevated compared with controls. The mean values of the group of acid hydrolases and the group of neutral and alkaline hydrolases in osteoarthritic synovia were 1.9- and 2.0-fold greater than those of control specimens. In rheumatoid synovia, the values were 4.2- and 4.5 fold greater than control for the same enzymes. Levels in rheumatoid synovia were significantly higher than those in osteoarthritic synovia with the exception of 5'-nucleotidase. Only a limited correlation between the extents of inflammation present in the synovia and the levels of a lysosomal marker enzyme (cathepsin D) was observed. These results demonstrate that whatever the mechanism, increased levels of acid hydrolases as well as certain neutral and alkaline hydrolases are present in osteoarthritic and rheumatoid synovia, and these enzymes are probably contained in the synovial lining cells.
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PMID:Acid, neutral, and alkaline hydrolases in arthritic synovium. 0 9

Lymphocytes, monocytes, neutrophilic granulocytes and platelets were each separated to greater than 95% purity from six normal subjects, three patients with Gaucher's disease, two heterozygotes for Gaucher's disease, and one patient with Fabry's disease. Activities of the following acid hydrolases were determined: "acid" (pH 4.0) beta-glucosidase, pH 5.0 beta-glucosidase, alpha-galactosidase, alpha-arabinosidase, alpha-mannosidase, alpha-glucosidase, beta-glucuronidase, beta-galactosidase, beta-hexosaminidase, and acid phosphatase. Enzymatic activity varied greatly with cell type and the enzyme being measured; the importance of assaying pure preparations especially for heterozygote detection is emphasized. Gaucher's disease patients' cells were found to be deficient in the pH 4.0 acid beta-glucosidase, variable in the pH 5.0 beta-glucosidase, and normal in all other acid hydrolases tested, including acid phosphatase, the activity of which is known to be elevated in plasma. Blood cells of a patient with Fabry's disease were deficient in alpha-galactosidase and normal in all other acid hydrolases tested.
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PMID:Acid hydrolases in leukocytes and platelets of normal subjects and in patients with Gaucher's and Fabry's disease. 0 20

The effect of 120- and 240-h starvation on rats hepatocytes ultrastructure and particularly the changes of the lysosomes were studied. Eelectronmicroscopically and cytochemically there have been observed diminution of the number of mitochondria and degranulation and vacuolzation of the ER. At the same time Golgi complex was hypertrophied and the number of lysosomes was much increased, mainly those of the autophagic type. Biochemically was shown, that the activity of some acid hydrolases (beta-glucosidase, alpha- and beta-galactosidases, beta-N-acetylglucosaminidase, beta-glucuronidase and arylsulphatases A and B) in the liver of starved rats was markedly expressed. The sedimentation properties of the lysosomes and the lysosomal membrane stability was damaged as well. The data received have been discussed in the light of the reconstructive role of lysosomes.
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PMID:Effect of long-term starvation on the rat liver lysosomes. 0 4

After 24-hr exposures of rainbow trout to 0.5 ppm of di-2-ethylhexyl [14C]phthalate, one-half of the radioactivity present in the fish was localized in the bile. The bile was pooled and fractionated by selective solvent extraction before and after beta-glucuronidase hydrolysis. Individual radioactive compounds were further separated and characterized by thin-layer chromatography. Gas chromatography-mass spectrometry was used to confirm the results of thin-layer chromatographic analysis. These procedures demonstrated that bile contained a number of DEHP metabolites, but only about 1% of unchanged DEHP. The major metabolite, mono-2-ethylhexyl phthalate glucuronide accounted for 72% of the total bile radioactivity. The remaining bile radioactivity was found to be present as phthalic acid glucuronide, mono-2-ethylhexyl phthalate and two partially characterized polar metabolites.
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PMID:Distribution and biliary excretion products of di-2-ethylhexyl phthalate in rainbow trout. 0 54


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