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:3.2.1.31 (beta-glucuronidase)
7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Peripheral blood monocytes isolated from patients with congenital hemolytic anemia, hereditary xerocytosis and spherocytosis, demonstrated in vivo engulfment of red cell and platelet fragments. In addition, morphometric studies performed on these monocytes showed an increase in cytoplasmic/nuclear ratio as well as lysosome and phagosome volumes. The production of carbon dioxide from glucose-1-14C in abnormal monocytes was increased (15-80%) but the intracellular values of beta-glucuronidase and esterase activity were similar to control monocytes. Monocyte locomotion assessed in the presence of chemotactic stimuli was found significantly increased (73 +/- 12 monocytes/oil immersion fields vs. 46 +/- 5 for control monocytes). We concluded that the monocytes in hemolytic anemias associated with increased in vitro red cell fragmentation have some features resembling the 'stimulated' monocytes and that this alteration may be due to red blood cell fragment ingestion.
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PMID:Characteristics of peripheral blood monocytes in hereditary xerocytosis and spherocytosis. 681 Jun 26

It has been shown that gold accumulates in macrophages. In vitro studies have also shown that long-term anti-inflammatory and immuno-regulatory effects on these cells may be responsible for the effectiveness of gold in the treatment of rheumatoid arthritis. However, the relevance of this information to the in vivo circumstance is largely untested. In this study, the effect of gold sodium thiomalate (AuTM) on rat alveolar macrophage (AM) lysosomal enzymes, bacterial killing, and metabolic activities associated with phagocytosis were assessed after in vivo administration. The activities of beta-glucuronidase, acid phosphatase, and lysozyme were inhibited 1 day following a single AuTM injection (50 mg/kg, subcutaneous). However, lysozyme returned to normal, while the activities of beta-glucuronidase and acid phosphatase were elevated from 4 to 12 days thereafter. When AuTM was administered weekly for 8 weeks, the activities of acid phosphatase and beta-glucuronidase were elevated throughout, while lysozyme was largely unaffected. The increased lysosomal enzyme activities were not due to contamination of polymorphonuclear leukocytes. These long-term effects of AuTm on enzyme activity were in marked contrast to its in vitro effect which inhibited the activities of beta-glucuronidase and acid phosphatase. No effect of AuTM administration on the release of beta-glucuronidase upon phagocytosis of opsonized zymosan was observed. At 1 day following a single AuTM injection or 3 days after a second weekly injection, in vivo bactericidal activity of AM toward S. aureus was diminished. This bacterial killing defect was not due to decrease phagocytosis; the in vivo binding and ingestion of bacteria were normal. The defect correlated with imparied metabolic activities associated with phagocytosis, namely a significant decrease in the reduction of nitroblue tetrazolium and the stimulation of the hexose monophosphate shunt. This may be an attractive anti-inflammatory effect in light of the destructive potential of the reactive oxygen species produced by macrophages in an arthritic circumstance.
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PMID:Effect of in vivo administration of gold sodium thiomalate on rat macrophage function. 681 20

Three potential inhibitors of lysosomal enzyme release, chloroquine, hydroxystilbamidine, and dapsone were tested for their effects on the release of previously incorporated 45Ca and beta (beta)-glucuronidase from fetal rat long bones cultured in a chemically defined medium. At concentrations of 10(-5) to 10(-8)M, all three agents were able to inhibit the stimulation of bone resorption by parathyroid hormone (PTH) or prostaglandin E2 (PGE2). Inhibition was seen at concentrations which did not alter the uptake of (3H)-2-deoxy-glucose or the incorporation of (3H)-thymidine in bone. While the inhibitors blocked the stimulation of beta-glucuronidase release by PTH and PGE2, they could also cause a direct increase in total beta-glucuronidase content and release. Hence the usual strong correlation between the release of beta-glucuronidase and 45Ca was no longer seen in the presence of inhibitors. These data indicate that chloroquine, hydroxystilbamidine, and dapsone are potent inhibitors of bone resorption which may act by blocking the release of lysosomal enzymes in cells stimulated by PTH or PGE2, but may have a different effect on other cell populations.
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PMID:Chloroquine, hydroxystilbamidine, and dapsone inhibit resorption of fetal rat bone in organ culture. 681 1

We have isolated from monkey (Macaca radiata) brain lysosomal fraction by phosphomannan-Sepharose chromatography a protein that binds four different lysosomal enzymes, beta-hexosaminidase, beta-glucuronidase, alpha-L-fucosidase and arylsulfatase. The isolated protein which appeared in an aggregated homogeneous form on gel electrophoresis under non-denaturing conditions at both pH 8.3 and pH 5.0 was found to be heterogeneous on SDS-gel electrophoresis with molecular weights less than 67,000. Binding was partly abolished by periodate treatment or by alkaline phosphatase treatment of the lysosomal enzymes. Binding was completely abolished by pronase digestion of the binding protein. Of the different sugars tested for inhibition of binding, mannose-6-phosphate was most effective followed by mannose and N-acetyl glucosamine while glucose and fucose were ineffective.
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PMID:A binding protein for lysosomal enzymes isolated from brain by phosphomannan-sepharose chromatography. 684 56

The response of the pony to increasing doses of Escherichia coli endotoxin was evaluated using intravenous and intraperitoneal administration models. Marked changes were seen in all parameters measured following endotoxin administration. Leukopenia (neutropenia, lymphopenia) and thrombocytopenia were not dose-dependent. Similarly, elevated plasma fibrinogen and altered glucose concentrations (hyperglycemia and hypoglycemia), pyrexia and increased lactate/pyruvate ratios were apparent at all endotoxin doses but were not dose related. The widely used packed cell volume and capillary refill time, we well as blood lactate and possibly serum beta-glucuronidase, were increased in a dose-related manner.
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PMID:Dose-response of ponies to parenteral Escherichia coli endotoxin. 702 Aug 94

The mannose- and N-acetylglucosamine-specific pathway for the clearance of mammalian glycoproteins has been characterized by using 125I-labelled neoglycoproteins, glycosidase-treated orosomucoid and lysosomal glycosidases (beta-glucuronidase and beta-N-acetylglucosaminidase) as probes. There are two components to this pathway in vivo; one liver-dependent and the other extrahepatic or liver-independent. Cells that mediate clearance by the latter component of the pathway are present in spleen, bone and in elements of the reticuloendothelial system, but not in the kidney. Glycoproteins that possess terminal mannose, glucose or N-acetylglucosamine residues, including various lysosomal enzymes, are rapidly cleared from plasma via this pathway. Glucose-terminated glycoproteins are recognized by two pathways in the intact animal; the hepatic galactose-specific pathway and the mannose/N-acetylglycosamine-specific pathway, which is present in liver and in peripheral tissues. Following removal of the liver by surgical evisceration, glucose-terminated glycoproteins are cleared whereas glycoproteins bearing galactose are not cleared. Uptake of 125I-labelled neoglycoproteins and agalacto-orosomucoid by isolated alveolar macrophages closely mimics clearance in vivo by the mannose/N-acetylglucosamine pathway. Neoglycoproteins terminated by mannose, glucose or N-acetylglucosamine all compete with 125I-labelled agalacto-orosomucoid for uptake by receptor-mediated pinocytosis. The extent of substitution of the neoglycoproteins is a critical determinant of their inhibitory potency. It is proposed that mononuclear phagocytes are in important component of the clearance pathway in vivo. The mannose/N-acetylglucosamine pathway may be important in the regulation of extracellular levels of various glycosylated macromolecules, including lysosomal hydrolases.
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PMID:The role of extra-hepatic tissues in the receptor-mediated plasma clearance of glycoproteins terminated by mannose or N-acetylglucosamine. 723 28

We investigated the mechanisms by which a serum activity, neither complement nor immunoglobulin, mediates killing of pneumococci by polymorphonuclear leukocytes (PMN). Electron microscopy revealed type 25 pneumococci to be within PMN when incubated in normal serum, in serum absorbed twice at 0 degrees C with type 25 pneumococci, or in absorbed plus heat-inactivated serum. Uptake of radiolabeled bacteria, and activation of oxygen consumption and of the hexose monophosphate shunt by PMN with pneumococci, were similar in normal serum, absorbed serum, or the combination of absorbed and heat-activated serum. Reduction of nitroblue tetrazolium (NBT) and of cytochrome c by PMN in the presence of type 25 pneumococci and absorbed serum, with or without heat-inactivated serum were one-third and one-half, respectively, of those in normal serum. Likewise, protein iodination was one-half that in normal serum. Reduction of cytochrome c by cytochalasin B-treated PMN was the same in normal, absorbed, or absorbed plus heat-inactivated serum. Furthermore, release of beta-glucuronidase from PMN after ingestion of pneumococci in 10% normal, absorbed, or absorbed plus heat-inactivated serum was identical. These data indicate that the "third" serum activity is not necessary for attachment of pneumococci to or ingestion by PMN, nor is it necessary for stimulation of the plasma membrane oxidase. Rather, it functions somehow in intracellular killing.
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PMID:Opsonization of pneumococci. II. Metabolic effects of a "third" human serum activity that mediates intracellular killing. 727 78

Ligatin, a receptor that recognizes phosphorylated sugars, was isolated from plasma membranes of mouse macrophages, rat ileum, and rat brain. Several acidic hydrolases including N-acetyl beta-D-glucosaminidase (beta-NAG) were solubilized with this receptor. The solubilized beta-NAG bound to ligatin in vitro as demonstrated by affinity chromatography using the immobilized receptor. beta-N-Acetyl D-glucosaminidase-ligatin complexes were dissociated by low concentrations of mannose 6-phosphate (Man6P) and/or glucose 1-phosphate (Glc 1P). The effectiveness of these two phosphomonosaccharides varied depending on the source of the enzyme: ileal beta-NAG-ligatin complexes showed a four-fold preferential dissociation with Man6P; macrophage complexes showed a 160-fold preferential dissociation with Glc 1P. Brain complexes dissociated with nearly equal preference for Man6P and Glc 1P. Heterologous complexes displayed the specificity characteristic of the source of the enzyme regardless of the source of the ligatin. Treatment of the solubilized hydrolases with endoglucosaminidase H released phosphorous-32 label from these enzymes and prevented binding of beta-NAG to ligatin. However, treatment of the solubilized hydrolases with alkaline phosphatase reduced the binding of beta-NAG to ligatin by no more than 30%. This apparent resistance of beta-NAG to dephosphorylation was consistent with the chromatographic behavior of QAE of 3H-labeled acidic oligosaccharides isolated from the solubilized hydrolases. The oligosaccharides that contain phosphorylated hexose were less acidic than phosphomonoesters and were insensitive to alkaline phosphatase until subjected to acid hydrolysis. These results suggested the presence of a phosphodiester on beta-NAG analogous to the NAC glucosamine 1 P6 mannose present on beta-glucuronidase isolated from mouse lymphoma cells (Tabas I, Kornfield, S: J Biol Chem 255: 6633, 1980).
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PMID:Ligatin binds phosphohexose residues on acidic hydrolases. 729 41

High mannose-type oligosaccharides of acid hydrolases are phosphorylated by the transfer of N-acetyl-glucosamine 1-phosphate to the 6 position of mannose. This is followed by removal of the covering N-acetyl-glucosamine residue to expose a phosphomonoester. We have examined the kinetics of this phosphorylation pathway in the murine macrophage line P388D1. Cells were labeled with [2-3H]mannose for 15-20 min and then chased with unlabeled mannose for various times up to 5 h. The lysosomal enzyme beta-glucuronidase was immunoprecipitated and its oligosaccharide units examined for extent of phosphorylation and uncovering. The first phosphorylated oligosaccharides were detected after 20 min of labeling. Most of the phosphorylation occurred during the first 40 min of the chase period, and a maximum of 30% of the oligosaccharide units were eventually phosphorylated. Oligosaccharides with one and two phosphodiesters were found. The earliest detectable phosphorylated species were devoid of the glucose residues known to be present on the lipid-linked oligosaccharide precursor. Uncovering of the phosphodiesters began shortly after the oligosaccharides were phosphorylated and occurred concomitantly with the removal of outer mannose residues. Taken together, these data demonstrate that phosphorylation of lysosomal enzyme oligosaccharides is a post-translational event. Proteolytic fragmentation of [3H]mannose-labeled beta-glucuronidase and partial digestion of [3H]leucine-labeled beta-glucuronidase with endo-beta-N-acetylglucosaminidase H suggest that there are 3 glycosylation sites per subunit. Each glycosylation site is partially phosphorylated. A portion of the high mannose oligosaccharides at one site are processed to complex-type units.
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PMID:The phosphorylation of beta-glucuronidase oligosaccharides in mouse P388D1 cells. 730 50

Adjuvant induced arthritis in rats was studied by the changes in serum and urinary protein-bound carbohydrate metabolites, changes in serum and tissue lysosomal glycohydrolases and lysosomal fragility. From the second week onwards the urinary excretion of hexosamine and uronic acid is increased. Serum levels of protein bound hexose, hexosamine, sialic acid and fucose are increased significantly in both the acute and chronic phases of the disease. There is no change in the total activity of lysosomal glycohydrolases, viz., beta-glucuronidase, beta-N-acetyl glucosaminidase and cathepsin D in the tissues of liver, kidney and spleen except that of liver enzymes in the chronic phase which are elevated significantly. The free activities of lysosomal glycohydrolases investigated, viz., beta-glucuronidase, beta-N-acetyl glucosaminidase, beta-galactosidase, alpha-mannosidase and cathepsin D are increased in liver and spleen in the acute phase. The free activities of beta-glucuronidase, beta-N-acetyl glucosaminidase and cathepsin D of kidney showed no change whereas those of beta-galactosidase and alpha-mannosidase are increased. In the chronic phase of the disease the free activities of all glycohydrolases are significantly increased in all tissues. Serum glycohydrolases are significantly increased in both acute and chronic phases. Studies on lysosomal preparations showed increased fragility of lysosomes derived from liver and kidney of arthritic rats in both phases of the disease.
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PMID:Glycohydrolases and lysosomal stability in adjuvant induced arthritis. 738 Jun 46


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