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:4.2.2.7 (heparinase)
1,270 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The aim of this study was to determine the role of heparan sulphate (HS)-binding activity of Helicobacter pylori microbes in their adhesion to and ingestion by inflammatory peritoneal macrophages. Two H. pylori strains expressing sialic acid-specific haemagglutinins but differing in the expression of heparan sulphate-binding capacity were chosen for investigation. The attachment to an ingestion by macrophages of the H. pylori bacteria were estimated by ELISA using anti-H. pylori antibodies. The adhesion of both H. pylori strains could be inhibited by pretreatment of the bacteria with heparin (H), HS or fetuin, as well as by preincubation of the macrophages with heparinase or neuraminidase. However, detailed analysis of the data on the inhibition of bacterial adhesion to macrophages led to the conclusion that the attachment of H. pylori 25 bacteria, which expressed a high heparan sulphate binding, was mainly determined by HS-binding structures. In contrast, the adhesion to macrophages of H. pylori bacteria 17874 microbes, which expressed a weak heparan sulphate binding, was more dependent on the exhibition of sialic acid-dependent haemagglutinins. The described variation in H. pylori bacterial surface structures mediating their adhesion to macrophages could suggest a similar variation in bacterial adhesion to stomach mucosa and maybe in the pathogenicity of H. pylori strains.
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PMID:The role of heparan sulphate-binding activity of Helicobacter pylori bacteria in their adhesion to murine macrophages. 754 50

The binding of albumin to the glomerular capillary wall was studied using albumin-gold in perfused kidneys, the interaction of [3H]albumin with isolated glomeruli at 37 degrees C and 4 degrees C and the interaction at [3H]albumin with purified basement membrane. The albumin-gold was found to bind predominantly to the basement membrane and this interaction could be dissociated with high concentrations of albumin. There was binding of albumin to isolated rat glomeruli which exhibited temperature dependence. Glomeruli exhibited a binding site at both 37 degrees C and 4 degrees C with an association constant in the range of 1 to 3 x 10(4) M-1 that bound 7 x 10(13) molecules/glomerulus. At 37 degrees C, however, there was anomalous Scatchard binding behaviour at relatively higher concentrations of albumin (30 to 50 mg/ml) which could be due to either glomerular cell uptake or the appearance of multiple binding sites or both. The binding of albumin to isolated glomeruli and the glomerular albumin levels in isolated kidney perfusion could largely be accounted for by the binding of albumin to the glomerular basement membrane. The albumin binding to glomeruli at 37 degrees C was enhanced by Pronase digestion and heparinase digestion, but remained unchanged following trypsin treatment or neuraminidase treatment. Similarly, albumin was shown to bind to purified basement membrane preparations. This binding was also enhanced (approximately 80 times) by heparinase digestion but remained unchanged after digestion with chondroitinase ABC or hyaluronidase.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Albumin interaction with the glomerular capillary wall in vitro. 778

The distribution of anionic microdomains has been described in cerebral vessels and more recently in capillaries of peripheral nerve. Evidence is accumulating that these sites play a role in the barrier function of vascular endothelia in the PNS and CNS. The chemical nature of anionic sites has been at least partly determined for cerebral vessels but not in peripheral nerve. This study reports our preliminary investigations to determine the nature of endothelial anionic sites in sciatic nerve. The effects of digestion of ultra-thin sections of nerve with a battery of proteolytic and glycolytic enzymes (papain, trypsin, proteinase K, hyaluronidase, heparinase, heparitinase and neuraminidase) on the distribution of anionic sites was determined using the label, cationic colloidal gold. Papain, a proteolytic enzyme of broad specificity, succeeded in removing the majority of cationic colloidal gold-binding sites on the luminal surface of vascular endothelia. In contrast trypsin and proteinase K were less effective, reflecting their narrower specificity. Hyaluronidase, heparinase and heparitinase did not significantly affect cationic colloidal gold-labelling. However, a considerable reduction in cationic colloidal gold-binding occurred following neuraminidase digestion. These results suggest that, as in cerebral vessels, sialic acid-containing glycoproteins are largely responsible for the negatively charged domains on the luminal membrane of endothelial cells in peripheral nerve.
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PMID:Molecular characterization of anionic sites on the luminal front of endoneurial capillaries in sciatic nerve. 817 16

A human endometrial adenocarcinoma cell line (Ishikawa) has been shown to incorporate [3H]glucosamine and to secrete a radiolabeled high molecular weight compound which is excluded from a Sepharose CL-2B column. The excluded material was resistant to hyaluronidase, chondroitinase ABC, and heparinase. These findings rule out the possibility of this material being a proteoglycan. The susceptibility of this material to digestion with pronase, neuraminidase, and alkaline borohydride treatment strongly suggests that the excluded material is an O-glycosidic glycoprotein. The glycoprotein secreted by Ishikawa cells (ICGP) did not react immunologically with antibodies against either lactoferrin or fibronectin, but did react with an antibody made against tracheal mucin. Conversely, immunoblot analysis revealed that an antibody made against ICGP did not recognize hyaluronic acid, chondroitin, heparin, nasal turbinate mucin, bovine submaxillary gland mucin, lactoferrin, or fibronectin, but did recognize tracheal mucin. Analysis of ICGP amino acid and carbohydrate composition showed that it is rich in serine, threonine, glutamic acid, aspartic acid, and N-acetylneuraminic acid. In this respect, ICGP differs from other mucins, even though it is immunologically similar to respiratory mucin; hence we may consider ICGP to be a mucin-like glycoprotein. Secretion of ICGP can be modulated by Ca(2+)-ionophore and other mucus secretagogues, such as platelet activating factor, carbachol, and monocyte/macrophage mucus secretagogue, all mediators of lung inflammation. Ishikawa cells and anti-ICGP antibody may be used in studies on in vitro regulation of mucin-like glycoprotein synthesis and secretion in the respiratory tract as well as in the endometrium.
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PMID:Characterization of a unique mucin-like glycoprotein secreted by a human endometrial adenocarcinoma cell line (Ishikawa). 818 54

This study examines the role of L-selectin in monocyte adhesion to arterial endothelium, a key pathogenic event of atherosclerosis. Using a nonstatic (rotation) adhesion assay, we observed that monocyte binding to bovine aortic endothelium at 4 degrees C increased four to nine times upon endothelium activation with tumor necrosis factor (TNF)-alpha. mAb-blocking experiments demonstrated that L-selectin mediates a major part (64 +/- 18%) of monocyte attachment. Videomicroscopy experiments performed under flow indicated that monocytes abruptly halted on 8-h TNF-alpha-activated aortic endothelium, approximately 80% of monocyte attachment being mediated by L-selectin. Flow cytometric studies with a L-selectin/IgM heavy chain chimeric protein showed calcium-dependent L-selectin binding to cytokine-activated and, unexpectedly, unactivated aortic cells. Soluble L-selectin binding was completely inhibited by anti-L-selectin mAb or by aortic cell exposure to trypsin. Experiments with cycloheximide, chlorate, or neuraminidase showed that protein synthesis and sulfate groups, but not sialic acid residues, were essential for L-selectin counterreceptor function. Moreover, heparin lyases partially inhibited soluble L-selectin binding to cytokine-activated aortic cells, whereas a stronger inhibition was seen with unstimulated endothelial cells, suggesting that cytokine activation could induce the expression of additional ligand(s) for L-selectin, distinct from heparan sulfate proteoglycans. Under flow, endothelial cell treatment with heparinase inhibited by approximately 80% monocyte attachment to TNF-alpha-activated aortic endothelium, indicating a major role for heparan sulfate proteoglycans in monocyte-endothelial interactions. Thus, L-selectin mediates monocyte attachment to activated aortic endothelium, and heparan sulfate proteoglycans serve as arterial ligands for monocyte L-selectin.
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PMID:Monocyte adhesion to activated aortic endothelium: role of L-selectin and heparan sulfate proteoglycans. 904 58

We studied the binding of cationic liposomes, including didodecyl N-(alpha-(trimethylammonio)acetyl)-D-glutamate chloride (TMAG), to a mouse macrophage-like cell line RAW264.7 to clarify which molecules contribute to the binding of TMAG liposomes to the cell surface. Several types of TMAG liposomes encapsulating [3H]inulin, intra-aqueous markers of liposomes, were prepared and their binding characteristics were compared with those of neutral and negatively charged liposomes. The binding of TMAG liposomes to cells was superior to those of neutral and negatively charged liposomes and increased with increasing TMAG content. Scatchard plots for the binding of TMAG liposomes to the cells were approximately linear, indicating a single class of binding sites. Pretreatment of the cell surface with heparinase, heparitiase, chondroitinase ABC, or neuraminidase did not reduce the binding of TMAG liposomes. These results suggested that neuraminic acid and glycosaminoglycan on the cell surface have little contribution to TMAG liposome binding. Pretreatment of the cells with trypsin reduced the binding of TMAG liposomes in a concentration-dependent manner but did not detach the cells from the culture plates. In addition, alpha-chymotrypsin pretreatment had no effect even up to 5 micrograms/mL. Post-treatment with trypsin enhanced the release of TMAG liposomes from the cell surface in a concentration-dependent manner. These results demonstrated that TMAG liposomes bind to trypsin-sensitive proteins on the cell surface.
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PMID:Contribution of trypsin-sensitive proteins to binding of cationic liposomes to the mouse macrophage-like cell line RAW264.7. 923 17

Observations of blood flow in microvascular networks have shown that the resistance to blood flow is about twice that expected from studies using narrow glass tubes. The goal of the present study was to test the hypothesis that a macromolecular layer (glycocalyx) lining the endothelial surface contributes to blood flow resistance. Changes in flow resistance in microvascular networks of the rat mesentery were observed with microinfusion of enzymes targeted at oligosaccharide side chains in the glycocalyx. Infusion of heparinase resulted in a sustained decrease in estimated flow resistance of 14-21%, hydrodynamically equivalent to a uniform increase of vessel diameter by approximately 1 micron. Infusion of neuraminidase led to accumulation of platelets on the endothelium and doubled flow resistance. Additional experiments in untreated vascular networks in which microvascular blood flow was reduced by partial microocclusion of the feeding arteriole showed a substantial increase of flow resistance at low flow rates (average capillary flow velocities < 100 diameters/s). These observations indicate that the glycocalyx has significant hemodynamic relevance that may increase at low flow rates, possibly because of a shear-dependent variation in glycocalyx thickness.
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PMID:Microvascular blood flow resistance: role of endothelial surface layer. 937 63

Small dense low density lipoprotein (LDL) particles have altered apolipoprotein (apo) B conformation and lowered affinity for the LDL receptor (J. Biol. Chem. 1994. 269: 511-519). Herein, we examine the interaction of small dense LDL with cell LDL receptor-independent binding sites. Compared to normal LDL, at low LDL cell media concentrations (<10 microg/ml), small dense LDL had decreased specific binding to the LDL receptor on normal fibroblasts at 4 degrees C, but a 2-fold increased binding to LDL receptor-independent cell sites. At higher LDL concentration (100 microg/ ml), LDL receptor-independent binding of small dense LDL was 4.5-fold that of normal LDL in normal fibroblasts, but greater (2- to 14- fold) in LDL receptor-negative fibroblasts. In LDL receptor-negative fibroblasts at 37 degrees C, small dense LDL had higher (3-fold) cell association than normal size LDL but no effective LDL degradation. At high LDL concentrations (> or =100 microg/ml), LDL binding to normal or LDL receptor-negative fibroblasts was not affected by several anti-apoB monoclonal antibodies or by cell pretreatment with proteases, chondroitinase, or neuraminidase. In contrast, pretreating normal and receptor-negative fibroblasts with heparinase and heparitinase decreased LDL cell binding by 35% and 50%, respectively. Similarly, preincubation of receptor-negative fibroblasts with sodium chlorate, an inhibitor of proteoglycan sulfation, decreased LDL binding by about 45%. We hypothesize that small dense LDL might be more atherogenic than normal size LDL due to decreased hepatic clearance by the LDL receptor, and enhanced anchoring to LDL receptor-independent binding sites in extrahepatic tissues (e.g., the arterial wall), a process mediated, in part, by cell surface proteoglycans.
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PMID:Small dense low density lipoprotein has increased affinity for LDL receptor-independent cell surface binding sites: a potential mechanism for increased atherogenicity. 964 58

Types and distribution patterns of glycoconjugates in antral ovarian follicles were investigated in the buffalo, using periodic-acid Schiff (PAS), high iron diamine (HID), low ion diamine (LID) and lectin histochemical staining methods. HID and LID staining procedures were preceded in some cases by digestion with testicular hyaluronidase, Streptomyces hyaluronidase, chondroitinase ABC and heparitinase (heparinase III). Lectin staining was performed with the use of 12 horseradish peroxidase (HRP) lectin conjugates. Some lectin staining procedures were preceded by neuraminidase digestion and saponification. Large amounts of isomeric chondroitin sulphates and a minor quantity of heparan sulphate and hyaluronic acid and/or chondroitin were found in follicular fluid. Lectin staining of buffalo follicular fluid revealed glycoconjugates with different glucidic determinants such as beta-N-acetylgalactosamine, beta-galactose-(1-3)-N-acetylgalactosamine, beta-galactose-(1-4)-N-acetylglucosamine, N-acetylglucosamine, alpha-fucose and alpha-glucose/alpha-mannose, and sialic acid residues. Glycosaminoglycans were absent in the zona pellucida of oocytes in small antral follicles. Acidic glycoconjugates in the zona pellucida were caused by sulphated groups and sialic acid residues. Our data show few internal glucidic residues, such as N-acetylglucosamine in the buffalo zona pellucida but many subterminal beta-N-acetylgalactosamine, alpha- and beta-galactose determinants masked by sialic acids. These findings demonstrate that buffalo follicular fluid has a very heterogeneous composition that is similar to that found in small and large bovine follicles. No differences in composition of the follicular fluid were observed in the follicles examined.
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PMID:Glycoconjugates in small antral ovarian follicles of the river buffalo (Bubalus bubalis L.). 971 61

Heparan sulfates (HS) are long, unbranched, negatively charged polysaccharides that are bound to core proteins. HS in the glomerular basement membrane (GBM) is reported to be important for charge-selective permeability. Aberrant GBM HS expression has been observed in several glomerular diseases, such as diabetic nephropathy and membranous glomerulopathy, and a decrease in HS generally is associated with proteinuria. This study, with the use of a controlled in vivo approach, evaluated whether degradation of HS in rat GBM resulted in acute proteinuria. Rats received two intravenous injections of either heparinase III to digest HS or neuraminidase to remove neuraminic acids (positive control). Urine samples were taken at various time points, and at the end of the experiment, kidneys were removed and analyzed. Injection with heparinase III resulted in a complete loss of glomerular HS as demonstrated by immunofluorescence staining using anti-HS antibodies and by electron microscopy using cupromeronic blue in a critical electrolyte concentration mode. In the urine, a strong increase in HS was found within 2 h after the first injection. Staining for agrin, the major HS proteoglycan core protein in the GBM, was unaltered. No urinary albumin or other proteins were detected at any time point, and no changes in glomerular morphology were noticed. Injection of rats with neuraminidase, however, resulted in a major increase of urinary albumin and was associated with an increase in urinary free neuraminic acid. An increased glomerular staining with Peanut agglutinin lectin, indicative of removal of neuraminic acid, was noted. In conclusion, removal of HS from the GBM does not result in acute albuminuria, whereas removal of neuraminic acid does.
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PMID:In vivo degradation of heparan sulfates in the glomerular basement membrane does not result in proteinuria. 1830 8


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