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 polycation hexadimethrine (HDM) binds to anionic sites in the glomerular basement membrane (GBM) and causes heavy proteinuria when infused in vivo. An in vitro assay of 3H-HDM binding to isolated dog GBM was developed, to permit further analysis of the GBM components binding HDM. 3H-HDM binding to isolated GBM was saturable, reversible in dose-dependent fashion by competing polycations, and inhibited by increasing salt concentration and low pH. The pH dependence of binding suggested that most of the HDM binds to carboxyl groups rather than to the sulfate groups of proteoglycans. Removal of heparan sulfate by heparinase or purified heparatinase had no detectable effect on HDM binding. Treatment of GBM with neuraminidase, hyaluronidase, or chondroitinase reduced binding of HDM by a maximum of 20 to 38%. However, substitution of carboxyl anions with nonionizable glycine methyl ester residues resulted in complete elimination of HDM binding. Parallel results were obtained in studies of glomerular localization of cationized ferritin (CatF), pI 8.5. After carboxyl substitution, GBM did not bind CatF; heparinase-treated GBM bound CatF in a distribution not demonstrably different from normal. Cellulose acetate electrophoresis of glycosaminoglycan fractions prepared from treated GBM confirmed that carboxyl modification did not alter the content or charge of the heparan sulfate of GBM, but heparinase treatment removed at least 90% of heparan sulfate. The results indicate that carboxyl groups are quantitatively more important than heparan sulfate for binding of HDM in vitro. Since HDM causes proteinuria in vivo, carboxyl groups may be important for maintenance of normal permselectivity.
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PMID:Polycation binding to glomerular basement membrane. Effect of biochemical modification. 380 16

The luminal surfaces of the endothelium lining the two surfaces of the aortic arterial (AAR) and ventricular (AVT), and mitral ventricular (MVT) and atrial (MAT), valve cusps were studied with cationic ferritin (CF) and ferritin (Fer)-conjugated lectins (WGA, RCA, SBA). The arterial (AAR) and ventricular (MVT) surfaces of the aortic and mitral cusps, which are exposed to more turbulent fluid mechanical forces and lower wall shear stresses, had the greatest density of CF labeling. The endothelia of the four surfaces displayed a gradient of decreasing density from the nuclear region to the periphery. Neuraminidase, chondroitinase ABC and AC, heparinase, heparitinase, hyaluronidase (testicular), and pronase E digestions suggested that a significant number of the anionic sites labeled by CF are associated with sialoglycoproteins and glycosaminoglycans such as chondroitin 4/6 sulfates, dermatan sulfates, and heparan sulfates. The localization of WGA receptors on the endothelium of AAR and MVT demonstrated a greater density of sialyl moieties than on the AVT and MAT. There was no binding of Fer-RCA with specificity for D-galactopyranosides or Fer-SBA with affinity for N-acetylglucosamine and D-galactose to the endothelium unless it was first treated with neuraminidase. Hence, sialic acids are shown to be among the more superficial components of this glycocalyx and to be largely responsible for the greater densities over the endothelium of AAR and MVT.
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PMID:Anionic surface properties of aortic and mitral valve endothelium from New Zealand white rabbits. 384 Jun 42

Chicken gizzard extract contains a macromolecular glycoprotein that promotes neurite outgrowth of dissociated neurons from the ciliary ganglia of chick embryos. Using conventional purification procedures, the factor responsible for the neurite outgrowth (neurite outgrowth factor (NOF)) was purified about 2000-fold to an apparent single protein band (as judged by agarose-polyacrylamide gel electrophoresis). Twenty fmol/cm2 of the purified NOF bound to the culture well was sufficient to exert maximal neuritic response of cultured ciliary ganglia neurons from 8-day-old chick embryos. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis revealed that NOF migrated as a single polypeptide of 700 and 210 kDa under nonreducing and reducing conditions, respectively. NOF stained with periodic acid-Schiff reagent and had a sedimentation coefficient of 12 s, a Stokes radius of 114 A, and an isoelectric point of about 5.1. Gizzard NOF was trypsin-sensitive, but resistant to treatment with heparinase, beta-galactosidase, and neuraminidase. Antibody prepared against the purified NOF blocked NOF activity in a dose-dependent manner. The antibody did not inhibit the biological activity of mouse laminin, although it cross-reacted weakly with laminin. Immunohistochemical analysis showed that the antibody against NOF strongly stained the extracellular matrix of cells in thin sections of gizzard, skeletal muscle, heart, liver, and ciliary ganglion, and also the membrane and the cytoplasm of cultured gizzard muscle cells. The present data suggest that gizzard NOF is a novel extracellular matrix glycoprotein which has a role in neurite outgrowth promotion from peripheral neurons in vivo. Although unlikely, the possibility that the NOF is a chick laminin could not be excluded.
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PMID:Purification and characterization of a neurite outgrowth factor from chicken gizzard smooth muscle. 390 28

In order to localize and characterize proteoglycans in human lung alveoli, we have used the cationic dye Cuprolinic Blue according to the critical electrolyte concentration method. After staining, five types of Cuprolinic Blue-positive filaments become apparent: two types in the basement membranes of type I and type II epithelial cells respectively and lying in one or two layers; one type, more scattered, localized in the basement membrane of the endothelial cells and another kind associated with collagen fibrils and separated from each other according to the main banding period (+/- 60 nm) of these fibrils. Finally, there was a type of filament which was only locally present at a variety of places. The basement membrane filaments were sensitive to heparinase, heparitinase, pronase (without prefixation) and nitrous acid treatment, but not to Streptomyces hyaluronidase, neuraminidase, chondroitinase ABC, chondroitinase AC, pronase (after prefixation) and 2.0 M MgCl2 treatment. The basement membrane filaments, therefore, represent heparan sulphate-containing proteoglycans. On the other hand, the collagen fibril associated filaments were sensitive to treatment with heparinase, chondroitinase ABC and pronase (without prefixation), but insensitive to Streptomyces hyaluronidase, neuraminidase, nitrous acid, heparitinase, chondroitinase AC, pronase (after prefixation) and 2.0 M MgCl2 (after prefixation) treatment. These filaments thus represent iduronic acid-rich dermatan sulphate-containing proteoglycans. Several physiological functions for these proteoglycans are discussed.
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PMID:Ultrastructural localization and characterization of proteoglycans in human lung alveoli. 397 3

Different cell types within developing chick skeletal muscle were assayed for their ability to release factors into culture media which could affect the survival and neuritic development of labelled motoneurones and lateral motor column explants. Enriched cultures of myotubes, myoblasts, fibroblasts and mesenchyme were prepared by selective preplating and trypsinisation techniques. Degrees of enrichment were assessed immunofluorescently and morphologically; fibroblasts were the main contaminating cell type. Medium conditioned over each cell type was then tested in dose-response assay against both explants and dissociated motoneurones. In both cases the myotube conditioned medium (MCM) promoted the greatest levels of both survival and neuritic outgrowth, and had the greatest relative potency of all of the cell types. When MCM was preincubated over polycationic substrata, it lost the ability to promote neuritic growth; this could be restored if fresh conditioned medium (CM) was added to the cultures. Thus it was demonstrated that within the MCM there are physically separable agents responsible for neurone survival and neurite expression. The neurite-promoting factor (NPF) within the MCM was stable to collagenase, deoxyribonuclease, neuraminidase and chondroitinase ABC, but was destroyed by trypsin and heparinase. These results imply that a heparan sulfate proteoglycan is essential for the activity of the factor.
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PMID:Motoneurone survival and neuritic outgrowth promoted by different cell types in embryonic muscle. 402 82

Glomerular development was studied in the newborn rat kidney by electron microscopy and cytochemistry. Glomerular structure at different developmental stages was related to the permeability properties of its components and to the differentiation of anionic sites in the glomerular basement membrane (GBM) and on endothelial and epithelia cell surfaces. Cationic probes (cationized ferritin, ruthenium red, colloidal iron) were used to determine the time of appearance and distribution of anionic sites, and digestion with specific enzymes (neuraminidase, heparinase, chondroitinases, hyaluronidases) was used to determine their nature. Native (anionic) ferritin was used to investigate glomerular permeability. The main findings were: (a) The first endothelial fenestrae (which appear before the GBM is fully assembled) possess transient, negatively charged diaphragms that bind cationized ferritin and are impermeable to native ferritin. (b). Two types of glycosaminoglycan particles can be identified by staining with ruthenium red. Large (30-nm) granules are seen only in the cleft of the S-shaped body at the time of mesenchymal migration into the renal vesicle. They consist of hyaluronic acid and possibly also chondroitin sulfate. Smaller (10-15-nm) particles are seen in the earliest endothelial and epithelial basement membranes (S-shaped body stage), become concentrated in the laminae rarae after fusion of these two membranes to form the GBM, and contain heparan sulfate. They are assumed to be precursors of the heparan sulfate-rich granules present in the mature GBM. (c) Distinctive sialic acid-rich, and sialic acid-poor plasmalemmal domains have been delineated on both the epithelial and endothelial cell surfaces. (d) The appearance of sialoglycoproteins on the epithelial cell surface concides with the development of foot processes and filtration slits. (e) Initially the GBM is loosely organized and quite permeable to native ferritin ;it becomes increasinly impermeable to ferritin as the lamina densa becomes more compact. (f) The number of endothelial fenestrae and open epithelial slits increases as the GBM matures and becomes organized into an effective barrier to the passage of native ferritin.
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PMID:Assembly of the glomerular filtration surface. Differentiation of anionic sites in glomerular capillaries of newborn rat kidney. 615 76

The location and chemical composition of anionic sites in Bruch's membrane (BM) were examined using cationic probe molecules demonstrable in electron microscopic preparations and tissue digestion with specific degradative enzymes. Ruthenium red and native lysozyme revealed densities distributed at regular intervals in two major components of BM: the basal laminae of the retinal pigment epithelium (RPE) and choriocapillary endothelium (EN). Staining was not observed with succinylated lysozyme (anionic). Colloidal iron also failed to stain BM components. Following crude heparinase treatment at 43 degrees C (specific for heparan sulfate) anionic sites in the RPE basal lamina were not demonstrable with either ruthenium red or native lysozyme. Sites in the EN basal lamina were not affected. Chondroitinase treatment removed almost all of the ruthenium red-positive material in the EN basal lamina; lysozyme binding here was markedly reduced. No changes were observed in the RPE basal lamina after chondroitinase digestion. There was no morphological evidence for site removal by either neuraminidase or leech hyaluronidase, although a detachment of the RPE from BM often occurred after incubation of eye tissue in the latter. Pronase E removed all stainable material. These findings indicate that anionic sites in BM consist to a large extent of chondroitin sulfates and heparan sulfate.
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PMID:Location and chemical composition of anionic sites in Bruch's membrane of the rat. 617 64

Rat sympathetic neurons, plated onto extracellular matrix produced by cultured bovine corneal endothelial cells, rapidly extended neurites in the absence of nerve growth factor (NGF). The response was unaffected by antiserum to NGF. Rapid outgrowth also occurred when sympathetic neurons were plated onto polylysine-coated surfaces that had been exposed to serum-free medium conditioned by corneal endothelial cells (CMSF). A response was seen even when the neurons were cultured without serum. When plated onto a polylysine-coated dish treated with CMSF over half its surface, only the neurons on the treated half extended neurites. The active factor in CMSF was destroyed by trypsin, acid (pH 1.6), base (pH 12.7), or heating to 80 degrees C; it was stable to heating to 60 degrees C, collagenase, deoxyribonuclease, and neuraminidase. The factor elutes just after the void volume of a Sepharose 6B column. In associative cesium chloride gradients, it sediments as a peak centered at a density of 1.36-1.37, corresponding to a peak of material that can be biosynthetically labeled with [35S]sulfate or [3H]leucine. Material from this fraction was inactivated by heparinase, but not chondroitinase ABC, implying that a heparin sulfate proteoglycan is essential for the factor's activity. Inactivation by contaminants in the heparinase preparation was ruled out. Further purification indicated that the active factor may exist as an aggregate containing a heparin sulfate proteoglycan and other molecules. CMSF also promoted neurite outgrowth by other types of neurons. Furthermore, a variety of cell types were shown to produce factors similar to that in CMSF.
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PMID:Characterization of a factor that promotes neurite outgrowth: evidence linking activity to a heparan sulfate proteoglycan. 621 11

To investigate the chemical nature of the cationic ferritin (CF)-binding sites of the differentiated microdomains of the capillary endothelium, the vasculature of the mouse pancreas and intestinal mucosa was perfused in situ with neuraminidase, hyaluronidase, chondroitinase ABC, heparinase, and three proteases: trypsin, papain, and pronase. Proteases of broad specificity removed all anionic sites, suggesting that the latter are contributed by acid glycoproteins or proteoglycans. Neuraminidase, hyaluronidase, and chondroitinase ABC reduced the density of CF-binding sites on the plasmalemma proper, but had no effect on either coated pits or fenestral diaphragms. Heparinase removed CF-binding sites from fenestral diaphragms and had no effect on coated pits. Taken together, these results indicate that the anionic sites of the fenestral diaphragms are contributed primarily by heparan sulfate and/or heparin, whereas those of the plasmalemma proper are of mixed chemical nature. The membranes and diaphragms of plasmalemmal vesicles and transendothelial channels do not bind CF in control specimens; this condition is not affected by the enzymic treatments mentioned above.
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PMID:Differentiated microdomains on the luminal surface of the capillary endothelium. II. Partial characterization of their anionic sites. 645 53

Using the sialic acid-specific lectin, limulin (LPA; from Limulus polyphemus hemolymph), the distribution and nature of sialoglycoconjugates on the surface of rat pancreatic cells has been investigated. Binding of rhodaminated LPA (Rh-LPA) or horseradish peroxidase-conjugated LPA (HRP-LPA) to fixed-frozen sections of adult rat pancreas resulted in intense linear staining of the apical surface of acinar cells with fainter staining on the basal but not the lateral cell surfaces. LPA binding was specific in that it could be abolished by 1) pretreatment of tissue sections with neuraminidase or periodic acid; 2) competition with sialic acid; and 3) incubation in Ca2+ -free buffers. Pretreatment of sections with proteases abolished LPA binding to the apical surfaces of acinar cells and also enhanced LPA binding to the lateral cell surface. Lipid extraction of sections following protease treatment markedly reduced LPA binding to the acinar cell periphery. These results suggest that LPA binding sites on the acinar cell apical surface may be primarily sialoglycoproteins, while those on the basolateral surfaces may consist in part of gangliosides. Electron microscopy of collagenase-dispersed acini exposed to HRP-LPA confirmed binding of LPA to the basal plasmalemma and, in addition, revealed staining of basal lamina when present. LPA binding to the acinar cell surface was not affected by digestion of tissue sections with hyaluronidase, heparinase, collagenase, or 6 M guanidine-HCl. Control experiments indicated that rat pancreatic secretory proteins contain undetectable amounts of sialoglycoproteins and thus that the apical localization of LPA is not due to adherent secretory proteins. Islets of Langerhans were always uniformly and heavily stained with LPA conjugates; this staining was protease insensitive. Appearance of LPA binding sites was examined on embryonic pancreatic epithelia. At day 15 of gestation, Rh-LPA stained the entire periphery of the epithelial cells, including the lateral cell surface, although more intense staining was already noted on the apical surface. This pattern persisted through day 17 of gestation, but by day 19 an adult staining pattern was observed with loss of staining of the lateral cell surfaces.
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PMID:Distribution of sialoglycoconjugates on acinar cells of the mammalian pancreas. 675 68


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