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)

Glycosaminoglycans were isolated from purified fractions of glomerular basement membranes and partially characterized by chemical analysis and cellulose acetate electrophoresis. Basement membranes were prepared by detergent treatment of rat glomeruli and subjected to digestion with papain and Pronase. Glycosaminoglycans were isolated from the digests by precipitation with cetyl pyridinium chloride and ethanol. Results of cellulose acetate electrophoresis of the isolated glycosaminoglycan fraction revealed the presence of one major and one minor spot. The major spot was identified as heparan sulfate because it comigrated with the heparan sulfate standard and was sensitive to heparinase and to nitrous acid oxidation but insensitive to chondroitinase ABC and to testicular or leech hyaluronidase. The minor spot was tentatively identified as hyaluronic acid based on its migratory behavior and sensitivity to leech and testicular hyaluronidase. The chemical composition of the isolated glycosaminoglycan was typical of that of heparan sulfate (high carbazole/orcinol ratio, high sulfate content, absence of galactosamine). The data support and confirm the cytochemical data obtained previously [Kanwar, Y. S. & Farquhar, M. G. (1979) Proc. Natl. Acad. Sci. USA 76, 1303-1307] demonstrating that heparan sulfate is the only sulfated glycosaminoglycan detectable in the glomerular basement membrane. The present results suggest that in addition to sulfated glycosaminoglycan some nonsulfated glycosaminoglycan (hyaluronic acid) may also be present in the glomerular basement membrane.
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PMID:Isolation of glycosaminoglycans (heparan sulfate) from glomerular basement membranes. 15 57

Previous studies have used a sensitive histochemical technique to demonstrate acetylcholinesterase and butyrylcholinesterase within the pathological lesions of Alzheimer's disease. In this study, we used this technique to show that acetylcholinesterase localized in either frozen or fixed neocortical tissue sections is removed after treatment with various glycosaminoglycans, heparinases or proteases. Heparan sulphate, heparinase lyase type I and to a lesser degree, heparin and chondroitin sulphate were effective in solubilizing a large part of the cholinesterase activity. At physiological concentrations, the protease papain or trypsin readily removed activity but collagenase or pronase were relatively less effective. Peptide protease inhibitors and divalent metals did not exhibit any clear effect. The specificity of these observations was shown by inhibition of activity with various anticholinesterases including diisofluorophosphate. Our results suggest that acetylcholinesterase is anchored to and may be released from the heparan sulphate glycosaminoglycans shown to be contained in the lesions. We further suggest that the localization of cholinesterases is closely associated with the accumulation of the glycosaminoglycans in amyloid plaques and neurofibrillary tangles.
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PMID:Acetylcholinesterase and its association with heparan sulphate proteoglycans in cortical amyloid deposits of Alzheimer's disease. 146 81

Physiological stimuli induce rapid and unexplained increases in the number of red blood cells within capillaries of skeletal muscle. We hypothesized that such alterations in intracapillary red cell numbers might be due to an undefined interaction between one or more components of blood and the luminal surface of the capillary. This proposition was tested by in situ microperfusion of capillaries with enzymes directed against macromolecules likely to be expressed on the surface of endothelial cells. The instantaneous fractional volume of red blood cells within a capillary (tube hematocrit) was used as an index of a capillary's response to enzyme microperfusion. Five to 8 min of perfusion with enzyme vehicle (0.25% albumin-Ringer solution) produced no significant alteration in capillary tube hematocrit. Perfusion with solutions containing heparinase raised the tube hematocrit at least twofold (P less than 0.05) without a significant change in red cell velocity. Heat-denatured heparinase and other enzymes such as neuraminidase, hyaluronidase, papain, pronase E, and clostripain had no detectable effect on the tube hematocrit (P greater than 0.05). After enzyme treatment, application of adenosine (10(-4) M) or oxygen caused brisk vasomotor responses in arterioles feeding perfused capillary units, but the usual changes in the tube hematocrit were not observed. Thus heparinase treatment results in a sustained elevation in the capillary tube hematocrit and a dissociation of the typical relationship between vasomotor changes and red cell distribution in capillaries. These findings suggest that physiological stimuli which alter the number of red blood cells within capillaries may operate by modifying interactions between plasma and one or more components on the luminal surface of capillaries.
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PMID:Heparinase treatment suggests a role for the endothelial cell glycocalyx in regulation of capillary hematocrit. 231 79

The chemical nature of anionic sites located on both fronts of the endothelial cells (ECs) and in the basement membrane (BM) of mouse brain capillaries was studied using tissue sections embedded in Lowicryl K4M and cationic colloidal gold. Before labelling with cationic probe, the sections were digested with the following enzymes: trypsin, papain, pronase E, proteinase K, collagenase, chondroitinase ABC, hyaluronidase, heparinase, heparitinase, neuraminidase and endoglycosidase H. The results indicate that the negatively charged surface layer on the luminal front differs in chemical nature from that on the abluminal front of the EC. Anionic sites located on the luminal surface of the plasmalemma of the ECs are mainly contributed by sialic acid residues of acidic glycoproteins. On the contrary, the anionic domains on the abluminal front of the EC represent mixed proteoglycan and acid glycopeptides containing hydrophobic amino acids, sialic acid residues, and are rich in heparan sulphate-bearing glycosaminoglycans. The anionic sites of the BM are contributed in a substantial degree by chondroitin and heparan sulphate-rich glycosaminoglycans. The effect of endoglycosidase H suggests that glycopeptides containing oligomannosyl residues linked to N-acetylglucosamine contribute in small degree in maintenance of the negative charge in the BM, but not on the surfaces of the EC. These results show that brain endothelium bears surface anionic domains differing chemically from those described for some fenestrated and continuous endothelia. The distribution of anionic sites indicates that the discrimination against various negatively charged molecules takes place on both fronts of the ECs as well as in the BM of brain micro-blood vessels. The exact role of these domains in the function of the blood-brain barrier remains to be established.
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PMID:Ultracytochemical characterization of anionic sites in the wall of brain capillaries. 274 7

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

The distribution of anionic sites in the basal laminae of the blood capillaries of the murine pancreas was studied in specimens fixed in ruthenium red (RR)-glutaraldehyde mixtures. The sites appeared as discrete, small (6 to 18 nm) particles distributed throughout the three laminae but concentrated primarily in the lamina rara externa, in which--spaced 80-100 nm apart--they formed a planar, partially ordered lattice comparable to that revealed by cationized ferritin in previous studies (M. Simionescu, N. Simionescu, and G. E. Palade, 1982, J. Cell Biol. 95, 425-434). The chemical nature of the anionic sites was explored by incubating fresh tissue specimens in solutions of selected enzymes before fixation in RR-glutaraldehyde mixtures. Pronase P and papain removed completely the anionic sites and left behind an extensively degraded and disorganized basal lamina. Trypsin caused the removal of anionic sites only, did not degrade the rest of the basal lamina, but detached it completely from the endothelium. Chondroitinase ABC reduced slightly the size and the surface density of RR-stainable particles, and detached focally the rest of the basal lamina from the endothelium and pericytes. Crude heparinase caused a nearly complete removal of anionic sites, and pure heparitinase gave comparable but less extensive results. Similar effects were recorded on the basal laminae of smooth muscle fibers and pancreatic acini and ducts. The results indicate that the anionic sites of all basal laminae examined are contributed primarily by heparin sulfate proteoglycans and trace amounts of chondroitin sulfate proteoglycans.
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PMID:Partial chemical characterization of the anionic sites in the basal lamina of fenestrated capillaries. 652 60

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

The alphaherpesvirus pseudorabies virus (PrV) has been shown to attach to cells by interaction between the viral glycoprotein gC and cell membrane proteoglycans carrying heparan sulfate chains (HSPGs). A secondary binding step requires gD and presumably another, hitherto unidentified cellular receptor. By use of a virus overlay protein binding assay (VOPBA), cosedimentation analyses, and affinity chromatography, we identified three species of cell membrane constituents that bind PrV. By treatment with EDTA, peripheral HSPGs of very high apparent molecular mass (>200 kDa) could be extracted from Madin-Darby bovine kidney cells. Binding of PrV to these HSPGs in the VOPBA was sensitive to enzymatic digestion with heparinase or papain. Cosedimentation analyses indicated that binding between PrV and high-molecular-weight HSPG depended on the presence of gC in the virion. In addition, adsorption of radiolabeled PrV virions to cells could be inhibited by the addition of purified high-molecular-weight HSPG. By using urea extraction buffer, a second species of HSPG of approximately 140 kDa could be solubilized. Binding of PrV to this HSPG in the VOPBA was also dependent on the presence of heparan sulfate, since reactivity was abolished after suppression of glycosaminoglycan biosynthesis with NaClO3 and after heparinase treatment. In addition to HSPG, in cellular membrane extracts obtained by treatment with mild detergent, a 85-kDa membrane protein was demonstrated to bind PrV in the VOPBA and affinity chromatography. In summary, we identified three species of cell membrane constituents that bind PrV: a peripheral HSPG of high molecular weight, an integral HSPG of approximately 140 kDa, and an integral membrane protein of 85 kDa. It is tempting to speculate that interaction between PrV and the two species of HSPG mediates primary attachment of PrV and that the 85-kDa protein is involved in a subsequent attachment step.
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PMID:Identification of cell surface molecules that interact with pseudorabies virus. 864 35

This report demonstrates that a single set of identical synthetic multifunctional pores can detect the activity of many different enzymes. Enzymes catalyzing either synthesis or degradation of DNA (exonuclease III or polymerase I), RNA (RNase A), polysaccharides (heparinase I, hyaluronidase, and galactosyltransferase), and proteins (papain, ficin, elastase, subtilisin, and pronase) are selected to exemplify this key characteristic of synthetic multifunctional pore sensors. Because anionic, cationic, and neutral substrates can gain access to the interior of complementarily functionalized pores, such pores can be the basis for very user-friendly screening of a broad range of enzymes.
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PMID:Enzyme screening with synthetic multifunctional pores: focus on biopolymers. 1453 Apr 13