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 effects of several neurohumoral agents and serine proteases on glycoconjugate release from hamster tracheal organ cultures were assessed. The beta-adrenergic agonist isoproterenol inhibited glycoconjugate release, and its effect was abolished by the specific beta-blocking agent propranolol. A cholinergic agonist, pilocarpine, marginally increased glycoconjugate release, and its effect was abolished by the antagonist atropine. Human neutrophil elastase and porcine pancreatic trypsin consistently increased glycoconjugate release by 1.8 to 2.8-fold. When the proteases were inactivated, they were no longer effective in stimulating glycoconjugate release. Histologic and electron microscopic analysis of the protease-treated organ cultures revealed no discernible toxic reaction. In addition, organ cultures prelabeled with chromium 51 did not release an increased amount of radioactivity when treated with the proteases. Biochemical analysis of the glycoconjugates released into the culture medium showed them to be of high molecular weight (90% eluted in the void volume of a Sepharose 6B column) and to be resistant to digestion with hyaluronidase and heparinase, properties consistent with mucous glycoproteins. The mechanism of protease-induced glycoconjugate release is unknown. We speculate that stimulation of airway secretory cells by serine proteases of neutrophilic or other inflammatory cell origin may play a role in the increased airway secretion that is characteristic of acute tracheobronchitis.
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PMID:Serine proteases stimulate mucous glycoprotein release from hamster tracheal ring organ culture. 287 41

Protease inhibition by secretory leukocyte protease inhibitor (SLPI) is accelerated by the sulfated polysaccharides. The nature of the SLPI-polysaccharide interaction, explored with affinity chromatography, indicated that this interaction was sensitive to the charge and type of polysaccharide. Dextran and chondroitin had the lowest affinity for SLPI, followed by dermatan, heparan, and dextran sulfates. While heparin bound SLPI tightly, the highest affinity heparin chains unexpectedly contained a lower level of sulfation than more weakly interacting chains. Heparin oligosaccharides, prepared using heparin lyase I were SLPI-affinity fractionated. Surprisingly, undersulfated heparin oligosaccharides bound SLPI with the highest affinity, suggesting the importance of free hydroxyl groups for high affinity interaction. Isothermal titration calorimetry was used to determine the thermodynamics of SLPI interaction with a low molecular weight heparin, an undersulfated decasaccharide and a tetrasaccharide. The studies showed 12-14 saccharide units, corresponding to molecular weight of approximately 4,800, were required for a 1:1 (SLPI:heparin) binding stoichiometry. Furthermore, an undersulfated decasaccharide was able to bind SLPI tightly (Kd approximately 13 nM), resulting in its activation and the inhibition of neutrophil elastase and pancreatic chymotrypsin. The in vitro assessment of heparin and the decasaccharide and tetrasaccharide using stopped-flow kinetics suggested that heparin was the optimal choice to study SLPI-based in vivo protease inhibition. SLPI and heparin were co-administered by inhalation in therapy against antigen-induced airway hyperresponsiveness in a sheep bronchoprovocation model. Heparin, in combination with SLPI demonstrated in vivo efficacy reducing early and late phase bronchoconstriction. Heparin also increased the therapeutic activity of SLPI against antigen-induced airway hyperresponsiveness.
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PMID:Interaction of secretory leukocyte protease inhibitor with heparin inhibits proteases involved in asthma. 959 92

Circulating endotoxin is elevated in sepsis and plays a role in endothelial dysfunction whereas antithrombin is decreased by virtue of its consumption during complex formation with clotting factors and by proteolytic degradation by granulocyte elastase. Dysfunction of endothelium results in enhanced leukocyte rolling and diapedesis into tissues leading to edema formation and injury. Antithrombin exerts beneficial effects on endothelial function in sepsis. A direct anti-inflammatory action of anti-thrombin in inflammatory cells is exerted via heparan sulfate proteoglycans. In this study, we investigated whether antithrombin affects endotoxin-induced adhesion of neutrophils to human endothelial cells in vitro and whether glycosaminoglycans are involved in its signaling. Adhesion of human neutrophils to monolayers of umbilical vein endothelial cells was tested under static conditions. Endothelial cells were pretreated with endotoxin, interleukin-1, heparinase-I, chondroitinase-ABC or anti-syndecan-4-antibody. Endotoxin and interleukin-1 increased neutrophil adherence to human umbilical vein endothelial cells which was inhibited by antithrombin. Concomitant incubation with pentasaccharide abolished this effect of antithrombin. Treatment of endothelial cells with heparinase or chondroitinase led to higher adhesion and prevented effects of antithrombin. With antibodies to syndecan-4, enhanced adhesion of neutrophils was observed. As studied by Western blotting, endotoxin-induced signaling was diminished by antithrombin and the effect was reversible by chondroitinase or heparinase. From our results, we can conclude that endotoxin-induced adhesion of leukocytes to endothelium can be reversed by ligation of syndecan-4 with antithrombin's heparin-binding site and interferences with stress response signaling events in endothelium.
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PMID:Syndecan-4-dependent signaling in the inhibition of endotoxin-induced endothelial adherence of neutrophils by antithrombin. 1465 50