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:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Bovine vitreous body and aorta contain extractable leukocyte elastase inhibitors, which were purified by gel filtration and affinity chromatography on agarose-pancreatic elastase. The purified inhibitor preparation from aorta was resolved by polyacrylamide gel electrophoresis into a main band migrating slightly faster than commercial Trasylol and a more weakly stained band migrating close to chymotrypsinogen. The purified inhibitor preparation from both sources inhibited, in a competitive fashion, purified human leukocyte elastase and was ineffective against bovine trypsin and leukocyte cathepsin G or collagenase. These inhibitors from vitreous body and aorta were distinguishable by several criteria from serum inhibitors.
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PMID:Isolation and partial characterization of neutrophil elastase inhibitors from bovine vitreous and aorta. 337 Oct 70

An inhibitor of neutral proteinases was isolated from the cytosol of bovine leukocytes by anion exchange chromatography on Mono Q and gel filtration on a HPLC TSK column. The gel filtration resulted in two fractions with inhibitory activity which could be identified by sodium dodecyl sulphate-poly-acrylamide gel electrophoresis (SDS-PAGE) under nonreducing conditions as dimer and monomer of the inhibitor. The latter was shown to be homogeneous in SDS-PAGE with an apparent molecular mass of 40 kDa, with calibrated HPLC a molecular mass of 36.5 kDa has been determined. Isoelectric focusing followed by Western blot analysis revealed four bands in the pH range of 5.0 to 5.9. The inhibitor was found in bovine polymorphonuclear neutrophils (PMN), whereas lymphocytes and monocytes lacked this protein. No immunological cross-reactivity between the described cell-derived PMN-inhibitor (PMN-I) and alpha 1-proteinase inhibitor was detectable. The mechanism of inhibition for the serine proteinases chymotrypsin, trypsin, pancreatic elastase and leukocyte elastase was studied. PMN-I could not bind to PMS-chymotrypsin. The reaction of the serine proteinases with the PMN-I was characterized by the determination of the association rate constant kon.
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PMID:Neutral proteinase inhibitors in PMN leukocytes. I. Purification and characterization of a neutral proteinase inhibitor from bovine neutrophils. 342 3

A potent inhibitor of human leukocyte elastase (EC 3.4.21.37) and cathepsin G (EC 3.4.21.20) and of human trypsin (EC 3.4.21.4) has been purified from human parotid secretions. The complete amino acid sequence of this protein has been determined. The sequence suggests that the protein has two domains of about 54 amino acids, each of which contains four disulfide bonds. On the basis of a limited homology to other protease inhibitors, the antielastase and antitrypsin activities are thought to be properties of the C-terminal and N-terminal domains, respectively. The affinity of the inhibitor for leukocyte elastase is very high, suggesting a functional role for the protein in preventing elastase-mediated damage to oral and possibly other mucosal tissues.
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PMID:Isolation, properties, and complete amino acid sequence of human secretory leukocyte protease inhibitor, a potent inhibitor of leukocyte elastase. 346 19

Human lumbar disc tissue when extracted with 4M GuHCl and subjected to dissociative CsCl density gradient ultracentrifugation yielded trypsin inhibitor activity in the low bouyant density fractions (rho less than or equal to 1.38 g/ml). Disc proteoglycans sedimented in the high bouyant density fractions (rho greater than or equal to 1.5 g/ml). Sephadex G75F gel filtration of the low bouyant density protein fractions afforded a major low molecular weight (Kav = 0.5) trypsin inhibitor pool which was further purified by trypsin affinity chromatography. This latter step facilitated separation of the trypsin inhibitors from neutral proteinase activity also present. The trypsin inhibitor fraction so isolated was shown to possess potent inhibitory activity against a range of human serine proteinases including leukocyte elastase and cathepsin G, urokinase, kallikrein, plasmin and thrombin. Significantly this serine proteinase inhibitor preparation effectively prevented degradation of proteoglycans by a neutral proteinase also isolated from the human intervertebral disc.
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PMID:Low molecular weight serine proteinase inhibitors of the human intervertebral disc. 348 24

The major elastase inhibitor of human serum, alpha-1 proteinase inhibitor (A1PI), is susceptible to oxidative inactivation by a variety of agents, including chloramine T. We have examined the effects of chloramine T on the catalytic activity of porcine pancreatic (PPE) and human leukocyte elastase (HLE) and on the elastase inhibitory capacity of hamster, rat, and human serum as well as pure human A1PI. Both PPE and HLE, but not trypsin, were inhibited in a concentration-dependent manner by concentrations of chloramine T greater than 0.1 mM. The abilities of rat and human serum and pure human A1PI to inhibit both PPE and HLE were inhibited in a concentration-dependent manner by chloramine T. In contrast only the ability of hamster serum to inhibit HLE was altered by exposure to chloramine T: inhibition of PPE was not effected. Gel exclusion chromatography disclosed the existence of two major peaks of elastase inhibitory activity in hamster plasma: one, with an approximate molecular weight of 55 K, eluting in the region of A1PI that was sensitive to chloramine T inactivation and one with a molecular weight of approximately 180 K which was chloramine T insensitive. The parenteral administration of chloramine T to hamsters resulted in a modest and transient diminution of the serum HLE inhibitory activity and an equally modest and transient elevation of PPE inhibitory activity.
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PMID:The alteration of hamster serum elastase inhibitory capacities by chloramine T, in vitro and in vivo. 348 48

An inhibitor of serine proteinases from human articular cartilage was purified to homogeneity by sequential ultrafiltration and ion exchange chromatography on CM-Sephadex C-50. The apparent molecular weight of the cationic glycoprotein (pI greater than 10) was determined to be 16.5 X 10(3) by SDS gel electrophoresis. The inhibitor blocked the activity of leukocyte elastase, cathepsin G and trypsin but not leukocyte collagenase. In kinetic studies for the interactions with leukocyte elastase a firm enzyme-inhibitor binding was obtained. Amino acid analyses did not reveal homologies with other serine proteinase inhibitors already purified from human tissues.
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PMID:Purification and characterization of a serine proteinase inhibitor from human articular cartilage. 349 75

Human leukocyte elastase (HLE), a serine protease involved in inflammation and tissue degradation, can be irreversibly inactivated in a time- and concentration-dependent manner by ynenol lactones. Ynenol lactones that are alpha-unsubstituted do not inactivate but are alternate substrate inhibitors that are hydrolyzed by the enzyme. Ynenol lactones that are both substituted alpha to to the lactone carbonyl and unsubstituted at the acetylene terminus are rapid inactivators of HLE and inactivate pancreatic elastase and trypsin more slowly. 3-Benzyl-5(E)-(prop-2-ynylidene)tetrahydro-2-furanone inactivates HLE with biphasic kinetics and an apparent second-order rate of up to 22,000 M-1 s-1 (pH 7.8, 25 degrees C). The rate of inactivation is pH-dependent and is slowed by a competitive inhibitor. The partition ratio is 1.6 +/- 0.1. Rapid removal of ynenol lactone during the course of inactivation yields a mixture of acyl and inactivated enzyme species, which then shows a partial recovery of activity that is time- and pH-dependent. Inactivation is not reversible with hydroxylamine. The enzyme is not inactivated if the untethered allenone is added exogenously. All of these results are consistent with a mechanism involving enzyme acylation at serine-195 by the ynenol lactone, isomerization of the acyl enzyme to give a tethered allenone, and capture of a nucleophile (probably histidine-57) to inactivate the enzyme. Substitution at the acetylene terminus of ynenol lactones severely reduces their ability to inactivate HLE, because allenone formation is slowed and/or nucleophile capture is hindered. Chemical competence of each of these steps has been demonstrated [Spencer, R.W., Tam, T.F., Thomas, E.M., Robinson, V.J.,& Krantz, A. (1986) J. Am. Chem. Soc. 108, 5589-5597].
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PMID:Kinetics and mechanism of human leukocyte elastase inactivation by ynenol lactones. 354 14

Orthorhombic crystals diffracting beyond 1.7 A resolution, have been grown from the stoichiometric complex formed between human leukocyte elastase (HLE) and the third domain of turkey ovomucoid inhibitor (OMTKY3). The crystal and molecular structure has been determined with the multiple isomorphous replacement technique. The complex has been modeled using the known structure of OMTKY3 and partial sequence information for HLE, and has been refined. The current crystallographic R-value is 0.21 for reflections from 25 to 1.8 A resolution. HLE shows the characteristic polypeptide fold of trypsin-like serine proteinases and consists of 218 amino acid residues. However, several loop segments, mainly arranged around the substrate binding site, have unique conformations. The largest deviations from the other vertebrate proteinases of known spatial structure are around Cys168. The specificity pocket is constricted by Val190, Val216 and Asp226 to preferentially accommodate medium sized hydrophobic amino acids at P1. Seven residues of the OMTKY3-binding segment are in specific contact with HLE. This interaction and geometry around the reactive site are similar as observed in other complexes. It is the first serine proteinase glycoprotein analysed, having two sugar chains attached to Asn159 and to residue 109.
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PMID:X-ray crystal structure of the complex of human leukocyte elastase (PMN elastase) and the third domain of the turkey ovomucoid inhibitor. 364 Jul 9

A series of carboxy-alkylamidated and N-acetylated amino acids and peptides were synthesized and examined for their ability to inhibit human leukocyte elastase. The Boc-amino acid alkylamides were found to be potent specific and competitive inhibitors of this enzyme. They were found not to or only poorly inhibit several other serine proteinases such as bovine trypsin, alpha-chymotrypsin, porcine pancreatic elastase and human leukocyte cathepsin G at concentrations less than 10(-4) M. Specificity and maximum inhibition of human leukocyte elastase were achieved when the N-terminus of the amino acid was protected by a t-butyloxy-carbonyl (Boc) group, the oligopeptide fragment consisted of valine residues and when the alkyl chain was between 10 and 12 carbon atoms in length and attached to the C-terminus of the peptide fragment. Highest inhibition was obtained with the compound Boc-[Val]3-NH[CH2]11--CH3 (Ki = 0.21 microM). These specific inhibitors were also found to be non-toxic after oral administration to mice and rats (LD50 greater than 3.0 g/kg body weight).
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PMID:Synthetic inhibitors of human leukocyte elastase, Part 3. Peptides with alkyl groups at the N- or C-terminus. Non-toxic competitive inhibitors of human leukocyte elastase. 364 43

Plasma levels of the HNE-derived fibrinopeptide A alpha 1-21 reflect in vivo enzyme activity. To provide a possible explanation for the presence of circulating A alpha 1-21 in individuals with normal plasma antiproteinase concentrations we investigated whether PMN-associated HNE is more resistant to inhibition than the free enzyme. PMN were stimulated to migrate across 125I-fibrinogen-coated nitrocellulose filters in response to 10(-7) M FMLP, and the extent of fibrinogenolysis was determined by measuring release of A alpha 1-21 and 125I-labeled fibrinogen degradation products. The fibrinogenolytic activity of migrating PMN was then compared with that of free HNE present in PMN lysates or secreted by PMN stimulated with FMLP. Whereas the fibrinogenolytic activity of soluble HNE was completely inhibited by low concentrations (1%) of plasma or serum and macromolecular antiproteinase (alpha 1 proteinase-inhibitor and soybean trypsin-inhibitor), even in the presence of undiluted plasma or serum the activity of the migrating PMN was incompletely blocked (81-85%). Further, concentrations of alpha 1 proteinase-inhibitor and soybean trypsin-inhibitor that totally inhibited free HNE activity also incompletely blocked (88-89%) the fibrinogenolytic activity of migrating PMN, indicating that FMLP-stimulated PMN demonstrate significant fibrinogenolytic activity in the presence of antiproteinases as small as 20,000 mol wt. A specific low molecular weight HNE inhibitor (MeO-Suc-Ala2-Pro-ValCH2Cl), however, totally blocked PMN-mediated fibrinogenolysis without affecting intracellular HNE activity, HNE secretion from PMN, or PMN migration in response to FMLP. These findings support the hypothesis that PMN migrating on a fibrinogen-coated surface form zones of close contact with fibrinogen, thus preventing access of plasma antiproteinases to HNE released at the cell-substrate interface. The occurrence of this phenomenon in vivo would explain the presence of circulating A alpha 1-21 in individuals with normal antiproteinase concentrations.
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PMID:Elastase-mediated fibrinogenolysis by chemoattractant-stimulated neutrophils occurs in the presence of physiologic concentrations of antiproteinases. 368 Nov 93


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