Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.37 (neutrophil elastase)
 4,078 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The antibacterial activity of a myeloperoxidase (MPO)-glucose oxidase system was found to be greatly increased by granulocyte elastase, present in azurophil granules of human neutrophils. The MPO-H2O3-mediated killing of both Escherichia coli and Staphylococcus aureus was potentiated by granuocyte elastase at an acid pH, whereas at pH 7.4 only killing of E. coli was potentiated. The potentiating effect of elastase was not dependent on the enzymatic properties of the protein since it was not abolished by heating, which destroys the enzymatic activity. A peptide chloromethyl ketone elastase inhibitor abolished both elastolytic activity and the pctentiating effects on MPO-H2-O2-mediated bacterial killing. The antibacterial activity of chymotrypsin-like cationic protein of human neutrophils was also potentiated by elastase. Other degradative enzymes isolated from human granulocytes, e.g., collagenase and lysozyme, did not potentiate MPO-H2O2-mediated or cationic protein-dependent bacterial killing. The present study indicates that a neutrophil constitutent, elastase, which is not microbicidal by itself, can initiate sublethal changes that render some microorganisms more susceptible to the action of microbicidal agents like MPO and chymotrypsin-like cationic protein.
 ...
PMID:Microbicidal mechanisms of human granulocytes: synergistic effects of granulocyte elastase and myeloperoxidase or chymotrypsin-like cationic protein. 1 11

We have characterized by bioassay and reversed-phase high-performance liquid chromatography analysis (rp-HPLC) the conversion of human big endothelin-1 (bET-1) to endothelin-1 (ET-1) by the cytosolic fraction from human polymorphonuclear leukocytes (PMNs). Either the general serine protease inhibitor 3,4-dichloroisocoumarin (DCI; 50 microM) or the selective elastase inhibitor ONO-5046 (100 microM) blocked the formation of ET-1 from bET-1. Interestingly, human leukocyte elastase formed some of the same products from bET-1 as the PMN cytosol, but generated negligible amounts of ET-1. However, coincubation of the elastase-derived fragments of bET-1 with the PMN cytosol in the presence of ONO-5046 resulted in a 17-fold increase in the formation of ET-1, indicating that an elastase-derived intermediate of bET-1 was subsequently cleaved by a soluble protease(s) to form mature ET-1. We have identified by electrospray-mass spectrometry (ESMS) analysis this intermediate as bET-1(1-22). Analysis of bET-1 digestion by human leukocyte cathepsin G revealed the formation of a biologically active metabolite chromatographically distinct from ET-1, identified as bET-1(1-31) by ESMS. These findings indicate the presence of complex enzyme systems in human PMNs capable of activating bET-1.
 ...
PMID:Characterization of serine protease-derived metabolites of big endothelin in the cytosolic fraction from human polymorphonuclear leukocytes. 128 76

The metabolism of big endothelin 1 (bET) and endothelin 1 (ET-1) by subcellular fractions from human polymorphonuclear leukocytes (PMNs) was investigated by bioassay and reversed-phase high-performance liquid chromatography. More than 80% of endothelin-converting activity was recovered from the cytosolic fraction, which in addition to ET-1 generated other peptides from bET. The processing of bET to all its metabolites including ET-1 was prevented by the serine protease inhibitor 3,4-dichloroisocoumarin (DCI; 50 microM) or the elastase inhibitor ONO-5046 (100 microM) but not by phenylmethylsulfonyl fluoride (PMSF; 143 microM), another serine protease inhibitor. Paradoxically, human leukocyte elastase, despite generating a bET fragmentation pattern similar to that of PMN cytosol, produced very little ET-1. However, subsequent treatment of the elastase-derived metabolites of bET with PMN cytosol in the presence of ONO-5046 dramatically increased the amount of ET-1 formed. The generation of ET-1 following this intervention was inhibited by DCI. The PMN membrane preparation degraded ET-1 to a major metabolite, similar to that produced from ET-1 by elastase, and several minor products, paralleled by a loss of its smooth muscle contracting activity. The degradation of ET-1 by PMN microsomes was prevented by DCI, PMSF, or ONO-5046. Our results suggest that an elastase-initiated serine protease cascade is responsible for the sequential conversion of bET to ET-1 by the PMN cytosol. Elastase also partly accounts for the ET-metabolizing properties of PMN microsomes.
 ...
PMID:The two-step conversion of big endothelin 1 to endothelin 1 and degradation of endothelin 1 by subcellular fractions from human polymorphonuclear leukocytes. 149 79

When human granulocytes were stimulated with the chemotactic peptide FNLPNTL (N-formyl-norleucyl-leucyl-phenylalanyl-norleucyl-tyrosinyl- lysin; in the presence of cytochalasin B), proteolytic enzymes were released which prevented activation of tumor-cell derived pro-uPA by plasmin. Elastase was identified by use of eglin C (elastase inhibitor) and an inhibitory monoclonal antibody to elastase as the functional proteolytic enzyme in these granulocyte supernatants. Purified human granulocyte elastase cleaves pro-uPA at amino acid position lle159-lle160 thus generating an enzymatically inactive two-chain form of uPA, as judged by N-terminal amino acid sequence analysis. An additional minor elastase-mediated cleavage site was detected at position Thr165-Thr166. This form of uPA was indistinguishable by SDS-PAGE from plasmin-generated enzymatically active HMW-uPA. Action of plasmin on the proenzyme form of uPA (pro-uPA) generates an enzymatically active uPA-molecule (high molecular weight form; HMW-uPA) which is cleaved at amino acid position Lys158-lle159 (Mr = 33,000 (B-chain) and 22,000 (A-chain). Thus elastase cannot substitute for plasmin in the proteolytic activation of pro-uPA to enzymatically active HMW-uPA. Enzymatically active HMW-uPA, however, was not affected by elastase. Elastase-containing granulocytes were identified by immunohistochemical staining of elastase in breast cancer tissue. Granulocytes were located close to the tumor cells and also in the tumor stroma surrounding the tumor nests. These tumor cells contain pro-uPA. Evidently, the conversion of tumor cell pro-uPA into enzymatically active HMW-uPA is controlled by elastase released from granulocytes into the tumor tissue.
 ...
PMID:Human tumor cell urokinase-type plasminogen activator (uPA): degradation of the proenzyme form (pro-uPA) by granulocyte elastase prevents subsequent activation by plasmin. 183 19

Leukocyte-derived elastase is released following coronary artery occlusion and reperfusion and may contribute to reperfusion-related myocardial injury. Leukocyte infiltration into the reperfused myocardium may also contribute to ischemic injury following reflow. In the present study, we examined the effects of tissue-plasminogen activator (t-PA, 1 mg/kg over 20 minutes) given intravenously with either saline or a leukocyte elastase inhibitor (ICI 200,880, 5 mg/kg) in dogs with electrically-induced coronary artery thrombosis. ICI 200,880 administration increased elastase inhibitory activity without affecting t-PA and plasminogen activator inhibitor (PAI-1) activities. Time to reflow, magnitude of peak coronary blood flow, and duration of reflow were not different in dogs given t-PA with saline or with the elastase inhibitor. However, administration of the elastase inhibitor decreased the histologically-determined leukocyte infiltration and severity of myocardial injury in dogs subjected to coronary artery thrombosis and subsequent thrombolysis. These early observations suggest that elastase release during reperfusion may be an important mediator of anoxia-reoxygenation-mediated tissue injury.
 ...
PMID:Leukocyte elastase inhibition and t-PA-induced coronary artery thrombolysis in dogs: beneficial effects on myocardial histology. 195 Sep 86

Recently we reported a preliminary characterization of anti-elastase activity which is found in cultured keratinocytes and in epidermis from psoriasis patients, but not in normal human epidermis. Here we present evidence that this inhibitory activity is derived from a cationic protein with a molecular mass of 18 kDa. In psoriatic scales the inhibitor is mainly present as a biologically active 11 kDa fragment. Inhibition of human leukocyte elastase is strong (Ki = 2 x 10(11) M) and fast (kon = 10(7) M-1.s-1). Using chromatofocusing, affinity chromatography and gel-permeation FPLC, the 11 kDa fragment was purified from psoriatic scales. This preparation was reduced and carboxymethylated, blotted onto poly(vinylidene difluoride) membrane and subjected to N-terminal gas-phase sequencing. Within a stretch of 16 amino acids a 40% homology was found with the active site of antileukoproteinase (ALP) a known serine proteinase inhibitor present in mucous secretions. We therefore propose the acronym SKALP (skin-derived antileukoproteinase) as a name for this elastase inhibitor.
 ...
PMID:Skin-derived antileukoproteinase (SKALP), an elastase inhibitor from human keratinocytes. Purification and biochemical properties. 200 28

Three structurally related but functionally different serpins from horse plasma were isolated and characterized. In spite of their identical N-terminal sequences, which show some similarity to that of human alpha 1-proteinase inhibitor, the reactive-centre loops of each of these proteins show extensive variation. Only inhibitor I, with a P1 methionine residue, resembles human alpha 1-PI with regard to (a) similarity of amino acid sequence in the vicinity of the reactive-site peptide bond, (b) broad inhibitory specificity, (c) sensitivity to oxidative inactivation and (d) high rate of reactivity with neutrophil elastase(s). Inhibitor II, with a P1 arginine residue, is an exclusive trypsin inhibitor, and inhibitor III is an oxidation-resistant slow-reacting elastase inhibitor with a P1 alanine residue. Comparison of association rate constants for the inhibition of horse neutrophil elastases by the three inhibitors indicates that only inhibitor I is likely to be physiologically important in the regulation of these enzymes.
 ...
PMID:Comparative properties of three functionally different but structurally related serpin variants from horse plasma. 200 10

The addition of either cathepsin-G or leukocyte elastase to endotoxin-stimulated human peripheral blood monocytes decreased the immunoreactive tumor necrosis factor (TNF) detected in culture supernatants in a concentration-dependent manner. Both enzymes also induced a loss of supernatant cytolytic activity as determined on the WEHI-164 target cell line. Incubation of recombinant human TNF and lymphotoxin (LT) with either cathepsin-G or leukocyte elastase resulted in a loss of cytokine bioactivity. Examination of enzyme-treated recombinant cytokines by gel electrophoresis revealed that cathepsin-G cleaved LT into a 12.6-kDa fragment and leukocyte elastase fragmented LT into a 14.1-kDa product. On Western blots cathepsin-G and leukocyte elastase degraded TNF into 11- and 7.6-kDa fragments, respectively. Incubating leukocyte elastase with plasma elastase inhibitor alpha-1-antitrypsin prevented the loss of recombinant TNF bioactivity and blocked the degradation of this cytokine. This study suggests that two of the most abundant neutrophil proteases, cathepsin-G and leukocyte elastase, may be important regulators of TNF and LT bioactivity.
 ...
PMID:Cathepsin-G and leukocyte elastase inactivate human tumor necrosis factor and lymphotoxin. 203 73

Cigarette smoking is the major risk factor for development of emphysema. Many people are unable to stop smoking despite skilled support. The elastase-antielastase imbalance hypothesis for the pathogenesis of emphysema suggests that treatment with a supplemental elastase inhibitor might prevent development of emphysema in susceptible people. Many elastase inhibitors have been developed. Poorly soluble inhibitors do not prevent emphysema when tested in an animal model of elastase-induced emphysema. Irreversible inhibitors are effective in a dose-response manner. Reversible but tight-binding large molecular weight inhibitors, which clear slowly from the lungs, are effective in vivo. Small molecular weight, reversible inhibitors prevent haemorrhage after human neutrophil elastase instillation into the lungs but may potentiate emphysema. Only 15% of long-term smokers are susceptible to the development of emphysema. Susceptible smokers can be identified by the development of airflow obstruction. An outcome study of efficacy of elastase inhibitor therapy would be prohibitively expensive. However, a study of the process of development of elastase-induced emphysema is feasible. Measurement of alterations in elastase load of the lungs, elastase derived fibrinopeptides, circulating elastin peptides and urinary desmosines could be used for this purpose.
 ...
PMID:The specific treatment of emphysema. 218 48

Comparison of MeO-Suc-Val-Pro-Phe-CO2Me (29) and MeO-Suc-Ala-Ala-Pro-Phe- CO2Me (25) with their corresponding trifluoromethyl ketones 9a and 9b, respectively, in rat and human neutrophil cathepsin G assays showed the alpha-keto esters to be more potent inhibitors. Likewise, Ac-Pro-Ala-Pro-Ala-CO2Me (21) was more potent than its corresponding trifluoromethyl ketone (9c) in both porcine pancreatic elastase and human neutrophil elastase assays. Within a set of Ala-Ala-Pro-Val-CF3 elastase inhibitors, the carbobenzyloxy (Cbz) N-protecting group conferred greater potency as a P5 site recognition unit for elastase than did dansyl, methoxysuccinyl, or tert-butyloxycarbonyl. Initial inhibition of elastase was greater when trifluoromethyl ketone 9f was added from a stock solution of dimethyl sulfoxide than when it had been buffer-equilibrated prior to assay, which suggests that the nonhydrated ketone is the more effective form of the inhibitor. The most potent elastase inhibitor we report is Na-(Ad-SO2)-N epsilon-(MeO-Suc)Lys-Pro-Val-CF3 (16) which has a Ki of 0.58 nM.
 ...
PMID:Synthesis of peptidyl fluoromethyl ketones and peptidyl alpha-keto esters as inhibitors of porcine pancreatic elastase, human neutrophil elastase, and rat and human neutrophil cathepsin G. 229 31


1 2 3 4 5 6 7 8 9 Next >>