Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.7 (plasmin)
 9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Digestion of human fibrinogen with human leukocyte elastase in the presence of Ca2+ yields a D-like fragment of Mr 93000. This fragment was purified by gel filtration on Sephacryl S-200 followed by chromatofocusing. The purified fragment was partially characterized and compared with a fragment termed D-cate, which is produced by plasmin digestion of fibrinogen in the presence of Ca2+. The molecular weights of the constituent chains of the D-like fragment and D-cate were similar. The D-like fragment precipitated with antisera directed against D-cate, but not with antisera against fragment E. The name D-elastase for the fragment is suggested. Differences between the D-elastase and D-cate fragments were found in amino-terminal amino acids, in isoelectric point and in the expression of D antigenic determinants. Two major functional differences were demonstrated: fragment D-elastase had a much stronger anticlotting potency than D-cate and the binding of Ca2+ by D-elastase and D-cate differed qualitatively and quantitatively. Since it has been suggested that the calcium-binding and anticlotting properties of D-cate are related to a carboxyl-terminal 13000 stretch of the gamma-chain, the present findings for D-elastase indicate that the differences in these properties between D-cate and D-elastase are due to differences in this area of the molecule.
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PMID:Purification and partial characterization of a D-like fragment from human fibrinogen, produced by human leukocyte elastase. 655 Apr 99

This study has examined the interaction between human leukocyte elastase and alpha 2-plasmin inhibitor, or C1 inactivator, inhibitors of proteases of the complement, kinin, coagulation, and fibrinolytic enzyme systems. Leukocyte elastase, in catalytic concentrations, progressively inactivates the plasmin inhibitory activity of both inhibitors. The C1s binding function of C1 inactivator is also destroyed by leukocyte elastase. The nature of the molecular events underlying the inactivation of these protease inhibitors was examined by acrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. Loss of functional activity was accompanied by limited proteolytic cleavage of both inhibitors with the production of several characteristic derivative peptide chains. Leukocyte elastase cleaved alpha 2-plasmin inhibitor at two separate sites and generated lower molecular weight fragments similar to those produced by bovine beta-trypsin. C1 inactivator was hydrolyzed at three different regions on the molecule whereas beta-trypsin cleaved two regions in common with leukocyte elastase. These findings suggest that inactivation of alpha 2-plasmin inhibitor and C1 inactivator by leukocyte elastase released in the inflammatory reaction may potentiate pathological proteolysis. The limited digestion of these inhibitory proteins by leukocyte elastase may prove useful in studies of their primary structure.
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PMID:Proteolytic cleavage and inactivation of alpha 2-plasmin inhibitor and C1 inactivator by human polymorphonuclear leukocyte elastase. 698 Aug 81

The association rate constants for the interaction of alpha-1-proteinase inhibitor, oxidized alpha-1-proteinase inhibitor, and alpha-1-antichymotrypsin with several mammalian serine proteinases have been determined. The results indicate that leukocyte elastase reacts more rapidly with alpha-1-proteinase inhibitor than any other proteinase tested, while leukocyte cathepsin G shows the strongest association with alpha-1-antichymotrypsin. Oxidation of the critical methionine residue of alpha-1-proteinase inhibitor reduces the association with leukocyte elastase by a factor of more than 2000 and also lowers the association with all of the other enzymes tested with the exception of chymotrypsin. Significantly, oxidation completely abolishes any interaction of alpha-1-proteinase inhibitor with porcine elastase, human plasmin or human thrombin. These data support previous results (Johnson, D., and Travis, J. (1979) J. Biol. Chem. 254, 4022-4026) which indicated that oxidation of human alpha-1-proteinase inhibitor in vivo could reduce the effectiveness of this inhibitor in controlling proteolysis. In the lung, in particular, oxidizing agents of both chemical and biological sources could, indirectly, augment elastolysis in this tissue, resulting in the development of pulmonary emphysema.
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PMID:Kinetics of association of serine proteinases with native and oxidized alpha-1-proteinase inhibitor and alpha-1-antichymotrypsin. 698 30

The human neutrophil peptide-generating protease, which generates a low molecular weight vasoactive peptide from a plasma protein substrate, is directly fibrinolytic and cleaves human fibrinogen in a manner distinct from plasmin. Fibrinogen was reduced from 340,000 Mr to derivatives of 270,000-325,000 Mr during interaction with the protease at enzyme-to-substrate ratios of 0.3 or 1.0 microgram/1.0 mg. The 310,000-325,000 Mr cleavage fragments exhibited prolonged thrombin-induced clotting activity but were able to be coagulated, whereas the 270,000-290,000 Mr fragments were not able to be coagulated. Anticoagulants were not generated at either enzyme dose. As analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis in 4-30% gradient gels and 10% gels stained for protein and carbohydrate, the diminution to 310,000-325,000 Mr and the prolongation of thrombin-induced clotting time resulted from cleavage of the fibrinogen A alpha chain. The further decrease in size to 270,000-290,000 Mr was associated with B beta-chain and gamma-chain cleavage and an inability to form gamma-gamma dimers. The neutral peptide-generating protease, a distinct human neutrophil neutral protease with fibrinolytic and fibrinogenolytic activities comparable to those of plasmin on a weight basis, cleaves fibrinogen in a manner that is distinct from the action of plasmin, leukocyte elastase, and leukocyte granule extracts. It may be that the concerted action of this neutrophil protease to generate a vasoactive peptide and to digest fibrinogen and fibrin facilitates neutrophil movement through vascular and extravascular sites.
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PMID:Cleavage of fibrinogen by the human neutrophil neutral peptide-generating protease. 700 79

Urokinase activation of blood fibrinolysis involves polymorphonuclear leukocytes. To determine if a leukocyte proteinase can modulate plasminogen activation, plasminogen was digested with leukocyte elastase. A major product was a small, approximately 34,000 dalton fragment (mini-plasminogen), without lysine-binding function, but with fibrin-binding activity. After urokinase activation, the resulting mini-plasmin had amidolytic activity for a tripeptide plasmin substrate and fibrinolytic activity. By 125I-fibrin assay, activities of mini-plasmin and plasmin (12 nmole/liter) were 38 and 20 ng fibrin lysed/min, respectively. Lysis times of fibrin clots containing urokinase, and mini-plasminogen or plasminogen (800 nmole/liter), were 282 and 290 sec, respectively. Mini-plasmin and plasmin were inhibited similarly by epsilon-aminocaproic acid and normal plasma, but differed in responses to gel filtration fractions of plasma containing alpha 2-antiplasmin and alpha 2-macroglobulin, the primary and secondary plasmin inhibitors. With purified inhibitors, mini-plasmin required higher concentrations of, or longer preincubation with, alpha 2-antiplasmin, and lower concentrations of, or shorter preincubation with, alpha 2-macroglobulin, to produce inhibition equivalent to that observed with plasmin. Leukocyte elastase digests plasminogen to generate a mini-plasminogen which, when activated by urokinase, has a novel pattern of response to the major plasmin inhibitors in plasma.
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PMID:Mini-plasminogen: a mechanism for leukocyte modulation of plasminogen activation by urokinase. 701 19

The effect of solid-phase fibrin on the inactivation of plasmin, miniplasmin, and neutrophil leukocyte elastase (PMN-elastase) by plasma protease inhibitors (alpha 2-antiplasmin, alpha 1-protease inhibitor, alpha 2-macroglobulin) was studied. In Hanks' balanced salt solution, fibrin reduces the second-order rate constant for the inhibition of PMN-elastase by alpha 1-protease inhibitor from 8,760 x 10(4) to 4 x 10(4) M-1.s-1 and by alpha 2-macroglobulin from 121 x 10(4) to 1.8 x 10(4) M-1.s-1. The rate constant for miniplasmin inactivation by alpha 2-antiplasmin decreases from 99 x 10(4) to 1 x 10(4) M-1.s-1, by alpha 2-macroglobulin from 78 x 10(4) to 1.8 x 10(4) M-1.s-1, and by alpha 1-protease inhibitor from 0.11 x 10(4) M-1.s-1 to 0. Plasmin bound to fibrin is completely protected against alpha 2-macroglobulin and alpha 1-protease inhibitor, whereas the rate constant for the inactivation by its primary plasma inhibitor alpha 2-antiplasmin is reduced from 430 x 10(4) to 1.08 x 10(4) M-1.s-1. The competition of substrate and inhibitor for the enzyme was also studied, using fibrin preincubated with inhibitor. Under our pseudo-first-order experimental conditions, fibrin completely eliminates those interactions, the second-order rate constant of which is 1.1 x 10(5) M-1.s-1 or less in a system without fibrin surface.
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PMID:Regulation of fibrinolytic activity of neutrophil leukocyte elastase, plasmin, and miniplasmin by plasma protease inhibitors. 751 29

The effect of heparin on the inactivation rates of fibrin-bound plasmin, miniplasmin and neutrophil leukocyte elastase (PMN-elastase) by their plasma inhibitors was studied. While plasmin and miniplasmin bound to fibrin are not inactivated by antithrombin, heparin (800 nM) makes these enzymes available for the inhibitor; the second-order rate constant increases from zero to 1.3 x 10(3) M-1 s-1 and 3.3 x 10(3) M-1 s-1, respectively. Heparin slightly increases the rate of fibrin-bound enzyme inactivation by plasmin inhibitor. alpha 1-Protease inhibitor, on the other hand, is unable to inactivate plasmin or miniplasmin bound to fibrin and heparin has no facilitating effect. In the case of PMN-elastase, heparin (300 nM) further increases enzyme protection against alpha 1-protease inhibitor; the rate constant decreases from 41 x 10(3) M-1 s-1 to 23 x 10(3) M-1 s-1. alpha 2-Macroglobulin inhibits fibrin-bound miniplasmin and PMN-elastase with a second-order rate constant of 1.8 x 10(4) M-1 s-1 and heparin (300 nM) increases the rate insignificantly for miniplasmin and by a factor of two for PMN-elastase. It is remarkable that plasmin bound to fibrin is not inhibited by alpha 2-macroglobulin independently of the presence of heparin. On the basis of the reported kinetic data a lifespan of 420 s for plasmin, 66 s for miniplasmin and 4 s for PMN-elastase was calculated, when the enzymes are bound to fibrin in the presence of the four protease inhibitors at physiological plasma concentration. If heparin is present (300 nM) these values decrease to 240 s for plasmin and 42 s for miniplasmin, whereas that of PMN-elastase is unchanged. Thus, the present in vitro kinetic model suggests an antifibrinolytic effect of heparin in a plasma milieu.
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PMID:Heparin modulation of the fibrinolytic activity of plasmin, miniplasmin and neutrophil leukocyte elastase in the presence of plasma protease inhibitors. 753 86

The human intracellular serine proteinase inhibitor, proteinase inhibitor 6 (PI-6), was expressed in the methylotropic yeast Pichia pastoris. The PI-6 cDNA was modified to encode six histidine residues immediately after the initiation codon, and was placed under the control of the P. pastoris alcohol oxidase promoter in the vector pHIL-D2. On the methanol induction, active recombinant PI-6 was produced within the yeast cells, and following cell lysis, was separated from yeast proteins by affinity chromatography using nickel nitrilo-tri-acetic acid (NTA) resin. The interaction of recombinant PI-6 with a range of serine proteinases was studied. Second order association rate constants (ka) were derived for the interaction with trypsin (1.8 x 10(6) M-1 s-1), thrombin (1.2 x 10(5) M-1 s-1), urokinase plasminogen activator (4.0 x 10(4) M-1 s-1), plasmin (1.3 x 10(6) M-1 s-1), and activated protein C (7.5 x 10(3) M-1 s-1). By monitoring complex formation, recombinant PI-6 was also shown to interact with factor Xa. No complex formation was observed with chymotrypsin, human leukocyte elastase, cathepsin G and tissue plasminogen activator, although PI-6 is apparently a substrate for chymotrypsin, leukocyte elastase and cathepsin G.
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PMID:Production and characterization of recombinant human proteinase inhibitor 6 expressed in Pichia pastoris. 754 63

A purified human urinary trypsin inhibitor (UTI) and its related synthetic peptides were examined to determine whether they could inhibit production of experimental and spontaneous lung metastases by murine Lewis lung carcinoma (3LL) cells. Three peptides, peptide I, peptide 2 and peptide 3, representing the amino acid sequences within the UTI molecule, were synthesized. UTI and peptide 2 inhibited human leukocyte elastase (HLE). UTI and peptide 3 specifically inhibited human and murine plasmin activity. Peptide I had essentially no inhibitory activity. In an in vivo spontaneous metastasis model, multiple s.c. injections of UTI or peptide 3 for 7 days immediately after s.c. tumor cell inoculation significantly inhibited the formation of lung metastasis in C57BL/6 mice in a dose-dependent manner. UTI reduced lung tumor colonization more effectively than peptide 3. Peptides 1 and 2, however, did not affect the formation of lung metastasis. Inhibition of lung metastasis was not due to direct anti-tumor effects of UTI and peptide 3. In an in vivo experimental metastasis assay, multiple s.c. injections of UTI for 7 days after i.v. tumor cell inoculation inhibited metastatic lung tumor colonization, while peptide 3 did not affect metastasis. Peptides 1 and 2 did not affect the formation of lung metastasis. When examined with an in vitro assay system using a modified Boyden chamber, UTI and peptide 3 suppressed the invasion of tumor cells through Matrigel. UTI and peptide 3 inhibited neither cell proliferation nor the binding of tumor cells to Matrigel and showed no significant suppression of chemotactic migration of tumor cells to fibronectin. Our results suggest that UTI efficiently regulates the mechanism involved in not only the entry into vascular circulation of tumor cells (intravasation, though, at least in part, inhibition of the proteolytic enzyme plasmin) but also the extravasation step of the metastatic process.
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PMID:Inhibition of metastasis of Lewis lung carcinoma by urinary trypsin inhibitor in experimental and spontaneous metastasis models. 759 Dec 48

Urinary trypsin inhibitor (UTI) has a multipotent inhibitory effect on proteases such as trypsin, chymotrypsin, plasmin, human leukocyte elastase, or hyaluronidase. UTI can bind easily to its receptors on various types of tumor cells (human ovarian cancer HOC-I cells, human choriocarcinoma SMT-cc1 cells, and murine Lewis lung carcinoma 3LL cells). Our results show that the UTI receptors of some tumor cells have a possible role in modulating plasmin activity on the cell surface and prevention of tumor cell invasion and metastasis (H. Kobayashi et al., J. Biol. Chem., 269; 20642-20647, 1994). UTI interacts with tumor cells as a negative modulator of the invasive cells. We investigated whether this effect may be mediated by UTI binding to the cell surface receptors. In addition, the role of peptide sequences from each UTI domain and their interaction with tumor cells were investigated. UTI derivatized with biotin or FITC was taken up by tumor cells in a dose-dependent manner. This cell association was inhibited with a monoclonal antibody D1, which specifically recognizes NH2 terminus (domain I) of UTI. The binding was inhibited by fluid phase UTI, but not HI-8, COOH terminus (domain II) of UTI, suggesting that UTI binds to cells through a site in the UTI domain I. Furthermore, we found that UTI, HI-8 and a number of peptides containing Arg-Gly-Pro-Cys-Arg-Ala-Phe-Ile promoted the inhibition of tumor cell invasion. This site corresponds to the plasmin-inhibiting domain within HI-8. The possibility that UTI binding to tumor cells might be involved in the prevention of tumor cell invasion in vitro was excluded since HI-8, lacking domain I, promotes the inhibition of tumor cell invasion with essentially the same affinity as UTI. All these data allow us to conclude that inhibition of tumor cell invasion is mediated by domain II, which possesses anti-plasmin activity.
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PMID:Inhibition of tumor cell invasion through matrigel by a peptide derived from the domain II region in urinary trypsin inhibition. 772 51


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