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)

Protease-like activity which split plasminogen-free fibrin was demonstrated in 2 M KSCN extracts of the lung and spleen of conventional rats. The activity was virtually undetectable in tissue extracts from germ-free rats. The extracts from the conventional rat tissues split fibrin and fibrinogen remarkably at neutral pH, but not casein, when examined using fibrin, fibrinogen-agar and casein-agar plates. The fibrinolytic activity was inhibited by STI and DFP, indicating a serine protease nature. The activity was not inhibited by TLCK, t-AMCHA or dansyl-L-arginine-methylpiperidine amide (a selective synthetic thrombin inhibitor, OM189). It was neither activated nor inhibited by cysteine, KCN or iodoacetic acid. The results obtained indicate that the protease-like activity of the lung and spleen extracted with 2 M KSCN from conventional rats has properties which differ from those of trypsin, plasmin, plasminogen-activator, thrombin, and cathepsin A, B and C.
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PMID:Fibrinolytic activity of lung and spleen extracts observed in conventional but not in germ-free rats. 9 68

Solutions of plasminogen-free human fibrinogen alone or (1) treated with sodium p-chloromercuribenzoate in order to inactivate factor XIII, or (2) enriched with factor XIII, cysteine and CaC12, were clotted with plasmin-free human thrombin and incubated under sterile conditions. The clots dissolved gradually within 2 days (fibrin from sodium p-chloromercuribenzoate-treated fibrinogen) to 15 days (fibrin from factor XIII-enriched fibrinogen). This proteolytic process was not affected by soybean trypsin inhibitor but was completely inhibited by hirudin. Gel electrophoresis of the thrombin digests indicated the formation of bands equivalent to bands X, Y, D and E of plasmin digests of fibrinogen. The two latter bands, whose identity was confirmed by immunoelectrophoresis, appeared at a more advanced stage of proteolysis than the corresponding bands of plasmin digests. The number of isopeptide bonds present did not appear to affect the rate of release of acid-soluble peptides. Gel electrophoresis and the rate of release of acid-soluble peptides indicated that fewer bonds are hydrolysed by thrombin at the time of the complete solubilization of the clot than are split by plasmin when fibrinogen becomes unclottable by thrombin.
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PMID:Fibrin digestion by thrombin. Comparison with plasmin-digested fibrinogen. 13 48

Nine samples of human ceruloplasmin [iron(II):oxygen oxidoreductase; EC 1.16.3.1] prepared by different procedures have been examined for heterogeneity; gel electrophoresis showed that seven contained a number of components with molecular weights ranging from 20,000 to 130,000, and two contained largely a single component of molecular weight 130,000. Digestion of a single-component preparation with plasmin produced fragments with molecular weights similar to those found in the multicomponent preparations. Amino-terminal analysis, peptide mapping, and amino acid analysis showed that plasmin digestion generated a fragment of 20,000 molecular weight, which corresponded to a component present in a multicomponent ceruloplasmin preparation. The 20,000 molecular weight fragment appears to correspond to the so-called alpha-subunit or L-chain of human ceruloplasmin. Chemical evidence is thus provided that ceruloplasmin is a single-chain protein and that the so-called subunits are fragments. The 20,000 molecular weight fragment contains a single cysteine; amino acid sequence studies have shown that the sequence in the vicinity of this residue is similar to that around the single cysteine residue in plant plastocyanins and bacterial azurins, which are small, blue, copper-containing proteins.
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PMID:Chemical evidence that proteolytic cleavage causes the heterogeneity present in human ceruloplasmin preparations. 14 97

1. Cathepsin B, a tissue (lysosomal) proteinase, and two humoral proteinases, plasmin and kallikrein, activate the latent collagenase ('procollagenase') which is released by mouse bone explants in culture. Other lysosomal proteinases (carboxypeptidase B, cathepsin C and D) and thrombin did not activate the procollagenase. Dialysis of the culture fluids against 3M-NaSCN at 4 degrees C and, for some culture fluids, prolonged preincubation at 25 degrees C also caused the activation of procollagenase. 2. In all these cases, activation of procollagenase involved at least two successive steps: the activation of an endogenous latent activator present in the culture fluids and the activation of procollagenase itself. 3. An assay method was developed for the endogenous activator. Human serum, bovine serum albumin, casein and cysteine inhibited the endogenous activator at concentrations that did not influence the collagenase activity. N-Ethylmaleimide and 4-hydroxy-mercuribenzoate stimulated the endogenous activator, but iodoacetate had no effect. 4. It is proposed that cathepsin B, kallikrein and plasmin may play a role in the physiological activation of latent collagenase and thus initiate degradation of collagen in vivo. This may occur whatever the molecular nature of procollagenase (zymogen or enzyme-inhibitor complex) might be.
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PMID:Further studies on the activation of procollagenase, the latent precursor of bone collagenase. Effects of lysosomal cathepsin B, plasmin and kallikrein, and spontaneous activation. 19 17

1. A latent neutral proteinase was found in culture media of mouse bone explants. Its accumulation during the cultures is closely parallel to that of procollagenase; both require the presence of heparin in the media. 2. Latent neutral proteinase was activated by several treatments of the media known to activate procollagenase, such as limited proteolysis by trypsin, chymotrypsin, plasmin or kallikrein, dialysis against 3 M-NaSCN at 4 degrees C and prolonged preincubation at 25 degrees C. Its activation often followed that of the procollagenase present in the same media. 3. Activation of neutral proteinase (as does that of procollagenase) by trypsin or plasmin involved two successive steps: the activation of a latent endogenous activator present in the media followed by the activation of neutral proteinase itself by that activator. 4. The proteinase degrades cartilage proteoglycans, denatured collagen (Azocoll) and casein at neutral pH; it is inhibited by EDTA, cysteine or serum. Collagenase is not inhibited by casein or Azocoll and is less resistant to heat or to trypsin than is the proteinase. Partial separation of the two enzymes was achieved by gel filtration of the media but not by fractional (NH4)2SO4 precipitation, by ion exchange or by affinity chromatography on Sepharose-collagen. These fractionations did not activate latent enzymes. 5. Trypsin activation decreases the molecular weight of both latent enzymes (60 000-70 000) by 20 000-30 000, as determined by gel filtration of media after removal of heparin. 6. The latency of both enzymes could be due either to a zymogen or to an enzyme-inhibitor complex. A thermostable inhibitor of both enzymes was found in some media. However, combinations of either enzyme with that inhibitor were not reactivated by trypsin, indicating that this inhibitor is unlikely to be the cause of the latency.
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PMID:The simultaneous release by bone explants in culture and the parallel activation of procollagenase and of a latent neutral proteinase that degrades cartilage proteoglycans and denatured collagen. 20 18

The complete amino acid sequence has been determined for a fragment of human ceruloplasmin [ferroxidase; iron(II):oxygen oxidoreductase, EC 1.16.3.1]. The fragment (designated Cp F5) contains 159 amino acid residues and has a molecular weight of 18,650; it lacks carbohydrate, is rich in histidine, and contains one free cysteine that may be part of a copper-binding site. This fragment is present in most commercial preparations of ceruloplasmin, probably owing to proteolytic degradation, but can also be obtained by limited cleavage of single-chain ceruloplasmin with plasmin. Cp F5 probably is an intact domain attached to the COOH-terminal end of single-chain ceruloplasmin via a labile interdomain peptide bond. A model of the secondary structure predicted by empirical methods suggests that almost one-third of the amino acid residues are distributed in alpha helices, about a third in beta-sheet structure, and the remainder in beta turns and unidentified structures. Computer analysis of the amino acid sequence has not demonstrated a statistically significant relationship between this ceruloplasmin fragment and any other protein, but there is some evidence for an internal duplication.
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PMID:Complete amino acid sequence of a histidine-rich proteolytic fragment of human ceruloplasmin. 28 5

The largest fragment produced by complete cyanogen bromide digestion of the alpha chain of human fibrinogen contains 236 residues and has a calculated molecular weight of 23,949. The complete amino acid sequence of the fragment was determined by the isolation of peptides generated by plasmin, trypsin (including digestion of citraconylated material), staphylococcal protease, and chymotrypsin. In addition, some key subfragmentation was achieved by selective chemical cleavage at tryptophan residues. The fragment has an unusual amino acid composition, more than half of its residues being glycine, serine, threonine, and proline. There are very few nonpolar residues, although 7 of the alpha-chain's 10 tryptophans occur in this fragment. The fragment contains 2 cysteine residues located 30 residues apart which are connected by an intrachain disulfide bond in the native molecule. The tryptophans occur with a definite periodicity that highlights a series of 13-residue homology repeats. The fragment also contains the two principal alpha-chain cross-linking sites.
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PMID:Amino acid sequence studies on the alpha chain of human fibrinogen. Complete sequence of the largest cyanogen bromide fragment. 51 44

Limited proteolytic cleavage of fibronectin and plasma cold-insoluble globulin with cathepsin D produced two major fragments. The smaller, Mr = 72,000 fragment bound to collagen and contained most of the cysteine in the molecule. This region contains intrachain disulfide bonds which maintain a conformation that is necessary for interaction with collagen. Cleavage of the intact protein and the 72,000-dalton fragment with plasmin localized the collagen-binding region in cold-insoluble globulin to a sequence of about 42,000 daltons. This region is located approximately two-thirds of the linear distance from the NH2 terminus of each chain in the dimeric molecule.
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PMID:Isolation of a collagen-binding fragment from fibronectin and cold-insoluble globulin. 76 39

A 38-residue fragment is isolated from carboxymethylated plasminogen. Residues 29-38 have the same sequence as the amino-terminal end of the light chain of plasmin. The sequence 1-28 is therefore the sequence of the carboxyl-terminal end of the heavy chain and contains the specific sequence at which urokinase (EC 3.4.99.26) and other plasminogen-activating serine proteases split. Two of the five carboxymethyl-cysteine residues in the isolated fragment are situated close to the cleavage site and the fragment is not itself a substrate for plasminogen-activators. Residues 1-11 show extensive sequence homology with residues 137-147 and 242-252 in prothrombin, which are located in corresponding regions of the two internally homologous 83-residue structures in the non-thrombin part of the molecule, indicating that such structures may be a common feature of the non-protease part of the larger serine protease zymogens.
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PMID:Amino-acid sequence of activation cleavage site in plasminogen: homology with "pro" part of prothrombin. 105 75

Normal rabbit serum contained two kinds of growth-inhibitory protein, GI-I and GI-II, in latent forms. These latent inhibitors were activated by incubation at 37 degrees C for 12 h, and their activation was lowered by inhibitors for serine, cysteine and metalloproteinases. Both growth inhibitors were highly purified in active forms by successive column chromatographies. GI-I showed a major protein band with an Mr of 18,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, while GI-II showed a major protein band with an Mr of 36,000. GI-I and GI-II half-inhibited the growth of rat tumorigenic cell line (RSV-BRL) at concentrations of 0.5 ng/ml and 10 ng/ml, excess concentrations. Of the 15 cell lines tested, GI-I specifically inhibited the growth of rodent and lagomorph cells, whereas GI-II nonspecifically inhibited the growth of all cell lines tested. Specificities for cell type and malignancy were not observed with either inhibitor. These growth inhibitors were stable to a reducing reagent and proteinase inhibitors, but labile to urea, acid, organic solvents, trypsin, plasmin and heating at 95 degrees C for 5 min. These properties suggested that both growth inhibitors might be distinct from known growth-inhibitory factors.
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PMID:Purification and partial characterization of two types of growth-inhibitory protein latently present in rabbit serum. 137 Oct 74


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