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)

The mechanism of water-induced pruritus in patients with polycythemia vera is unknown. Evidence has been presented previously that bathing or showering may trigger mast cell degranulation and that release of a mediator by mast cells may be responsible for the pruritus. Tryptase is a specific marker of human mast cell secretory granules and its presence in body fluids indicates mast cell degranulation. In this study, serum tryptase levels were measured both before and one hour after showering in 11 patients suffering from polycythemia vera and water-induced pruritus. Tryptase was not found in the serum of any of the subjects one hour after showering, when levels would be expected to be near peak had significant mast cell degranulation occurred. These results argue against mass cell degranulation with systemic release of a mast cell product as the mechanism for water-induced pruritus in patients with polycythemia vera.
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PMID:Polycythemia vera and water-induced pruritus: evidence against mast cell involvement. 816 24

In order to obtain selective suicide substrates of trypsin-like proteases including plasminogen activators, plasmin, and thrombin, a series of cyclopeptides cyclo[Arg or Lys-aB(CH2X)-Gly4], in which a substituted o- or m-aminobenzoyl group constitutes a latent electrophile, have been prepared. Treatment of the corresponding phenyl ethers cyclo[P1-aB(CH2OC6H5)-Gly4] with HBr/HOAc or R1R2S/TFA gives the bromides (X = Br) or the sulfonium salts (X = +SR1R2 with R1 = R2 = Me or R1 = Me and R2 = C6H5), respectively. These water-soluble cyclopeptides behave as time-dependent inhibitors of bovine trypsin and human urokinase (u-PA) but have no effect on tissue plasminogen activator (t-PA) and no or poor effect on plasmin and thrombin. The compounds containing a m-aminobenzoic acid residue are more efficient inactivators than their anthranilic analogues. The kinetic criteria expected for a suicide inhibition are met. A mechanism of inhibition involving the formation of a quinonimmonium methide intermediate is proposed. The activity of the inhibitors is very sensitive to the nature of the X benzylic substituent. An increased efficiency for the inactivation of human urokinase is observed with the sulfonium salts. The selectivity of the inactivation of u-PA compared to t-PA could be of therapeutical significance in controlling cell proliferation and invasion.
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PMID:New mechanism-based inactivators of trypsin-like proteinases. Selective inactivation of urokinase by functionalized cyclopeptides incorporating a sulfoniomethyl-substituted m-aminobenzoic acid residue. 849 23

A method for the localization of activities of proteases using substrates with 7-amino-3-trifluoromethylcoumarine (AFC) leaving group is described. 0.1 ml of 5-20 mMol solution of the respective substrate (Gly-Pro-AFC, Ala-Pro-AFC, Z-Ala-Arg-Arg-AFC, Z-Gly-Arg-Arg-AFC, Z-Gly-Gly-Arg-AFC, D-Val-Leu-Lys-AFC) in dimethylsulfoxide or dimethylformamide was added to 0.9 ml of 0.1 M Tris-HCl buffer, pH 7.4-7.8 or 0.1 M cacodylate buffer, pH 5-5.5. In the case of Z-Ala-Arg-Arg-AFC (cathepsin B substrate) 15 mM EDTA and 12 mM dithiothreitol were added. 7 mM amiloride or 2 mg/1 ml aprotinin were used as inhibitors with Z-Gly-Gly-Arg-AFC (urokinase substrate) and with D-Val-Leu-Lys-AFC (plasmin substrate). Substrate solutions were mixed with an equal amount of 2% agar solution in distilled water or in the respective buffer the pH of which was adjusted according to the pH optimum of the enzyme to be demonstrated. The agar solution was kept in a water bath at a temperature of 50-60 degrees C. After careful mixing, the substrate solution in agar was poured into a cylindrical vessel closed with a semipermeable membrane (Nephrophan) on which unfixed cryostat sections were mounted. 1-5 mM AFC solution in dimethylsulfoxide or dimethylformamide instead of the substrate was used as the control. Quenched samples of rat kidney and jejunum, biopsies of human jejunal mucosa, and of colorectal and uterine tumors were employed for the preparation of sections. After gelification of the medium in a refrigerator the vessels with sections were incubated in the dark at 37 degrees C for 0.5-several h. The reaction was controlled in a fluorescence microscope with an epiillumination adjusted to the FITC fluorescence and documented. A yellowish green fluorescence depicts sites where AFC was set free (sites with enzyme activity). When the reaction reached the required intensity the membranes were cut off, transferred to glass slides, mounted in glycerol, observed and photographed immediately (due to the solubility of AFC in glycerol). An acceptable cellular localization was achieved. The method with AFC substrates can be recommended for comparative biochemical and histochemical studies of proteases using the same substrate and for cases in which no other reliable procedure for the localization of the respective enzyme activity is available (e.g. urokinase, plasmin).
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PMID:The use of substrates with 7-amino-3-trifluoromethylcoumarine (AFC) leaving group in the localization of protease activities in situ. 873 6

To understand digestive and invasive mechanisms employed by blood-feeding parasitic copepods, extracts of Phrixocephalus cincinnatus were assayed for specific proteolytic enzyme activity. Intact parasites were dissected into the 3 major body regions, cephalothorax (CT), genital segment (GS), and eggstrings (ES), and homogenized in ice-cold 1% Triton X-100 (v/v) in water. Protease activity in each body region was assayed using several synthetic fluorogenic peptide substrates. The greatest activity was detected when samples were incubated with carbobenzoxy-phenylalanyl-arginyl-7-amido-4-methylcoumarin (CBZ-phe-arg-NHMec) in the presence of cysteine or reducing agents. Substrate specificity, pH profile, and inhibitor sensitivity indicated that the proteolytic enzyme(s) belonged to the cysteine class of endopeptidases and were most similar to mammalian cathepsins L, B, and H, respectively. Intense protease activity was also detected with carbobenzoxy-glycyl-L-prolyl-L-arginine-7-amido-4-methylcoumarin (CBZ-gly-pro-arg-NHMec), a substrate for the serine proteases, plasmin and thrombin. Substrate gel electrophoresis revealed intense gelatinolytic activity in all body regions; however, the ES extract presented a pattern different from that of the adult body, suggesting that distinct proteolytic enzymes are expressed during development. Gelatinolytic activity was inhibited at low pH and in the presence of serine protease inhibitors but not cysteine protease inhibitors. Collectively, the results indicate the presence of 2 major classes of proteolytic enzymes, cysteine and serine proteases. Differential expression of these proteases may be important for the successful completion of the parasite's life cycle, as well as survival of the adult.
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PMID:Proteolytic enzymes in the blood-feeding parasitic copepod, Phrixocephalus cincinnatus. 905 89

The mouse is the most commonly used species for in vivo studies on angiogenesis related to tumor development. Yet, to the best of our knowledge, very few reports on the in vitro interaction of the angiogenic basic fibroblast growth factor (bFGF) with mouse endothelial cells are available. Three mouse endothelial cell lines originated from aorta (MAECs), brain capillaries (MBECs), and heart capillaries (MHECs) were characterized for endothelial phenotypic markers, in vivo tumorigenic activity, and the capacity to respond in vitro to bFGF. These cells express angiotensin-converting enzyme, acetylated LDL receptor, constitutive endothelial nitric oxide synthase, and vascular cell adhesion molecule-1 and bind Griffonia simplicifolia-I lectin. When injected subcutaneously in nude mice, MAECs induced the appearance of slow-growing vascular lesions reminiscent of epithelioid hemangioendothelioma, whereas MBEC xenografts grew rapidly, showing Kaposi's sarcoma-like morphological features. No lesions were induced by injection of MHECs. MAECs, MBECs, and MHECs expressed both low-affinity heparan sulfate bFGF-binding sites and high-affinity tyrosine kinase receptors (FGFRs) on their surfaces. In particular, MAECs expressed FGFR-2/bek mRNA, whereas microvascular MBECs and MHECs expressed FGFR-1/flg mRNA. Accordingly, bFGF induced a mitogenic response and the phosphorylation of extracellular signal-regulated kinase-2 in all the cell lines. In contrast, upregulation of urokinase-type plasminogen activator expression was observed in bFGF-treated microvascular MBECs and MHECs but not in MAECs. Also, bFGF-treated MBECs and MHECs but not MAECs invaded a three-dimensional fibrin gel and formed hollow, capillary-like structures. The relevance of the modifications of the fibrinolytic balance of mouse microvascular endothelium in bFGF-induced angiogenesis was validated in vivo by a gelatin-sponge assay in which the plasmin inhibitors tranexamic acid and epsilon-aminocaproic acid given to mice in the drinking water inhibited neovascularization induced by the growth factor. In conclusion, differences in response to bFGF exist between large-vessel MAECs and microvascular MBECs and MHECs. Both in vitro and in vivo data point to a role of the profibrinolytic phenotype induced by bFGF in microvascular endothelial cells during mouse angiogenesis. Our observations make these endothelial cell lines suitable for further studies on mouse endothelium during angiogenesis and in angioproliferative diseases.
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PMID:Basic fibroblast growth factor-induced angiogenic phenotype in mouse endothelium. A study of aortic and microvascular endothelial cell lines. 910 63

Several peptides were isolated from the diafiltration retentate, prepared using 10 kDa membranes, of the water-soluble extract from a commercial mature Cheddar cheese and identified by amino acid sequencing and mass spectrometry. Most of the peptides were from the N-terminal half of the beta-casein, but peptides from alpha s1- and alpha s2-caseins were also identified; the extract also contained alpha-lactalbumin. Identified peptides showed the important role played by lactococcal cell envelope proteinases in the degradation of primary proteolytic products from alpha s1- and beta-caseins, produced by chymosin and plasmin respectively. Plasmin seemed to be involved in the hydrolysation of alpha s2-casein. Several phosphopeptides were identified and the action of phosphatase on these peptides was evident.
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PMID:Isolation and identification of further peptides in the diafiltration retentate of the water-soluble fraction of Cheddar cheese. 927 58

Amiloride is an inhibitor of urokinase plasminogen activator (uPA), an essential component of the plasminogen/plasmin enzyme system. Inhibition of uPA prevents the conversion of plasminogen to tumor cell surface bound plasmin which is required for initiation of the metastatic process. MATB rat mammary cancer cells were introduced into the jugular venous system of 80 Fisher 344 female rats. Amiloride at high and low dosages was administered in the drinking water at the time of, prior to or several days following the tumor cell inoculation and continued daily for 10 days post inoculation. Control rats were maintained on water alone. The middle lobe of the right lung was examined microscopically for numbers of metastases. Suppression of metastases was significant at high amiloride dosages in all groups, and at low dosage when administered prior to inoculation. We conclude that amiloride suppresses induced metastases of rat mammary cancer, the effect being dose- and time-dependent.
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PMID:Time and dose dependency of the suppression of pulmonary metastases of rat mammary cancer by amiloride. 962 14

Ouabainlike factors are thought to be a kind of important modulators of salt and water metabolism in essential hypertension. We purified the binding-protein of ouabain (OBP) from human plasma. The amino-terminal sequence of OBP from human plasma, (NH2-TLGQPREPQVYTLPPXREEM-), indicated that OBP is the carboxy-terminal fragment (14.4 kDa by SDS-PAGE) from T218 of IgG2 heavy chain and from A221 of the IgG1 heavy chain constant region. Moreover, plasmin-cleaved Fc fragment (pFc) of IgG possessed the ouabain-binding activity by the gel-filtration method of pFc and authentic ouabain mixture, whereas neither intact, aggregate, nor papain-cleaved Fc fragment did. The amino-terminal sequence of pFc was NH2-THTXPPXPAPELLGGPXVFL-, and this sequence corresponded to the T105 to L125 fragment of the IgG1 heavy chain constant region. The growth of cultured THP-1 cells were arrested in the dose-dependent manner by ouabain, which was inhibited by the addition of 20 microg/mL of pFc. These results suggested that plasmin-cleaved Fc of human IgG is one of the binding protein of ouabain/ouabainlike factor(s) in human plasma.
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PMID:Purification and characterization of ouabain-binding protein in human plasma. 968 24

A study was undertaken to compare the chemical and sensory characteristics of Abondance cheeses made with milk from animals grazing areas within the same highland pasture, but with different predominant plants. Nine cheeses made during the last 3 d of three successive 7 d periods were evaluated. The animals grazed on the southern side of the highland pasture during the first period (15-21 June), on the northern side during the second period (22-29 June) and returned to the southern side for the third period (30 June-6 July). The gross composition of the cheeses did not vary between periods. 'North' cheeses contained more plasmin, gamma-casein, alpha s1-I-casein and water-soluble N than 'south' cheeses. Both sensory and instrumental measurements indicated that north cheeses were less firm, stickier and more easily fractured than south cheeses. North cheeses were also more salty, bitter and persistent. Their overall aroma was more intense and they had more intense sour, burnt, toasted, fermented vegetable and sweat aromas, but less intense toffee, exotic fruit and acid milk aromas. The texture differences noted between the cheeses from milk produced on the two areas may come from differences in primary proteolysis, partly due to different amounts of plasmin and plasminogen in milk and in cheeses. The aroma differences were related to differences in volatile compounds. Some compounds had a microbial origin, while some others may have come from the pasture.
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PMID:Influence of the composition of Alpine highland pasture on the chemical, rheological and sensory properties of cheese. 1061 56

The interaction of plasminogen, tissue plasminogen activator (t-PA) and urokinase with a clinical strain of Helicobacter pylori was studied. Plasminogen bound to the surface of H. pylori cells in a concentration-dependent manner and could be activated to the enzymatic form, plasmin, by t-PA. Affinity chromatography assays revealed a plasminogen-binding protein of 58.9 kDa in water extracts of surface proteins. Surface-associated plasmin activity, detected with the chromogenic substrate CBS 00.65, was observed only when plasminogen and an exogenous activator were added to the cell suspension. The two physiologic plasminogen activators, t-PA and urokinase, were also shown to bind to and remain active on the surface of bacterial cells. epsilon-Aminocaproic acid caused partial inhibition of t-PA binding, suggesting that the kringle 2 structure of this activator is involved in the interaction with surface receptors. The activation of plasminogen by t-PA, but not urokinase, strongly depended on the presence of cells and a 25-fold enhancer effect on the initial velocity of activation by t-PA compared to urokinase was established. Furthermore, a relationship between cell concentration and the initial velocity of activation was demonstrated. These findings support the concept that plasminogen activation by t-PA on the bacterial surface is a surface-dependent reaction which offers catalytic advantages.
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PMID:A study of the interaction between Helicobacter pylori and components of the human fibrinolytic system. 1097 31


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