Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0272170 (SDS)
 50,377 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A recently discovered human plasma protein, tetranectin (TN), which has previously been demonstrated immunohistochemically within various endocrine tissues, was in this study identified in an additional number of epithelial and mesenchymal cells by two polyclonal antibodies and one monoclonal using the conventional immunoperoxidase staining technique and a modification of the CLONO-GLAD procedure. TN was found in endothelial and epithelial tissues, particularly in cells with a high turn-over or storage function such as gastric parietal and zymogenic cells, absorptive surface epithelium of the small intestine, ducts of exocrine glands and pseudostratified respiratory epithelium. Also mesenchymal cells produced a TN positive staining reaction, which was most conspicuous in mast cells, but also present in some lymphocytes, plasma cells, macrophages, granulocytes, striated and smooth muscle cells and fibroblasts. SDS-PAGE and Western blotting analysis of cultured human embryonal fibroblasts (WI-38) showed that the cells besides TN contain another protein with a molecular weight of 82,000. As this protein, however, reacted with our affinity purified antibodies it probably represents a precursor of TN or a protein with a molecular weight of approximately 60,000, which is covalently linked to TN. This and the fact that TN shows amino acid sequence homologies to the carboxyterminal part of the asialo-glycoprotein receptor and a cartilage proteoglycan core protein as well a binding affinity to plasminogen points to TN as being part of a larger molecule, which possibly has been cleaved by proteolysis at the cellular site and then passed into the blood, where it polymerizes into a tetramer.
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PMID:Tetranectin immunoreactivity in normal human tissues. An immunohistochemical study of exocrine epithelia and mesenchyme. 267 Aug 45

Incubation of cultured human endothelial cells with 5 mM-dibutyryl cyclic AMP led to an approx. 2-fold increase in tissue-type plasminogen-activator (t-PA) production over a 24 h incubation period. The stimulating effect of dibutyryl cyclic AMP could be explained by the slow liberation of butyrate, as the effect could be reproduced by addition of free butyrate to the medium, but not by addition of 8-bromo cyclic AMP or forskolin, agents known to raise intracellular cyclic AMP levels. With butyrate, an accelerated accumulation of t-PA antigen in the conditioned medium (CM) was observed after a lag period of about 6 h. Increasing amounts of butyrate caused an increasingly stimulatory effect, reaching a plateau at 5 mM-butyrate. The relative enhancement of t-PA production in the presence of 5 mM-butyrate varied among different endothelial cell cultures from 6- to 25-fold in 24 h CM. Such an increase in t-PA production was observed with both arterial and venous endothelial cells. The butyrate-induced increases in t-PA production were accompanied by increased t-PA mRNA levels. Analysis of radiolabelled CM and cell extracts by SDS/polyacrylamide-gel electrophoresis indicated that the potent action of butyrate is probably restricted to a small number of proteins. The accumulation of plasminogen activator inhibitor type 1 (PAI-1) in CM from butyrate-treated cells varied only moderately. In our study of the relationship between structure and stimulatory activity, we found that a straight-chain C4 monocarboxylate structure with a methyl group at one end and a carboxy moiety at the other seems to be required for the optimal induction of t-PA in cultured endothelial cells.
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PMID:Butyrate stimulates tissue-type plasminogen-activator synthesis in cultured human endothelial cells. 282 33

Neutrophils (PMN) are important in the cellular phase of blood fibrino lytic activity (FA). The contribution of monocytes (MC), which have FA, is unclear. To determine the relative roles of these cells to activity in normal blood, we examined, by solid phase radiofibrin assay, FA of normal blood and plasma, and of purified PMN and MC, with and without plasminogen (PLG), mini-plasminogen (mPLG), the other major elastase fragment of PLG, or autologous plasma. PMN alone (0.5 x 10(6)/ml) had striking activity (292 +/- 25 SEM ng fibrin lysed/h; n = 10 normal subjects) while MC alone (0.5 x 10(6)/ml) had mean FA of 32 +/- 4 ng/h, which could be accounted for by contaminating PMN (36 +/- 8 ng/h). Thus, in a 1 h assay (when cellular FA accounts for 70-80% of FA in whole blood), normal numbers of MC (0.5 x 10(6)/ml) had no detectable FA when assayed with PLG or normal plasma. With longer assay times (2-6 h), PLG-dependent (plasminogen activator, PA) activity was demonstrated with mixtures of MC and PLG or plasma. This PA activity was released into the medium and required prior contact of MC and an intact, soluble PLG molecule for PA activity to be detected in medium (suggesting a PLG-MC triggering mechanism), since activity was reduced or absent when MC were exposed to mPLG, the other major elastase fragment of PLG, or solid phase PLG. Exposure of MC to solid phase fibrin did not result in PA release. MC PA activity was little affected by cycloheximide pretreatment, indicating preformed rather than newly synthesized PA. By SDS-PAGE and fibrin zymography, MC extracts revealed a single PA band with features of pro-urokinase (single chain urinary-type PA): Mr 55,000, inhibition by antiurokinase antibody (but not by anti-tPA), and resistance to inhibition by DFP. By ELISA assay, approximate normal monocyte content of this PA (as Mr 55,000 urokinase) was 0.03 fg (3.3 x 10(8) molecules) per cell.
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PMID:Fibrinolytic activity of normal human blood monocytes. 292 5

An investigation of the physical status of fibrinogen that has been adsorbed to glass and then eluted has been conducted. Exposure of Kabi fibrinogen to glass was carried out using a glass bead column experiment. The fibrinogen was eluted sequentially, first by 1 M Tris and then by SDS. The initially eluted fibrinogen showed considerable degradation (SDS polyacrylamide gel electrophoresis) while the later fractions were less degraded. Fibrinogen purified by chromatography on either DEAE-cellulose or Sepharose-lysine to remove plasminogen was less degraded. When purified plasminogen was added to fibrinogen, degradation of column eluates was very extensive in all eluted fractions. These results are interpreted in terms of a surface-mediated activation of plasminogen to plasmin followed by fibrinogenolysis. Although such an effect remains to be demonstrated as a general property of surfaces, it is speculated that surfaces may vary in their activation of fibrinolysis as well as their activation of clotting, and that maximization of fibrinolysis is a worthwhile goal in the development of blood-compatible surfaces.
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PMID:Degradation of adsorbed fibrinogen by surface-generated plasmin. 293 35

An anticoagulant enzyme, Cerastase F-4, from the venom of Cerastes cerastes was purified to homogeneity and was characterized (1). In the present report the mode of its fibrinogenolytic and fibrinolytic actions, and its effects on some other blood coagulation factors are described. Cerastes F-4 was shown to readily hydrolyze the alpha A chain of fibrinogen followed by the hydrolysis of the beta B chain. The gamma-chain was relatively resistant to hydrolysis. It also degrades the three chains of fibrin at different rates. The degradation products of the two substrates shown on SDS-polyacrylamide gel were quite different from those produced by plasmin, indicating different sites of cleavage by the enzyme. Using specific chromogenic substrates, Cerastase F-4 seems not to show thrombin-like, plasmin-like, kallikrein-like, antithrombin, or antiplasmin actions. Also, it does not activate prothrombin or plasminogen but degrades both of them slowly. It is concluded that the anticoagulation property of the purified enzyme, Cerastase F-4, is due to its destruction of fibrinogen.
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PMID:Mechanism of the anticoagulant, Cerastase F-4, isolated from Cerastes cerastes (Egyptian sand viper) venom. 293 87

The rate of plasmin-catalyzed Glu-plasminogen to Lys-plasminogen conversion was faster in the presence of fibrin than in its absence when assayed by SDS-polyacrylamide gel electrophoresis followed by quantification of stained bands by densitometer. Experiments with the isozymes Glu-plasminogen I and Glu-plasminogen II showed that plasmin-catalyzed formation of Lys-plasminogen II was especially facilitated in the presence of fibrin.
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PMID:Release of N-terminal peptides from Glu-plasminogen by plasmin in the presence of fibrin. 293 88

Tissue plasminogen activator was treated with Sepharose-bound trypsin or chymotrypsin. Trypsin rapidly converted the one-chain activator to the two-chain form. This caused a marked increase in the amidolytic activity, while plasminogen activation initially increased but then decreased again. SDS/polyacrylamide gel electrophoresis in combination with [3H]diisopropylfluorophosphate active-site labeling revealed that after the conversion to the two-chain activator a minor cleavage occurred in the B chain, while the A chain was substantially degraded. Chymotrypsin caused a marked decrease in both amidolytic activity and plasminogen activation. SDS/polyacrylamide gel electrophoresis under reducing conditions revealed that two pairs of new bands had appeared, with Mr or about 50,000/52,000 and 17,000/20,000 respectively. N-terminal sequence analysis identified cleavage sites at peptide bonds 420-421 and 423-424. These bonds are located in a region of the activator which is homologues to the segments of trypsin and chymotrypsin, where autocatalytic cleavages occur during their activations. However, treatment of two-chain activator with chymotrypsin had markedly less effect on plasminogen activation and amidolytic activity. By treatment of samples of chymotrypsin-digested one-chain activator with plasmin, amidolytic activity could be largely restored. Thus, chymotrypsin may, by cleaving bonds 420-421 and 423-424, convert the active one-chain activator into an 'inactive' zymogen, which is again 'activated' by plasmin cleavage.
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PMID:Proteolytically induced variations in the enzymatic properties of tissue plasminogen activator. Activations, inactivations and reactivations. 294 92

In a bead column experiment, attempts have been made to identify the proteins adsorbed from plasma onto a glass surface. Proteins adsorbed after a 3-h contact time were eluted sequentially by 1 M tris buffer and SDS. Polyacrylamide gel electrophoresis of eluted proteins showed a multiplicity of components, and not all of these could be identified. Positive identifications were made by immunodiffusion against specific antibodies, band positions on electrophoresis gels, and location of radioactivity in gels when specific radiolabeled proteins were added to plasma. Proteins found were albumin, IgG, fibrinogen, plasminogen, and fibrinogen degradation products (FDP). A major component with an apparent molecular weight of 25,000 remains unidentified. It is unrelated to albumin, IgG, fibrinogen, factor XII, or plasminogen. Adsorbed fibrinogen was less degraded when experiments were performed with plasmas deficient in either plasminogen or factor XII. It is therefore concluded that FDP are formed by activation of adsorbed plasminogen, as was found previously for purified fibrinogen containing a trace of plasminogen. At least part of this activation is potentiated by the contact activation phase of plasma coagulation, in particular activated factor XII.
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PMID:Identification of proteins adsorbed from human plasma to glass bead columns: plasmin-induced degradation of adsorbed fibrinogen. 294 94

A hybrid human cDNA was constructed by splicing of a cDNA fragment of tissue-type plasminogen activator (t-PA), encoding 5'-untranslated, the pre-pro region and amino acids Ser1-Thr263, with a cDNA fragment of urokinase-type plasminogen activator (u-PA), encoding amino acids Leu144-Leu411. The cDNA fragments were obtained from full length t-PA cDNA, cloned from Bowes melanoma poly(A)+ mRNA, and from full length u-PA cDNA, cloned from CALU-3 lung adenocarcinoma poly(A)+ mRNA. The hybrid (t-PA/u-PA) cDNA was expressed in Chinese hamster ovary cells and the translation product purified from the conditioned cell culture media. On SDS-gel electrophoresis under reducing conditions, the protein migrated as a single band with approximate Mr 70,000. On immunoblotting, it reacted both with rabbit antisera raised against human t-PA and against human u-PA. The urokinase-like amidolytic activity of the protein was only 320 IU/mg but increased to 43,000 IU/mg after treatment with plasmin, which resulted in conversion of the single-chain molecule (t-PA/scu-PA) to a two-chain molecule (t-PA/tcu-PA). The specific activity of the protein on fibrin plates was 57,000 IU/mg by comparison with the International Reference Preparation for Urokinase. Both the single-chain hybrid (t-PA/scu-PA) and the two-chain plasmin derivative (t-PA/tcu-PA) bound specifically to fibrin, albeit more weakly than t-PA. The t-PA/tcu-PA hybrid had a higher selectivity for fibrin than tcu-PA, measured in a system composed of a whole human 125I-fibrin-labeled plasma clot immersed in human plasma. Both hybrid proteins activated plasminogen directly with Km = 1.5 microM and k2 = 0.0058 s-1 for t-PA/scu-PA and with Km = 80 microM and k2 = 5.6 s-1 for t-PA/tcu-PA. CNBr-digested fibrinogen stimulated the activation of plasminogen with t-PA/tcu-PA (Km = 0.20 microM and k2 = 1.2 s-1). It is concluded that these t-PA/u-PA hybrid proteins combine, at least to some extent, the fibrin-affinity of t-PA with the enzymatic properties of u-PA (either scu-PA or tcu-PA), which in some assays result in improved fibrin-mediated plasminogen activation.
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PMID:Characterization of a fusion protein consisting of amino acids 1 to 263 of tissue-type plasminogen activator and amino acids 144 to 411 of urokinase-type plasminogen activator. 295 60

Platelets were found to provide a surface for activation of plasminogen by the tissue-type plasminogen activator (t-PA) at an optimum concentration and to potentiate the generation of plasmin by the amidolytic method, fibrin lysis time and fibrin plate method. The effect of platelets on amidolytic activity on S-2251 was due to the potentiating effect of plasminogen activation by t-PA, because it was observed only in the presence of both plasminogen and t-PA. Plasmin generation was also evidenced in the SDS-PAGE profile of the supernatant from a mixture containing t-PA and plasminogen with platelets. These findings suggests that the potentiating activity of platelets on plasminogen activation by t-PA in circulation is one of the causes of fibrinogenolysis during fibrinolytic therapy with a high dose of t-PA. Platelets from patients with various diseases showed different potentiating activity on plasminogen activation by t-PA. The assay of this ability of platelets may be a new tool for evaluating their role in the blood fibrinolytic process.
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PMID:Plasminogen activation by tissue plasminogen activator in the presence of platelets. 297 48


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