Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.21.4 (trypsin)
42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An inhibitor of factor XIIa has been purified to homogeneity from bovine plasma. The purification steps included precipitation of contaminating proteins with polyethylene glycol and chromatography on DEAE-cellulose, Affi-Gel blue, and immobilized wheat germ lectin. The apparent molecular weight of the XIIa inhibitor (called INH1) was 85,000, reduced, and 92,000, nonreduced, by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The extinction coefficient (E0.1%(280)) of INH1 is 1.3, and the protein contains 17.7% carbohydrate. Purified antibody to INH1 raised in either rabbits or chickens formed a precipitin line of identity with purified INH1 and a component of bovine plasma, but there was no reaction with purified human inhibitors or with any component of human plasma. INH1 inhibits bovine and human XIIa, bovine and human C1-esterase, and human kallikrein, but does not inhibit bovine kallikrein, bovine trypsin, human plasmin, or human thrombin. This activity is similar to that of C1-inhibitor but different from antithrombin III, alpha 2-antiplasmin, or alpha 1-protease inhibitor. INH1 at a physiological concentration (0.47 microM) causes rapid inactivation of XIIa. The two molecules react in a 1:1 stoichiometry with a second-order rate constant of 1.23 X 10(6) M-1 min-1.
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PMID:Isolation and characterization of an inhibitor of factor XIIa from bovine plasma. 311 62

In our previous research, we found that the level of the plasminogen activity in the plasma from Duchenne-type patients with progressive muscular dystrophy was higher than of the normal boys, though the level of the plasmin inhibitors was lower. Therefore, in the present study, we investigated the differences in the fractions of plasmin inhibitors. The subjects were nine patients (the average age being 17.1 years) who had been diagnosed, by clinical and biochemical tests, as having PMD; serving as controls were normal boys (the average age being 15 years), the patients' mothers, and the mothers of the normal boys. The plasmin inhibitors were separated from plasma using lysine-Sepharose columns according to the method of Urita et al. The determination was performed based on the method of Aoyagi et al. and an immunoreactive assay. The results were as follows: (1) No significant differences were seen between patients with PMD and control subjects with respect to either alpha 1-antichymotrypsin, antithrombin III, and alpha 1-antitrypsin or alpha 2-macroglobulin and inter-alpha-trypsin inhibitors. These results suggested that the low level of plasmin inhibitors in patients was due to the low activity of the C1 inactivator. (2) The patients with PMD showed lower values than the normal boys in the levels of C1 inactivator in plasma; similarly, the mothers of these patients showed lower values than the normal mothers.
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PMID:Plasma plasmin inhibitors in Duchenne-type progressive muscular dystrophy. 316 Mar 43

125I-labeled human antithrombin III (125I-AT III).protease complexes are specifically bound to both cultured human skin fibroblast (HSF) cells and adult bovine aortic endothelial (ABAE) cells; however, there is a significant difference in the rate and degree of metabolism of the complexes by these two cell types. HSF cells appear to internalize the complexes at a rate of about 2.5 pmole/1 X 10(6) cells/h and subsequently degrade them at a rate of 0.6 pmole/1 X 10(6) cells/h. ABAE cells internalize and degrade the complexes at rates approximately 100 and 30 times lower, respectively. Neither cell type interacts with free 125I-AT III but only with its combined form with either thrombin or trypsin. These data indicate the major role of HSF cells in the removal of AT III.protease complexes from extravascular spaces in the body, in contrast to the inert vascular surface with regard to AT III.protease complexes provided by the vascular endothelium.
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PMID:Comparative study of antithrombin III.protease complex metabolism by fibroblasts and vascular endothelial cells. 351 18

The anticoagulant activity of heparin is dependent on its affinity for antithrombin III (AT III) and on its molecular weight. In contrast, heparin fractions differing in these respects are equally effective inhibitors of the human complement system in vitro. In this study we designed and evaluated a model to investigate the effects of different heparin fractions on a complement dependent inflammation. Locally administered heparin, in a dose-dependent manner, inhibited the flare, itch and wheal responses induced by intradermal injection of heat-aggregated human IgG (HAGG). These reactions were also inhibited by the antihistamine mepyramine, favouring the view that HAGG activates complement and that the observed inflammatory response is mediated by anaphylatoxin liberation of histamine. Similar cutaneous reactions induced by trypsin, which can generate C3a and C5a by proteolysis of C3 and C5, the histamine liberator compound 48/80 or histamine were inhibited by mepyramine but not by heparin. Thus it is strongly suggested that heparin inhibits the HAGG induced reactions by modulating the early pre-C3 steps of complement activation. On a weight basis heparin fractions differing in AT III-affinity or in average molecular weight (5,000 and 16,000 D) were equally potent modulators of the HAGG-induced inflammation. We conclude that heparin can inhibit an apparently complement-dependent inflammation irrespective of its AT III-affinity or of its size, and suggest that a heparin with low anticoagulant activity could be of value as a modulator of inflammation and should be useful in investigating the consequences of complement inhibition in inflammation.
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PMID:Inhibition of complement dependent experimental inflammation in human skin by different heparin fractions. 373

Bovine corneal endothelial (BCE) cells have been shown to specifically bind, internalize and degrade antithrombin III (AT III).protease complexes as well as thrombin. Previous studies have indicated that chloroquine has no effect on the internalization of thrombin or other cell surface-bound ligands, but it inhibits their subsequent degradation. In contrast, the present study demonstrates the unique inhibitory effect of chloroquine on the internalization of 125I-AT III.trypsin complex by BCE cultures. Similarly, the primary amines, monodansylcadaverine and methylamine, inhibit the internalization of 125I-AT III.trypsin complex, but not the internalization of 125I-thrombin. The various amines used in this study revealed: (1) differences in the process of cellular binding and internalization between AT III.protease complex and thrombin, although the degradation of both internalized ligands proceed in an analogous manner; and (2) the unique sensitivity to chloroquine of 125I-AT III.trypsin complex internalization by cultured cells. These results might indicate that AT III.protease complexes are internalized via a distinct receptor and/or a different mechanism from thrombin.
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PMID:Chloroquine and primary amines inhibit the internalization of antithrombin III.trypsin complex in cultured cells. 390 4

Cysteine protease inhibitors that specifically reacted with several cysteine proteases were found in KSCN extract of human melanoma tissue. From 30 gm of the tissue, approximately 593.5 U inhibitor was obtained. The inhibitors were adsorbed on a papain-Sepharose column and could be eluted with 10 mmol/L phosphate buffer, pH 6.0, containing NaCl or KCl, or with 20 mmol/L acetate buffer, pH 4.0, containing KSCN. They revealed a strong inhibitory activity for cysteine proteases such as ficin, papain, and cathepsin B, but did not react with cysteine protease bromelain or serine protease trypsin. No immunologic relationship was confirmed between the inhibitor and other well-known plasma inhibitors such as alpha 1-antitrypsin, alpha 2-macroglobulin, alpha 1-antichymotrypsin, antithrombin III, C1-in-activator, and alpha 2-plasmin inhibitor. With Sephadex G-100, two main peaks of molecular weight 40,000 and 10,000 were detected in the KSCN extract of the human melanoma tissue. However, the inhibitors revealed three molecular weights of 10,000, 25,000, and 80,000 when estimated by Sephadex G-100 gel filtration after papain-Sepharose affinity chromatography. On the other hand, the molecular weights of the inhibitors changed to two peaks of 25,000 and 10,000 on rechromatography with a papain-Sepharose column.
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PMID:Cysteine protease inhibitors isolated from human malignant melanoma tissue. 393 99

The present paper describes chemical and functional properties of protease nexin, a serine protease inhibitor released from cultured human fibroblasts. It is shown that protease nexin is actually synthesized by fibroblasts and represents about 1% of their secreted protein. Analysis of the amino acid composition of purified protease nexin indicates that it is evolutionarily related to antithrombin III and heparin cofactor II. Protease nexin contains approximately 6% carbohydrate, with 2.3% amino sugar, 1.1% neutral sugar, and 3.0% sialic acid. The Mr calculated from equilibrium sedimentation analysis is 43,000. Protease nexin is a broad specificity inhibitor of trypsin-like serine proteases. It reacts rapidly with trypsin (kassoc = 4.2 +/- 0.4 X 10(6) M-1 s-1), thrombin (kassoc = 6.0 +/- 1.3 X 10(5) M-1 s-1), urokinase (kassoc = 1.5 +/- 0.1 X 10(5) M-1 s-1), and plasmin (kassoc = 1.3 +/- 0.1 X 10(5) M-1 s-1), and slowly inhibits Factor Xa and the gamma subunit of nerve growth factor but does not inhibit chymotrypsin-like proteases or leukocyte elastase. In the presence of heparin, protease nexin inhibits thrombin at a nearly diffusion-controlled rate. Two heparin affinity classes of protease nexin can be detected. The present characterization pertains to the fraction of protease nexin having the higher affinity for heparin. The low affinity material, which is the minor fraction, is lost during purification.
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PMID:Protease nexin. Properties and a modified purification procedure. 399 57

The antiproteinase activities against trypsin, chymotrypsin, elastase, papain and rat leucocyte proteinases were determined in plasma from control and Morris hepatoma-bearing rats. Bovine trypsin and chymotrypsin were similarly inhibited by the two types of plasma whereas porcine pancreatic elastase, papain and rat leucocyte neutral proteinases were more efficiently inhibited by plasma from tumour-bearing rats. The increased plasma concentrations of some proteinase inhibitors, as determined by rocket immunoelectrophoresis, are suggested to be responsible for the observed differences in inhibition. The highest increases in plasma of tumour-bearing rats were observed for alpha 2-macroglobulin and alpha 1-acute-phase globulin. The synthesis and secretion of six proteinase inhibitors: antithrombin III, alpha 1-proteinase inhibitor, alpha 1-macroglobulin, alpha 2-macroglobulin, alpha 1-acute-phase globulin and haptoglobin, as well as albumin, were measured in tissue slices from rat liver and Morris hepatoma after incubation with [14C]leucine. Local inflammation inflicted upon the tumour-bearing rats increased formation of acute-phase proteins in liver slices but not in hepatoma slices.
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PMID:Plasma proteinase inhibitors in Morris hepatoma-bearing rats: changes in the blood level and synthesis in tissue slices. 407 27

Unactivated partial thromboplastin antecedent (PTA) has been purified by sequential chromatography of plasma on quaternary aminoethyl Sephadex, sulphoprophyl Sephadex, Sephadex G-150, and passage over an anti-IgG immunoadsorbant. The preparation gave a single band after alkaline disc gel electrophoresis, sodium dodecyl sulfate (SDS) gel electrophoresis and isoelectric focusing in acrylamide gels and was found to have a mol wt of 175,000 by gel filtration, 163,000 by SDS gel electrophoresis, and an isoelectric point of 8.8-9.4 (peak 9.0-9.1). Pre-PTA was activated directly by activated Hageman factor or by Hageman factor prealbumin fragments. Its coagulant activity was inhibited by DFP, soybean trypsin inhibitor and trasylol but not by lima bean trypsin inhibitor or ovomucoid trypsin inhibitor indicating that activated PTA possesses the same inhibition profile utilizing these reagents as does plasma kallikrein. A major plasma inhibitor of activated PTA was found to be a 65,000 mol wt alpha-globulin which was isolated free of alpha(1)-chymotrypsin inhibitor, inter alpha-trypsin inhibitor, alpha(2)-macroglobulin, and the other known inhibitors of activated PTA, the activated first component of complement (C1 INH), and antithrombin III. Its physicochemical properties were identical to alpha(1)-antitrypsin, and it was absent in alpha(1)-antitrypsin-deficient plasma thereby identifying this PTA inhibitor as alpha(1)-antitrypsin.
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PMID:Substrates of Hageman factor. I. Isolation and characterization of human factor XI (PTA) and inhibition of the activated enzyme by alpha 1-antitrypsin. 454 83

Examination of the peritoneal exudates of 12 patients with acute pancreatitis revealed high activities of pancreatic lipase and amylase. The immunologic levels of the plasma-derived inhibitors alpha 1-antitrypsin, antithrombin III and alpha 2-macroglobulin in the peritoneal exudates were not markedly different from those of the plasma. However, the inhibitory capacity of alpha 2-macroglobulin, the main inhibitor of human pancreatic trypsin in the exudate, was almost completely depleted when measured by an enzymatic method. Furthermore, spontaneous fibrinolysis occurred in 6 out of 13 exudates applied to plasminogen-free fibrin plates, indicating the presence of free proteinase. This fibrinolytic activity might be inhibited by exogenous alpha 2-macroglobulin or aprotinin (Trasylol, Bayer AG).
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PMID:Proteinases and inhibitors in plasma and peritoneal exudate in acute pancreatitis. 608 67


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