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)

Biopsy specimens of human gastric mucosa, maintained in culture for 7 days in the absence of serum, released a collagen-degrading enzyme into the medium. The yield of active enzyme reached a maximum after 2-3 days, and viable tissue, capable of protein synthesis, was essential for its production. 2. At 25 degrees C the enzyme attacked undenatured collagen in solution, resulting in a 55% loss of specific viscosity and producing the two products TCA and TCB characteristic of neutral-collagenase action. 3. Electron microscopy of segment-long-spacing crystallites of these reaction products showed the exact cleavage locus of the collagen molecules to be between bands 43 and 44 (I-43). The larger TCA and smaller TCB products were fragments representing 77 and 23% respectively of the length of the collagen molecule. 4. Optimal enzyme activity was observed over the pH range 7.5-8.5 and a mol.wt. of approx. 38000 was derived from gel-filtration studies. 5. The enzyme was shown to be inhibited by the human serum proteins alpha2-macroglobulin and a smaller component of mol.wt. approx. 40000; alpha1-anti-trypsin was not inhibitory. 6. EDTA, 1, 10-phenanthroline, cysteine and dithiothreitol all inhibited collagenase activity. 7. The gastric enzyme has properties similar to other well characterized collagenases, but differences exist with respect to its molecular size and the site of attack on the collagen molecule.
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PMID:A neutral collagenase from human gastric mucosa. 0 57

The kallikrein inhibitor contents of human and animal plasma were determined with glandular kallikreins [EC 3.4.21.8]. One ml of plasma could inactivate 20-700 kallikrein units (KU). Rat plasma was the most potent and inactivated 230-700 KU. However, no enzyme capable of inactivating kallikrein could be found in this plasma. Two fractions which inhibited hog pancreatic kallikrein, a fraction corresponding to alpha2-macroglobulin and a fraction which was eluted prior to albumin, were separated from rat plasma by Sephadex G-200 gel filtration. The former inhibitor could inhibit hog pancreatic kallikrein action on Nalpha-benzoyl-L-arginine ethyl ester (BAEE) as well as in the dog vasodilator assay. The other inhibitor was partially purified from rat plasma. One mg of the preparation inhibited 67 KU and the hydrolysis of 5.8 micronmoles/min of BAEE by hog pancreatic kallikrein [EC 3.4.21.8]. The inhibitor also inhibited other glandular and plasma kallikreins, trypsin [EC 3.4.21.4], alpha-chymotrypsin [EC 3.4.21.1], etc. The optimal pH of the inhibitor was 7.5-8. The inhibitor was unstable below pH 5, and was destroyed by heating at temperature above 60 degrees. The isoelectric point of the inhibitor was determined by Ampholine focusing to be 4.4, and its molecular weight was estimated to be 73,000 by Sephadex G-100 and G-150 filtrations. Several experimental results suggested that this inhibitor differed from alpha1-antitrypsin.
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PMID:Kallikrein inhibitors in rat plasma. 1 35

Three phenotypical variants of normal human serum alpha2-macroglobulin revealed by immunoelectrophoresis and specific antibodies obtained in rabbits are presented. The variants are characterized by differences in electrophoretic mobility: one being fast, one slow, and one of an intermediate rate. To find out possible differences with respect to the effect of the trypsin and chymotrypsin on the three variants, they were treated with the enzymes before immunoelectrophoresis. Migration was accelerated in all cases, after complexing with the enzymes, but the differences in the relative positions of the variants were maintained. The trypsin- and chymotrypsin-binding capacities of these three forms seem to differ, as suggested by the results presented in this report.
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PMID:Variants of normal human alpha2-macroglobulin. Immunoelectrophoresis and enzyme-binding effect. 5 Feb 67

Pancreatitis was induced by injection of autologous bile into the main pancreatic duct of dogs. An initial fall in blood pressure was accompanied by appearance of large quantities of active trypsin, chymotrypsin, and elastase in pancreatic exudate with full saturation of protease inhibitors. The enzymes soon appeared in ascitic fluid and lymph, but only in the form of complexes with alpha1-antitrypsin, and alpha2-macroglobulin. No such complexes were detected in venous blood indicating short half-life in the circulation. These studies confirm the release of pancreatic enzymes during bile-induced pancreatitis, and quantify an important protective role for plasma protease inhibitors in this situation.
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PMID:Release of proteolytic enzymes in bile-induced pancreatitis in dogs. 5 Sep 58

Antithrombin activity has been identified in intact washed human platelets. An apparent activity was demonstrated at platelet concentrations above 0.31 X 10(9)/ml, when platelet suspensions were incubated with 2.0 NIH units/ml of thrombin. Neither red cells nor white cells revealed antithrombin activity. No significant loss of the platelet antithrombin activity was observed after ten successive washings or after treatment of platelets with antibodies to antithrombin III or alpha2-macroglobulin. Almost the same amount of antithrombin activity as normal platelets was demonstrated in the platelets from an afibrinogenemic patient. Pre-treatment of platelets with trypsin, papain, and neuroaminidase reduced the activity significantly, whereas lipase was without effect. The platelet antithrombin reacted with thrombin in less than 3 seconds, and this rapid reaction of platelet antithrombin was different from that of plasma antithrombin III or fibrinogen. The thrombin-like clotting activity of ancrod was inhibited by fibrinogen but not platelets. Also, unlike plasma antithrombin III or fibrinogen, brief exposure to heat (56 degrees C or 60 degrees C) reduced considerable amounts of platelet antithrombin activity. These results suggest that platelets possess a specific antithrombin with different characteristics from other known antithrombins.
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PMID:Antithrombin activity of intact human platelets. 5 97

Four protease inhibitors have been identified in human serum and methods for their isolation are described. After removal of the euglobulin fraction, serum was submitted to ion exchange chromatography and gel filtration, and fractions were tested for inhibition of the lysis of plasminogen-deficient fibrin clots by plasmin, trypsin and elastase. In addition inhibitors of plasminogen activation were sought by studying the effects of separated fractions on the lysis of plasminogen-rich fibrin clots by urokinase. Examination by immunophoresis showed that three of the separated inhibitors were alpha2-macroglobulin, alpha1-antitrypsin and inter-alpha-trypsin inhibitor. The fourth antiprotease was a powerful inhibitor of both urokinase-induced and plasmin-induced clot lysis, and was identified as an inter-alpha-globulin from its electrophoretic mobility in agarose gels.
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PMID:Serum inhibitors in fibrinolysis. 5 65

Proteinases in plasma bind largely to alpha1-antitrypsin and alpha-macroglobin. The latter is represented in humans by alpha2-macroglobulin and in the rabbit by alpha2-macroglobulin and alpha1-macroglobulin. There is a selective and rapid uptake of proteinase-macroglobulin complexes by rabbit alveolar macrophages. It was found that complexes of labelled trypsin or subtilopeptidase A with rabbit alpha1-antitrypsin do not become similarly associated with rabbit alveolar macrophages. Moreover, proteinase-alpha1-antitrypsin complexes failed to inhibit the uptake of labelled proteinase-macroglobulin complexes. Thus, the interaction with macrophages of proteinase-macroglobulin complexes represents a pathway of proteinase metabolism distinct from that involving proteinase bound to alpha1-antitrypsin.
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PMID:The role of alpha1-antitrypsin and alpha-macroglobulins in the uptake of proteinase by rabbit alveolar macrophages. 5 12

An inhibitor of neutral subtilopeptidase [EC 3.4.24.4] was purified from porcine serum by salting out with (NH4)2SO4, chromatography on anion exchange sephadex, gel filtration with Sepharose 6B, and isoelectric focusing. The preparation was homogeneous by electrophoretic and ultracentrifugal criteria, and was shown to be a glycoprotein with a molecular weight of 740,000. It inhibited the caseinolytic activities of thermolysin, subtilisin, trypsin [EC 3.4.21.4], and alpha-chymotrypsin [EC 3.4.21.1] as well as that of neutral subtilopeptidase by an equimolar binding to those proteolytic enzymes. SDS-polyacrylamide gel electrophoresis after reduction with beta-mercaptoethanol indicated that the inhibitor was made up of four subunit monomers having a molecular weight of 190,000. From comparisons of its physiocochemical and inhibitory properties with those of well-investigated plasma proteins, the inhibitor was identified as alpha2-macroglobulin. On treatment of the inhibitor with neutral subtilopeptidase, a protein with a molecular weight of 95,000 appeared after treatment with SDS and beta-mercaptoethanol, suggesting that a peptide bond susceptible to the enzyme exists near the mid-point of the subunit chains.
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PMID:A neutral subtilopeptidase inhibitor from porcine serum some evidence for alpha2-macroglobulin. 5 60

An inactive collagenase was harvested from both serum-free and serum-supplemented fibroblast monolayer cultures in periods of active collagen synthesis. The latent collagenase did not hydrolyze collagen and did not bind the potent collagenase inhibitor alpha2-macroglobulin. Activation with trypsin imparted to the enzyme the ability to hydrolyze collagen at neutral pH in a typical manner and to form an inhibited complex with alpha2-macroglobulin. The molecular weights, determined by calibrated gel filtration, were 78,000 and 60,000 for the latent and active enzymes, respectively. The data indicate that collagenase is released from the cells in inactive form, as a zymogen.
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PMID:Synthesis and release of procollagenase by cultured fibroblasts. 5 61

Porcine plasmin (EC 3.4.21.7) is obtained from plasminogen activated by human urokinase. This enzyme can bind, in an equimolecular ratio, to an alpha2-macroglobulin isolated from porcine serum. The number of active sites of plasmin has been determined through a burst titration of nitroaniline during the presteady-state hydrolysis of an amide substrate (N-alpha-carbobenzoxy-L-arginine-p-nitroanilide). The kinetic constants relative to a very sensitive ester substrate (N-alpha-carbobenzoxy-L-lysine nitrophenylester) hydrolysis have been measured. The binding of plasmin to alpha2-macroglobulin results in a complete inhibition of proteolytic activity, a reduction of active sites number and a decrease of esterolytic activity towards this substrate. In the complex, the residual activity (about 60%) is protected from protein inhibitors. Absorbance difference spectra show that 1 mol of alpha2-macroglobulin binds 1 mol of plasmin and 2 mol of trypsin. When plasmin is first bound to alpha2-macroglobulin, only 1 mol of trypsin can gain access tothe second site without removing the plasmin, showing that a steric hindrance is implicated in the inhibition performed by alpha2-macroglobulin binding.
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PMID:[Study of the complex between porcine plasmin and alpha2-macroglobulin (author's transl)]. 5 8


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