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)

A proteolytic activity associated with the microsomal fraction of L-5178Y/Esb tumor cells has been characterized. The enzyme has a molecular weight of 80-90 kD as determined by affinity-labelling with [3H]DFP and SDS-gel electrophoresis. It cleaves ester substrates at the carboxyl position of lysine and arginine and can activate the proenzyme plasminogen. The enzyme is found to be associated with the plasma membranes of high and low metastatic tumor cell lines and is shed in high-molecular-weight form mainly by the high metastatic variant. The pH optimum for esterase and protease activities was 7.5-8.5. Although similar to trypsin in substrate specificity, the enzyme was not inhibited by lima-bean trypsin inhibitor but was inhibited by DFP, PMSF, aprotinin and leupeptin. Partially purified preparations of the protease can alone degrade 125I-labelled endothelial cell extracellular matrix, pointing at the putative role of this enzyme in tumor invasion.
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PMID:Characterization of an extracellular matrix-degrading protease derived from a highly metastatic tumor cell line. 389 58

Adherent monolayer cultures of human blood monocytes, peritoneal macrophages, bone marrow macrophages, and colonic mucosa macrophages were examined for their ability to produce and secrete minactivin, a specific inactivator of urokinase-type plasminogen activator. All except colonic mucosa macrophages produced and secreted appreciable amounts of minactivin, but only blood monocytes were stimulated by muramyl dipeptide (adjuvant peptide) to increase production. The minactivin from each of these populations could be shown to preferentially inhibit urokinase-type plasminogen activator and not trypsin, plasmin, or "tissue"-type plasminogen activator (HPA66). A plasminogen-activating enzyme present in monocyte cultures appeared unaffected by the presence of minactivin and could be shown to be regulated independently by dexamethasone.
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PMID:Minactivin expression in human monocyte and macrophage populations. 392 24

Discrepancies in correlations between fibrinolytic activity and metastatic potential of malignant cells has resulted in speculation on the putative role of plasminogen activators (PA) in cancer. In this report we have compared lymphocyte PA from 40 patients with chronic lymphocytic leukemia (CLL) to normal human B- and T-lymphocytes. Lymphocytes were isolated from peripheral blood by Ficoll-Hypaque centrifugation. The B- and T-cells were further separated on nylon wool columns. Cell PA activity and cell membrane PA were determined using 3H-fibrin-coated plates with added human plasminogen. Lymphocytes did not lyse 3H-fibrin in the absence of plasminogen. Plasminogen-dependent fibrinolytic activities of normal B- and T-lymphocytes were comparable. The addition of protease inhibitors with trypsin or plasmin specificity to lymphocytes significantly inhibited normal PA, thus substantiating the serine protease spectrum of lymphocyte PA. Examination of lymphocytes from greater than 95% of patients with chronic lymphocytic leukemia revealed a marked decrease in lymphocyte and cell membrane PA as compared to normals. No correlation between Stage of CLL and lymphocyte PA was observed. Likewise, an inhibitor of PA in CLL lymphocytes was not detected. The function of PA in normal B-lymphocyte physiology and the potential pathogenetic role of diminished PA in CLL lymphocytes remain to be explored.
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PMID:Plasminogen-dependent fibrinolytic activity in normal human lymphocytes: diminished lymphocyte plasminogen activator in chronic lymphocytic leukemia. 392 13

A persistent puzzle in our understanding of hemostasis has been the absence of hemorrhagic symptoms in the majority of patients with Hageman trait, the hereditary deficiency of Hageman factor (factor XII). One proposed hypothesis is that alternative mechanisms exist in blood through which plasma thromboplastin antecedent (PTA, factor XI) can become active in the absence of Hageman factor. In order to test this hypothesis, the effect of several proteolytic enzymes, among them thrombin, plasma kallikrein, and trypsin, was tested upon unactivated PTA. PTA was prepared from normal human plasma by Ca(3)(PO(4))(2) adsorption, ammonium sulfate fractionation, and successive chromatography on QAE-Sephadex (twice). Sephadex-G150, and SP-Sephadex. The partially purified PTA was almost all in its native form, with a specific activity of 45-70 U/mg protein; the yield was about 10%. It contained no measurable amounts of other known clotting factors, plasmin, plasminogen, nor IgG. Incubation of PTA with trypsin generated potent clot-promoting activity that corrected the abnormally long clotting time of plasma deficient in Hageman factor or PTA but not in Christmas factor. This clot-promoting agent behaved like activated PTA on gel filtration (apparent molecular weight: 185,000) and was specifically inhibited by an antiserum directed against activated PTA. These data suggested that PTA can be converted into its active form by trypsin. PTA was not activated by thrombin, chymotrypsin, papain, ficin, plasmin, plasma kallikrein, tissue thromboplastin, or C. Trypsin converted PTA to its active form enzymatically. Whether trypsin serves to activate PTA in vivo is not yet clear.
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PMID:Partial purification of plasma thromboplastin antecedent (factor XI) and its activation by trypsin. 426 22

The digestion of fibrinogen with various concentrations of trypsin results in the formation of a variety of degradation products. Degradation products formed in this way have been purified by DEAE cellulose column chromatography and their effects on platelet aggregation investigated.TWO METHODS HAVE BEEN USED TO STUDY PLATELET AGGREGATION: a turbidimetric method which assesses platelet aggregation by the ability of adenosine diphosphate (ADP) to clump platelets and a method which assesses platelet adhesiveness by their ability to adhere to glass and to each other (modified Hellem technique, 1960). Three breakdown products produced by trypsin-digested fibrinogen were studied and all showed ;antithrombin' activity: two inhibited platelet aggregation, but one accelerated aggregation in both systems. Another product prepared by digestion of fibrinogen with urokinase-activated plasminogen has been shown to possess the ability to enhance ADP-induced platelet aggregation.
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PMID:McNicol GP,+MACNICOL GP, Douglas AS: Effect of fibrinogen degradation products on platelet aggregation. 575 42

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

When purified human HMW-kininogen was digested by plasmin, its specific antigenic properties were initially enhanced and then gradually destroyed, but its clot-promoting activity (Fitzgerald factor activity) was only slightly decreased. When endogenous serum plasminogen was activated by streptokinase, similar alterations in specific HMW-kininogen antigens and Fitzgerald factor activity occurred. In contrast, trypsin induced increased antigenic properties initially, but readily destroyed the Fitzgerald factor activity and less readily destroyed the specific HMW-kininogen antigenic properties in purified HMW-kininogen and in normal human serum. When normal serum was treated with streptokinase, the antigenic properties shared by HMW and LMW-kininogens were in Sephadex G-200 fractions of lower molecular weight than in the case of untreated serum, but the elution volumes of specific HMW-kininogen antigens and Fitzgerald factor activity were not significantly altered. When prekallikrein-deficient serum was subjected to the same G-200 gel filtration process, there was a broad overlap in the elution volumes of antigens shared by both HMW and LMW-kininogens with specific HMW-kininogen antigenic and coagulant properties, which remained after streptokinase treatment of the serum. Depsite the disparate rates of destruction of the antigenic and clot-promoting portion of HMW-kininogen by proteases these properties did not separate from one another during ion exchange chromatography.
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PMID:Some molecular and functional changes in high molecular weight kininogen induced by plasmin and trypsin. 617 44

The catabolic pathways of streptokinase, plasmin, and activator complex prepared with human plasminogen were studied in mice. (125)I-streptokinase clearance occurred in the liver and was 50% complete in 15 min. Incubation with mouse plasma had no effect on the streptokinase clearance rate. Complexes of plasmin and alpha(2)-plasmin inhibitor were eliminated from the plasma by a specific and saturable pathway. Competition experiments demonstrated that this pathway is responsible for the clearance of injected plasmin. Streptokinase-plasminogen activator complex formed with either (125)I-plasminogen or (125)I-streptokinase cleared in the liver at a significantly faster rate than either of the uncomplexed proteins (50% clearance in <3 min). Streptokinase incubated with human plasma also demonstrated this accelerated clearance. p-Nitrophenyl-p'-guanidinobenzoate-HCl or pancreatic trypsin inhibitor-treated complex cleared slowly compared with untreated complex independent of which protein was radiolabeled. Significant competition for clearance was demonstrated between alpha(2)-macroglobulin-trypsin and activator complex only when the plasmin(ogen) was the radiolabeled moiety. Large molar excesses of alpha(2)-plasmin inhibitor-plasmin failed to retard the clearance of activator complex. Hepatic binding of streptokinase-plasmin, in liver perfusion experiments, was dependent upon prior incubation with plasma (8-10% uptake compared to a background of approximately 2.5%). Substitution of human alpha(2)-macroglobulin for plasma also resulted in binding when the incubation was performed for 10 min at 37 degrees C (7.5%). Electrophoresis experiments confirmed the transfer of 0.8 mol plasmin/mol alpha(2)-macroglobulin when activator complex was incubated at 37 degrees C with alpha(2)-macroglobulin for 40 min. Streptokinase transfer from activator complex to alpha(2)-macroglobulin was negligible. The in vivo clearance of activator complex is proposed to involve active attack of the complex on the alpha(2)-macroglobulin "bait region," resulting in facilitated plasmin transfer. Dissociated streptokinase is rapidly bound and cleared by sites in the liver.
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PMID:Catabolic pathways for streptokinase, plasmin, and streptokinase activator complex in mice. In vivo reaction of plasminogen activator with alpha 2-macroglobulin. 617 57

This study was performed on patients (n = 18) suffering from strictly defined hyperdynamic septic shock. Plasma factors (C-reactive protein, acid alpha 1-glycoprotein, fibrinogen, fibrinopeptide A, fibrinogen-fibrin split products, factor XIII, antithrombin III, complement factors C3 and C4, inter-alpha-trypsin-inhibitor and alpha 2-macroglobulin) measured during hyperdynamic septic shock were highly abnormal. The activation and consumption of clotting, fibrinolytic and complement factors due to system-specific proteinases (such as thrombokinase or plasminogen activators) seemed to be intensified by the nonspecific proteolytic activity of granulocytic proteinases probably released by the action of endotoxins. Possible therapeutic measures to maintain the endogeneous defence mechanism against enhanced proteolysis during septic shock are discussed.
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PMID:Disturbances of selected plasma proteins in hyperdynamic septic shock. 618 74

Using casein plates as a sensitive assay for proteolytic activity, it was observed that sodium-dodecyl sulfate (SDS) and other anionic detergents induce caseinolysis when mixed with sera and plasma. Caseinolysis was dependent on the presence of plasminogen in the fluids and could be blocked by inhibitors of serine proteases and antibody to plasminogen. Similarly, organic solvents such as isopropanol induced caseinolysis after mixing with plasma, but not normal serum. Isopropanol dissociated complexes of alpha 1-antitrypsin or alpha 2-macroglobulin with trypsin preformed in vitro. As both SDS and organic solvents are widely used in biochemical investigations of biological fluids, attention should be paid to the possible induction of proteolysis.
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PMID:Induction of proteolytic activity in serum by treatment with anionic detergents and organic solvents. 619 11


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