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:3.4.21.7 (plasmin)
9,023 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A 25-year-old man, born in Okinawa, Japan, had a haemorrhagic diathesis characterised by prolonged bleeding and ecchymoses after minor trauma and spontaneous joint haemorrhage. The frequency and severity of these episodes were reduced by an antiplasminic drug. Routine coagulation studies revealed no abnormalities except for significantly sshortened euglobulin-lysis time and whole-blood clot lysis time. Activities of all known clotting and fibrinolytic factors were within normal ranges but no circulating alpha2-plasmin inhibitor was found in the plasma. alpha2-plasmin inhibitor is a potent and fast-acting protease inhibitor. Studies of family members indicated that this abnormality was inherited as an autosomal and recessive gene.
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PMID:Alpha2-plasmin-inhibitor deficiency (Miyasato disease). 8 39

In this paper we describe new and so far unknown protease inhibitors present in the tentacles of the annelid Sabellastarte indica Savingny. At least five different isoinhibitors with inhibitory activity towards trypsin, plasmin, chymotrypsin and kallikrein can be separated electrophoretically. Our protease inhibitor active material differs from the other well known protease inhibitors found in invertebrates in its high molecular weight, in that it is heat-labile and in the occurrence of the isoelectric point in the weakly acid region. On the other hand, the new protease inhibitors have some similarities to the soybean inhibitor described by Kunitz, and to ovomucoid. We also discuss the possibility that these inhibitors may influence the fibrinolytic system.
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PMID:[New protease-inhibitors with broad specificity in the polychaet Sabellastarte indica (Savingny), I (author's transl)]. 12 15

Aprotinin, a protease inhibitor, has been used in a wide variety of pathophysiological states thought to be associated with an increase in protease activity. Opinion differ with respect to the success of the therapy. This paper proposes a rationale for the therapeutic action of aprotinin based on biochemical and physiological evidence. In the kallikrein-kinin system, in addition to kallikrein, other serine-esterases such as trypsin, plasmin, etc. can generate kinin production. In certain disease states such as pancreatitis there is not only an increase in serine-protease activity but frequently these enzymes reach parts of the organism where they are not found in health. Thus in such circumstances increased production of kinins can result. The consequences of increased kinin generation are discussed in light of work indicating their role in metabolic and circulatory homeostasis. Aprotinin is specifically a serine-esterase inhibitor. It is suggested that perhaps the most important action of this compound is as an inhibitor of the kallikrein-kinin system. On this basis a therapeutic regime in various disease states for the use of aprotinin, which allows for control of kinin generation, is suggested.
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PMID:A rationale for the therapeutic action of aprotinin. 15 36

We have examined the ability of 5 tumour cell types to attach to plastic flasks in medium containing either 10% foetal calf serum or 10% normal human serum and compared this ability with cell-associated caseinolytic activity. The cell types used included fibrosarcoma cells which were obtained from a methylcholanthrene-induced tumour in a C57 BL/6 mouse, the SV40-transformed 3T3 (BALB/c) cells, the Walker carcinosarcoma cells and 2 lines of HeLa cells. All 5 cell types attached to the flasks and spread out efficiently in medium containing 10% foetal calf serum. The walker carcinosarcoma cells and the 2 lines of HeLa cells also attached efficiently in medium containing 10% normal human serum and grew into monolayers in this medium. These 3 cell types had no detectable caseinolytic activity. The fibrosarcoma cells and the SV40-transformed 3T3 (BALB/c) cells did not attach in normal human serum-containing medium. These 2 cell types had readily detected caseinolytic activity. Normal human serum and foetal calf serum were compared for levels of protease-inhibitor activity. Human serum was found to have less activity than foetal calf serum against both trypsin and plasmin as well as the cell-associated caseinolytic activity. The low level of protease inhibitor activity in normal human serum may contribute to the inability of this serum to support the attachment of cells with detectable protease activity because the addition of protease inhibitors such as soybean trypsin inhibitor, lima bean trypsin inhibitor and bovine pancreas trypsin inhibitor to normal human serum dramatically enhanced cell attachment. In contrast to this, the addition of E-amino-n-caproic acid to normal human serum and the removal of plasminogen from normal human serum did not enhance its capacity to support cell attachment.
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PMID:Comparison of cell attachment and caseinolytic activities of five tumour cell types. 74 34

To achieve more physiologically successful cardiopulmonary bypass (CPB), the effects of a new synthetic protease inhibitor, nafamostat mesilate (FUT), were examined in open heart surgery. Thirty adult patients were divided into two groups. In Group F (GpF; n = 15), 2 mg/kg/hr of FUT was administered continuously during CPB and 0.2 mg/kg/hr before and after CPB. FUT was not given to Group C patients (GpC; n = 15), who acted as controls. Serotonin and histamine levels in plasma, platelet counts, platelet adhesive function levels, and alpha 2 plasmin inhibitor-plasmin complexes (PIC) were serially measured. The serotonin level in GpF was significantly lower at 5 min of CPB than in GpC. Histamine levels in GpC decreased remarkably after starting CPB, then later recovered; by contrast, they did not decrease in GpF during CPB. At 1 hr after CPB, platelet counts were higher (p < 0.01) in GpF (54 +/- 8%) than in GpC (41 +/- 10%), and platelet adhesion was lower (p < 0.01) in GpF (7 +/- 7%) than in GpC (34 +/- 13%). The PIC was significantly less in GpF than in GpC throughout the surgery. Blood loss in GpF was significantly reduced compared with that in GpC. In conclusion, FUT attenuated chemical mediator reactions, such as plasma serotonin and histamine, and also reduced blood loss by preserving platelets and inhibiting fibrinolysis during CPB.
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PMID:Clinical evaluation of a new synthetic protease inhibitor in open heart surgery. Effect on plasma serotonin and histamine release and blood conservation. 128 Oct 15

The influence of unfractionated heparin [average molecular weight (MW) 10,000-15,000 kD] and low-molecular-weight heparin (average MW 400-600 kD) on the plasma kallikrein-kinin and the fibrinolytic system was studied in vitro. Unfractionated heparin added to plasma gave an increase in kallikrein-like activity with a corresponding decrease of prekallikrein and functional kallikrein inhibition values. Plasmin-like activity was also increased, but minor changes in plasminogen and no change in antiplasmin values occurred. The changes were less pronounced with low molecular heparin compared with unfractionated heparin. The proteolytic changes were reversed by protamine sulfate but not influenced by the protease inhibitor aprotinin. Gel filtration yielded proteolytic activities able to split the plasma kallikrein substrate S-2305 and, to a minor degree, the plasmin substrate S-2251. The proteolytic activities were not due to complex formation with alpha 2-macroglobulin. We speculate that heparin binds to prekallikrein to form a heparin-prekallikrein complex which undergoes conformational changes and displays a kallikrein-like activity with the ability to split small synthetic substrates. Whether it is capable to split natural substrates remains unresolved.
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PMID:Effects of heparin on proteolytic activities in human plasma. 137 15

Aprotinin has been shown to reduce blood loss and blood requirement when administered prior to surgery and this therapeutic benefit appears to be related to its specificity as a protease inhibitor. The inhibition of plasmin by aprotinin is well characterized, but little is known of its effect on thrombin. In preliminary experiments, we showed that aprotinin can prevent platelet aggregation induced by thrombin. Follow-up studies have now been performed in order to clarify the effect of aprotinin on thrombin. A fluorescence study of the direct binding of aprotinin to human alpha-thrombin was analysed according to the Michaelis-Menten model and a dissociation constant of 30 x 10(-6) mol.l-1 was determined. Aprotinin can displace p-aminobenzamidine, a fluorescent-probe molecule which binds to the active site of serine proteases, showing that the active site of thrombin was involved. Aprotinin also inhibited the ability of thrombin to induce a fibrin clot from purified fibrinogen and to induce the hydrolysis of the chromogenic substrate H-D-phenylalanylpipecolylarginine-p-nitroanalidehydrochloride++ + (S-2238). With S-2238, double-reciprocal plots show that the inhibition is competitive with a Ki of 61 microM and a Km of 1.72 microM. Aprotinin was a potent inhibitor of thrombin-induced aggregation. A Schild plot of the aggregation data yielded a slope of 0.97 +/- 0.12 and an apparent dissociation constant of 57.0 +/- 13.1 microM (mean +/- SEM). Thus, the inhibition of thrombin-induced platelet aggregation by aprotinin fits a model of competitive inhibition. Conclusions are that, in addition to a possible direct effect of aprotinin on platelets, the inhibition of thrombin-induced platelet activation by aprotinin can be also explained, in part, by a direct effect of the inhibitor on the thrombin molecule itself. This supports the concept that a proteolytic step is involved in the platelet response to thrombin. Finally, evidence is in favour of the participation of Trp245 in the fluorescence response of thrombin on binding to aprotinin.
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PMID:Aprotinin can inhibit the proteolytic activity of thrombin. A fluorescence and an enzymatic study. 137 6

TGF-beta plays a pivotal role in the pathological accumulation of extracellular matrix in experimental glomerulonephritis. Increased TGF-beta expression leads to increased synthesis and deposition of extracellular matrix components while administration of anti-serum to TGF-beta suppresses the major manifestations of the disease. We hypothesized that TGF-beta might also enhance matrix accumulation by decreasing matrix turnover via effects on protease/protease inhibitor balance. Plasmin is a potent protease capable of degrading a variety of matrix molecules. Plasmin generation from plasminogen is regulated by plasminogen activator(s) (PA) and plasminogen activator inhibitor(s) (PAI). In this study PA activity was markedly reduced and PAI-1 synthesis dramatically increased when TGF-beta was added to normal glomeruli. Diseased glomeruli also showed decreased PA activity, increased PAI-1 synthesis and increased PAI-1 deposition into matrix. Administration of anti-TGF-beta serum to glomerulonephritic rats blocked the expected increase in glomerular PAI-1 deposition. Thus changes in the PA/PAI balance favoring accumulation of matrix are induced by TGF-beta in normal glomeruli and are present in nephritic glomeruli when endogenous TGF-beta production is high. Our findings implicate the plasmin protease system in tissue repair following acute glomerular injury and suggest another mechanism by which TGF-beta enhances the matrix accumulation characteristic of many glomerular diseases.
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PMID:Glomerular matrix accumulation is linked to inhibition of the plasmin protease system. 147 81

Plasminogen activator inhibitor 1 (PAI-1) is the fast-acting inhibitor of both tissue-type and urokinase-type plasminogen activators (t-PA, u-PA) and is an essential regulatory protein of the fibrinolytic system. In the presence of either the protein vitronectin or the glycosaminoglycan heparin, PAI-1 is also an efficient inhibitor of thrombin. To assess whether these cofactors turn PAI-1 into a general protease inhibitor or whether their influence is restricted to thrombin, the second-order association rate constants between PAI-1 and the human plasma proteases t-PA, u-PA, plasmin, thrombin, Factor Xa (FXa), and Factor XIIa (FXIIa) in the absence and in the presence of either vitronectin or heparin are determined. In addition, the role of the PAI-1 reactive site P3 to P3' residues for the specificity of inhibition was studied by using PAI-1 reactive site mutants. Our results show that: (1) Heparin exclusively increases the rate of inhibition of thrombin by PAI-1, whereas in the presence of heparin the rate of inhibition of the other proteases is not altered; (2) Vitronectin is an obligatory cofactor for the inhibition of thrombin by PAI-1. In addition, vitronectin moderately increases the rate of inhibition by PAI-1 of u-PA and of plasmin, but does not alter the rate of inhibition of t-PA, FXa, or FXIIa; (3) Apart from the important role of the P1 residue, no consensus can be presented on the nature of other residues within the P3 to P3' region with regard to target protease specificity.
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PMID:On the target specificity of plasminogen activator inhibitor 1: the role of heparin, vitronectin, and the reactive site. 171 20

Plasma levels of the plasma protease inhibitor alpha-2-macroglobulin (alpha 2-M) were followed for 7 days in 90 patients subjected to various surgical procedures. Alpha 2-M was found to decrease strictly in parallel with the decrease seen for haemoglobin and albumin levels in all patients. Changes were most pronounced after extensive operations; total hip replacement (n = 7), pulmonary resection (n = 11), extensive colo-rectal resection (n = 15), and less pronounced after 'minor' operations; mastectomy (n = 23) proximal gastric vagotomy (n = 5) and moderate colo-rectal resection (n = 29). Levels were lowest on the second to third postoperative day, whereafter they slowly returned to normal, preoperative levels during the 7-day study period. Functional and quantitative alpha 2-M levels almost paralleled each other throughout the 7 days studied. Chromogenic peptide substrate assays indicated circulating plasmin-alpha 2-M complexes, while no protease-alpha 2-M complexes could be demonstrated using sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) or isoelectric focusing (IEF) analyses. Local accumulation and consumption of proteins within wounded tissues, together with haemodilution, were probably the major factors responsible for the decreased plasma levels seen. It is concluded that the plasma levels of alpha 2-M decrease after major elective surgery strictly in parallel with the decrease seen in haemoglobin and albumin levels, and that circulating plasmin-alpha 2-M complexes are probable. The decrease seems to be graded, that is, proportional to the extent of the operative trauma, similar to the postoperative increase seen in positive acute-phase proteins. Thus, alpha 2-M cannot be used as an internal, unchanged plasma protein standard for other protein changes seen after trauma.
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PMID:Alpha-2-macroglobulin decreases parallel to albumin and haemoglobin after elective surgery. 171


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