Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.21.5 (thrombin)
 33,306 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Estrogen-containing compounds are thrombogenic in man. The extent of thrombosis is dose-related, but a measure of this thrombogenicity is not currently available. Evidence is presented, using an animal model of venous thrombosis, that impaired Xa inhibitory activity (the rate of reaction between Xa and antithrombin III) correlates with the development of thrombosis initiated by thrombin in rabbits receiving an oral contraceptive compound. The responses in the clotting assay and in the extent of thrombosis are dose-related. The hypercoagulable state induced by oral contraceptives can be completely reversed by trace amounts of heparin.
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PMID:The activated factor X-antithrombin III reaction rate: a measure of the increased thrombotic tendency induced by estrogen-containing oral contraceptives in rabbits. 64 Apr 89

A marked deficiency in antithrombin III (AT III) was demonstrated in a 39-year-old man suffering from recurrent thrombo-embolic problems. The patient's father had died following a thrombo-embolic disorder. A certain number of members of the family also showed evidence of a marked decrease in AT III levels. Although it was not possible to study the patient's parents, it would seem reasonable to conclude that the diagnosis was one of hereditary deficiency in AT III. The various aspects of this disorder discovered by Egeberg are reviewed: early onset, in several members of the same family, or recurrent thrombo-embolic problems, accompanied by a decrease in functional activity of one of the principal inhibitors of thrombin (AT III), with autosomal dominant transmission and treatment based upon anti-vitamin K agents.
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PMID:[Hereditary antithrombin III deficiency causing recurrent thrombo-embolic problems (author's transl)]. 66 21

Bovine plasma Factor V and Factor Va, the latter prepared by thrombin or venom activator action on Factor V, are not inactivated by diisopropylfluorophosphate or antithrombin III nor do they form identifiable complexes with either of these reagents. On the basis of these data, it is concluded that bovine Factor V and Factor Va are not serine proteases.
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PMID:Insensitivity of factor V and factor Va to diisopropylfluorophosphate and antithrombin III. 66 83

The affinity (Ka) of human coagulation Factor Xa for thrombin-treated (to stimulate the release reaction) platelets has been determined to be 3 to 4 x 10(10) M-1 by equilibrium binding studies using 125I-labeled Xa. The binding of Factor Xa to platelets results in an increase of 300,000-fold in the apparent enzymatic activity of Xa in the conversion of prothrombin to thrombin. The activity of platelet surface Xa is approximately 15-fold greater than that observed with optimum concentrations of bovine Factor V and phospholipids in place of platelets. Ca2+ is required for the Xa-platelet interaction; the optimum concentration is 2.5 mM. Related coagulation factors, including Factor X, Factor IXa, diisopropylphosphoryl Factor Xa, and prothrombin do not complete with Factor Xa for the Xa binding sites. The rate of thrombim formation at saturating amounts of Xa is directly proportional to the number of platelets from 1 x 10(7) to 5 x 10(8) platelets/ml. Factor Xa bound to platelets is not inactivated by antithrombin III. An antibody that inhibits both human and bovine coagulation Factor V activity blocks both Xa binding to released platelets and the rapid thrombin formation associated with this binding, suggesting that Factor V from platelets is involved in the Xa-platelet interaction.
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PMID:Properties of the factor Xa binding site on human platelets. 69 Jan 32

The three cases reported, two mesenteric venous infarctions and one asymptomatic carrier, prove the responsibility of the anti-thrombin III deficiency in the development of apparently primary entero-mesenteric venous infarctions. Thus such a deficiency should be sought routibs. Furthermore, these 3 cases confirm the usual characteristics of the 10 familial cases collected since the princeps description of Egeberg: recurrent thromboembolic disease in the young subject involving essentially the lower limbs, relative resistance to heparin, family history of thromboembolic disease confirming the hereditary nature of the disease with dominant transmission, laboratory confirmation of the quantitative deficiency in antithrombin III, the levels and activity of which are reduced by half, and decrease in laboratory sensitivity to heparin contrasting with normal clotting studies. The family history reveals associated conditions within the syndrome: asthma and Biermer's anemia as well as similarities in leucocyte HLA groups.
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PMID:[Recurrent familial thromboembolic disease due to congenital deficiency in anti-thrombin III. Preliminary study of 3 cases (author's transl)]. 73 87

The complexes formed by antithrombin III with activated bovine Factor X and thrombin have been studied by gel electrophoresis in dodecyl sulfate. When subjected to electrophoresis at pH 7, the complexes remain intact, whereas electrophoresis at pH 9 in the presence of Tris results in their dissociation. Dissociation of both the Factor Xa-antithrombin III complex and the thrombin-antithrombin III complex in dodecyl sulfate produces a modified form of antithrombin III which, unlike the native inhibitor, apparently consists of two chains. Gel electrophoresis of the dissociated complexes has also been used to study the sites where the complexes are cleaved by the respective enzymes. The cleavage of the Factor Xa-inhibitor complex by Factor Xa apparently results from hydrolysis of a single bond in the enzyme part of the complex and releases a 15,000-dalton NH2-terminal fragment of the heavy chain, with the light chain attached. Cleavage of the thrombin-inhibitor complex by thrombin involves several cleavages of the heavy (B) chain of the thrombin part of that complex. Neither enzyme-inhibitor complex is subject to cleavage by free enzyme in the inhibitor part of the complex under the conditions used.
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PMID:Dissociation of complexes and their derivatives formed during inhibition of bovine thrombin and activated factor X by antithrombin III. 76 13

A simple amidolytic method for the determination of the concentration of functionally active antithrombin III is described. Plasma is diluted with buffer containing EDTA and Polybrene. In stage I, diluted plasma is incubated with thrombin. EDTA retards fibrin polymerization, and plasma fibrinogen does not influence the assay. Polybrene makes the assay result independent of heparin. In stage II, remaining thrombin is determined with the chromogenic substrate benzoyl-Phe-Arg-p-NA. The method is simpler and has a higher accuracy than clotting methods. There is a close correlation between the results obtained with this assay and with immunoassay of antithrombin III.
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PMID:A simple amidolytic method for the determination of functional active antithrombin III. 81 98

Factor VIII is present in plasma in a precursor or inactive form. When bovine factor VIII that has been purified approximately 10,000-fold is incubated with thrombin, an activated product is formed which participates in the conversion of factor X to factor Xa in the presence of factor IXa, calcium ions, and phospholipid. This activated product, which has been tentatively identified as activated factor XIII, was stable when formed in the presence of 0.25M CaCl2 but was rapidly inactivated in the absence of CaCl2. It was inhibited by diisopropyl phosphorofluoridate and antithrombin III, suggesting that it is a serine enzyme. The exact role of this serine enzyme in the intrinsic pathway of coagulation remains to be established.
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PMID:Formation of a serine enzyme in the presence of bovine factor VIII (antihemophilic factor) and thrombin. 87 60

Possible increased activation of the coagulation pathway was measured in a group of patients with neoplastic diseases. In addition to standard tests, the thromboplastin generation test, thrombin generation test and immunologic and coagulant activities of both Factor VIII and antithrombin III were utilized in the evaluation. The correlation between immuno-Factor VIII (VIII-Ag) and its clotting activity (VIII-C1) was good (r = 0.83). In contrast, this was not the situation for antithrombin III-Ag and its clotting activity. Thromboplastin generation was accelerated in 60% and thrombin generation was accelerated in 40% of the patients. Fibrinogen was elevated in half the cases: in most of these patients, thrombin times were slightly prolonged. These results indicate that some patients who have cancer have abnormal clotting patterns and are often in a potentially hypercoagulable state that is reflected by the thromboplastin generation test, thrombin generation test, and high levels of Factor VIII (both VIII-Ag and VIII-C1).
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PMID:Antithrombin III and Factor VIII in patients with neoplasms. 87

Following clotting factor assays were performed on the fluid of burn blisters of 11 patients with severe burns: Fibrinogen levels, Factor II, V, X and XIII, thrombin time, fibrin split products, plasminogen, antithrombin III, IgA, IgM, IgG, ethanol gelation test and total proteins. The results showed, that a quantity of Factor II, X and XIII, antithrombin III, plasminogen and IgG had left the circulation. On the contrary we found only small concentrations of Factor V, fibrinogen, IgM and IgA in the fluid of burn blisters. This distribution suggested that the losses of plasma proteins into the burn blisters were correlated to their concentration and their molecular weight. The decrease of plasma coagulation proteins during the first days after severe burns was probably partly due to losses through the walls of the vessels, because of the increased capillary permeability.
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PMID:[Coagulation factors in human born blisters (author's transl)]. 91 8


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