An endogenous family of proteins belonging to the serpin superfamily that neutralizes the action of thrombin. Six naturally occurring antithrombins have been identified and are designated by Roman numerals I to VI. Of these, Antithrombin I (see FIBRIN) and ANTITHROMBIN III appear to be of major importance.
A plasma alpha 2 glycoprotein that accounts for the major antithrombin activity of normal plasma and also inhibits several other enzymes. It is a member of the serpin superfamily.
An absence or reduced level of Antithrombin III leading to an increased risk for thrombosis.
Endogenous factors and drugs that directly inhibit the action of THROMBIN, usually by blocking its enzymatic activity. They are distinguished from INDIRECT THROMBIN INHIBITORS, such as HEPARIN, which act by enhancing the inhibitory effects of antithrombins.
A highly acidic mucopolysaccharide formed of equal parts of sulfated D-glucosamine and D-glucuronic acid with sulfaminic bridges. The molecular weight ranges from six to twenty thousand. Heparin occurs in and is obtained from liver, lung, mast cells, etc., of vertebrates. Its function is unknown, but it is used to prevent blood clotting in vivo and vitro, in the form of many different salts.
Activated form of factor X that participates in both the intrinsic and extrinsic pathways of blood coagulation. It catalyzes the conversion of prothrombin to thrombin in conjunction with other cofactors.
An enzyme formed from PROTHROMBIN that converts FIBRINOGEN to FIBRIN.

Intracellular accumulation of antithrombin Morioka (C95R), a novel mutation causing type I antithrombin deficiency. (1/31)

Antithrombin (AT) is a major plasma protease inhibitor with three intramolecular disulfide bonds, and its deficiency is associated with increased venous thrombosis. Recently, we found a novel missense mutation named AT Morioka (C95R), which causes the loss of one of the three disulfide bonds. In this study, we prepared Chinese hamster ovary cells stably overexpressing wild type or mutant AT and examined the intracellular fate of the ATs. In pulse-chase experiments, newly synthesized wild type AT was secreted into the medium with a half-life of approximately 1.5 h. In contrast, most of the mutant type AT was not secreted during the chase period of 9 h and, surprisingly, was not degraded in the cells. The kinetics of the secretion suggests that the mutant was secreted about 50 times more slowly into the medium. Most of the mutant AT in the cells had high mannose type oligosaccharides, suggesting that it was retained in the endoplasmic reticulum (ER). In addition, half of the mutant AT existed in a dimeric form with an intermolecular disulfide bond. On immunoelectron microscopy, the mutant AT was found to have accumulated in variously sized structures surrounded by a single membrane in the cytoplasm. Immunogold particles exhibiting calnexin immunoreactivity were detected on the membranes. Ribosomes were attached to some of the small structures that had accumulated the mutant AT. Further, we prepared Chinese hamster ovary cells stably overexpressing another mutant AT in which two cysteine residues at 21 and 95, responsible for disulfide bond formation, were substituted for arginines. In pulse-chase experiments, the mutant AT (C21C,C95R) was secreted faster than that of AT Morioka (C95R) into the medium. These results suggest that AT Morioka remained for a long time in ER without being degraded and accumulated in newly formed membrane structures derived from the ER. The dimerization of AT Morioka (C95R) through Cys-21 seems to be critical for its intracellular accumulation.  (+info)

Deletion of P1 arginine in a novel antithrombin variant (antithrombin London) abolishes inhibitory activity but enhances heparin affinity and is associated with early onset thrombosis. (2/31)

A novel variant of antithrombin, the major serpin inhibitor of coagulation proteases, has been identified in a patient with early onset thrombosis and abnormal plasma antithrombin activity. Sequencing of the antithrombin genes of the patient revealed that one of the two alleles was abnormal due to an in-frame deletion of the codon for the P1 arginine residue. The abnormal antithrombin was separated from the normal inhibitor by complexing the latter with thrombin followed by heparin-agarose affinity chromatography. The purified variant, antithrombin London, was completely inactive as a thrombin or factor Xa inhibitor even after heparin activation. Surprisingly, the variant bound heparin with a K(D) reflecting an approximately 10-fold greater affinity than the normal inhibitor. Stopped-flow kinetic analysis showed that this was almost entirely due to a more favorable conformational activation of the variant than the normal inhibitor, as reflected by a decreased rate constant for reversal of the activation. Consistent with its higher than normal heparin affinity, the inactive antithrombin variant was a potent competitive antagonist of the heparin-catalyzed reaction of normal antithrombin with thrombin but did not affect the uncatalyzed reaction. These results suggest that deletion of the antithrombin P1 residue partially activates the serpin by inducing strain in the reactive center loop, which destabilizes the native loop-buried state and favors the activated loop-exposed state with high heparin affinity. The unusually severe thrombosis associated with the heterozygous mutation may be explained by the ability of antithrombin London to bind endogenous heparan sulfate or heparin molecules with high affinity and to thereby block activation of the normal inhibitor.  (+info)

P1 variant antithrombins Glasgow (393 Arg to His) and Pescara (393 Arg to Pro) have increased heparin affinity and are resistant to catalytic cleavage by elastase. Implications for the heparin activation mechanism. (3/31)

The heparin affinity of normal and two P1 variants of antithrombin-III (AT) was studied by gradient elution with NaCl in Tris buffer on heparin-Sepharose. At pH 7.4 normal AT eluted at [Na+] 0.78 mol/l and the variants both showed increased affinity with AT Pescara eluting at [Na+] 0.86 mol/l and AT Glasgow at [Na+] 0.92 mol/l. We have earlier proposed a model for heparin activation in which the native state of AT maintains a salt bridge involving the P1 Arg-393 residue. Binding of heparin induces a higher heparin affinity conformation in which the salt bridge is disrupted to reveal the reactive centre for inhibition of thrombin. The Glasgow and Pescara variants, lacking a reactive centre P1 basic residue, would be unable to form this salt bridge, and we suggested that the high affinity conformation which they adopt as their native state would resemble the heparin induced conformation. To examine this model, we measured the heparin induced fluorescence of two P1 variants and tested the susceptibility of their reactive loops to catalytic cleavage. Both variants had fluorescence spectra indistinguishable from normal AT. In the absence of heparin, neither variant was more susceptible than normal to catalytic cleavage by human neutrophil elastase. These findings suggest that the conformation of these P1 variants is different to that of fully heparinized normal AT.  (+info)

Replacement of Phe274 with conserved residue Tyr274 for reactive center loop expulsion in antithrombin. (4/31)

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Use of dabigatran etexilate to reduce breast cancer progression. (5/31)

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Endothelial differentiation of adipose-derived stem cells from elderly patients with cardiovascular disease. (6/31)

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Development of a recombinant antithrombin variant as a potent antidote to fondaparinux and other heparin derivatives. (7/31)

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Intravascular inhibition of factor VIIa and the analogue NN1731 by antithrombin. (8/31)

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Antithrombin proteins are a type of protein found in the blood that inhibit the formation of blood clots. They work by binding to and neutralizing thrombin and other coagulation factors, such as factor Xa, that are involved in the coagulation cascade. Antithrombin proteins are an important part of the body's natural anticoagulant system, which helps to prevent excessive clotting and maintain proper blood flow.

Antithrombin proteins can be increased through the use of medications such as heparin, which binds to and enhances the activity of antithrombin. This is why heparin is often used as a treatment for conditions associated with abnormal blood clotting, such as deep vein thrombosis or pulmonary embolism.

It's worth noting that while antithrombin proteins are important for preventing excessive clotting, having too few of these proteins can also be a problem, as it can increase the risk of abnormal bleeding.

Antithrombin III is a protein that inhibits the formation of blood clots (thrombi) in the body. It does this by inactivating several enzymes involved in coagulation, including thrombin and factor Xa. Antithrombin III is produced naturally by the liver and is also available as a medication for the prevention and treatment of thromboembolic disorders, such as deep vein thrombosis and pulmonary embolism. It works by binding to and neutralizing excess clotting factors in the bloodstream, thereby reducing the risk of clot formation.

Antithrombin III (ATIII) deficiency is a genetic disorder that affects the body's ability to regulate blood clotting. ATIII is a protein produced in the liver that inhibits the activity of thrombin and other coagulation factors, preventing excessive clot formation.

People with ATIII deficiency have lower than normal levels of this protein, which can lead to an increased risk of developing abnormal blood clots (thrombosis) in veins, particularly deep vein thrombosis (DVT) and pulmonary embolism (PE). These clots can cause serious complications, including damage to the affected veins, organ damage, and even death.

ATIII deficiency can be classified into two types: type I and type II. Type I is characterized by a quantitative decrease in ATIII levels, while type II is characterized by a qualitative defect that results in reduced functional activity of the protein.

The condition is usually inherited in an autosomal dominant manner, meaning that a person has a 50% chance of inheriting the gene mutation from an affected parent. However, some cases may occur spontaneously due to new mutations in the ATIII gene. Treatment for ATIII deficiency typically involves anticoagulation therapy with medications such as heparin or warfarin to prevent blood clots from forming.

Antithrombins are substances that prevent the formation or promote the dissolution of blood clots (thrombi). They include:

1. Anticoagulants: These are medications that reduce the ability of the blood to clot. Examples include heparin, warfarin, and direct oral anticoagulants (DOACs) such as apixaban, rivaroxaban, and dabigatran.
2. Thrombolytic agents: These are medications that break down existing blood clots. Examples include alteplase, reteplase, and tenecteplase.
3. Fibrinolytics: These are a type of thrombolytic agent that specifically target fibrin, a protein involved in the formation of blood clots.
4. Natural anticoagulants: These are substances produced by the body to regulate blood clotting. Examples include antithrombin III, protein C, and protein S.

Antithrombins are used in the prevention and treatment of various thromboembolic disorders, such as deep vein thrombosis (DVT), pulmonary embolism (PE), stroke, and myocardial infarction (heart attack). It is important to note that while antithrombins can help prevent or dissolve blood clots, they also increase the risk of bleeding, so their use must be carefully monitored.

Heparin is defined as a highly sulfated glycosaminoglycan (a type of polysaccharide) that is widely present in many tissues, but is most commonly derived from the mucosal tissues of mammalian lungs or intestinal mucosa. It is an anticoagulant that acts as an inhibitor of several enzymes involved in the blood coagulation cascade, primarily by activating antithrombin III which then neutralizes thrombin and other clotting factors.

Heparin is used medically to prevent and treat thromboembolic disorders such as deep vein thrombosis, pulmonary embolism, and certain types of heart attacks. It can also be used during hemodialysis, cardiac bypass surgery, and other medical procedures to prevent the formation of blood clots.

It's important to note that while heparin is a powerful anticoagulant, it does not have any fibrinolytic activity, meaning it cannot dissolve existing blood clots. Instead, it prevents new clots from forming and stops existing clots from growing larger.

Factor Xa is a serine protease that plays a crucial role in the coagulation cascade, which is a series of reactions that lead to the formation of a blood clot. It is one of the activated forms of Factor X, a pro-protein that is converted to Factor Xa through the action of other enzymes in the coagulation cascade.

Factor Xa functions as a key component of the prothrombinase complex, which also includes calcium ions, phospholipids, and activated Factor V (also known as Activated Protein C or APC). This complex is responsible for converting prothrombin to thrombin, which then converts fibrinogen to fibrin, forming a stable clot.

Inhibitors of Factor Xa are used as anticoagulants in the prevention and treatment of thromboembolic disorders such as deep vein thrombosis and pulmonary embolism. These drugs work by selectively inhibiting Factor Xa, thereby preventing the formation of the prothrombinase complex and reducing the risk of clot formation.

Thrombin is a serine protease enzyme that plays a crucial role in the coagulation cascade, which is a complex series of biochemical reactions that leads to the formation of a blood clot (thrombus) to prevent excessive bleeding during an injury. Thrombin is formed from its precursor protein, prothrombin, through a process called activation, which involves cleavage by another enzyme called factor Xa.

Once activated, thrombin converts fibrinogen, a soluble plasma protein, into fibrin, an insoluble protein that forms the structural framework of a blood clot. Thrombin also activates other components of the coagulation cascade, such as factor XIII, which crosslinks and stabilizes the fibrin network, and platelets, which contribute to the formation and growth of the clot.

Thrombin has several regulatory mechanisms that control its activity, including feedback inhibition by antithrombin III, a plasma protein that inactivates thrombin and other serine proteases, and tissue factor pathway inhibitor (TFPI), which inhibits the activation of factor Xa, thereby preventing further thrombin formation.

Overall, thrombin is an essential enzyme in hemostasis, the process that maintains the balance between bleeding and clotting in the body. However, excessive or uncontrolled thrombin activity can lead to pathological conditions such as thrombosis, atherosclerosis, and disseminated intravascular coagulation (DIC).

Compared patterns of antithrombin III, protein C, and protein S deficiencies.. F Fourrier, C Chopin, J Goudemand, S Hendrycx, C ... the comparative prognostic value of initial antithrombin III (ATIII), protein C (PC), and protein S (PS) levels; and (3) the ... Initial and sequential levels of ATIII (activity), PC (antigen and activity), PS (total and free), and C4b binding protein ( ...
Antithrombin III. Antithrombin III is a serum protease inhibitor that inhibits the blood coagulation protease, thrombin, and is ... Scripps Laboratories is a world-leading producer and supplier of purified human Antithrombin III. Products are prepared on-site ... Clinical conditions associated with low levels of Antithrombin III are venous thromboembolism and liver disease. Elevated ...
Thrombin-antithrombin complex (TAT) is a protein complex of thrombin and antithrombin. It is a marker of net activation of ... Since thrombin is rapidly bound by antithrombin, TAT is a useful measure for thrombin level in the blood. Thrombin can pass the ... "Analysis of thrombin-antithrombin complex contents in plasma and hematoma fluid of hypertensive intracerebral hemorrhage ...
Protein C, Protein S, Antithrombin III, and Factor V Leiden Deficiencies. Deficiencies of antithrombin III, protein C, and ... Deficiency of the naturally occurring anticoagulant proteins antithrombin III, protein C, and protein S, in addition to aPC ... Antithrombin III, protein C, and protein S are all essential components of the coagulation process. All are synthesized by the ... The relatively rare defects of antithrombin III, protein C, and protein S deficiencies are found in 15-20% of thrombophilic ...
Protein C or S tests - Note that protein S activity is decreased during pregnancy; if possible, the protein study should be ... Antithrombin III assays. Other studies may be indicated to investigate for SLE, other causes of vasculitis, and other systemic ...
Known thrombogenic mutations (e.g., factor V Leiden; prothrombin mutation; and protein S, protein C, and antithrombin ...
Hereditary antithrombin deficiency is a disorder of blood clotting. Explore symptoms, inheritance, genetics of this condition. ... Antithrombin blocks the activity of proteins that promote blood clotting, especially a protein called thrombin. ... This gene provides instructions for producing a protein called antithrombin (previously known as antithrombin III). This ... Most of the mutations that cause hereditary antithrombin deficiency change single protein building blocks (amino acids) in ...
Nonstandard abbreviations used: APC, activated protein C; aPTT, activated partial thromboplastin time; AT, antithrombin; B6, ... The protein encoded by a growth arrest-specific gene (gas6) is a new member of the vitamin K-dependent proteins related to ... Activated human protein C prevents thrombin-induced thromboembolism in mice. Evidence that activated protein C reduces ... Disruption of the protein C inhibitor gene results in impaired spermatogenesis and male infertility. J. Clin. Invest. 106:1531- ...
Congenital antithrombin III deficiency is a genetic disorder that causes the blood to clot more than normal. ... Congenital antithrombin III deficiency is a genetic disorder that causes the blood to clot more than normal. ... The abnormal gene leads to a low level of the antithrombin III protein. This low level of antithrombin III can cause abnormal ... Antithrombin III is a protein in the blood that blocks abnormal blood clots from forming. It helps the body keep a healthy ...
Protein C or S tests - Note that protein S activity is decreased during pregnancy; if possible, the protein study should be ... Antithrombin III assays. Other studies may be indicated to investigate for SLE, other causes of vasculitis, and other systemic ...
Thrombin-Antithrombin Complex) CLIA Kit from Gentaur Clia Kits. Cat Number: G-EC-01663. USA, UK & Europe Distribution. ... SARS-CoV-2 Spike Protein S1 RBD ELISA Kit , G-EC-02191 ... Mouse TAT (Thrombin-Antithrombin Complex) CLIA Kit , G-EC-01663 ... Mouse TAT (Thrombin-Antithrombin Complex) CLIA Kit , G-EC-01663. Rating * Select Rating. 1 star (worst). 2 stars. 3 stars ( ... Mouse TAT (Thrombin-Antithrombin Complex) CLIA Kit , G-EC-01663. Gentaur Clia ...
... antithrombin III [ATIII], protein C, and protein S deficiency); arterial thromboembolic disease (ie, prosthetic heart valves, ...
... is a protein that helps control blood clotting. A blood test can determine the amount of AT III present in your body. ... Antithrombin III (AT III) is a protein that helps control blood clotting. A blood test can determine the amount of AT III ... Antithrombin; AT III; AT 3; Functional antithrombin III; Clotting disorder - AT III; DVT - AT III; Deep vein thrombosis - AT ... Antithrombin III (AT-III) test - diagnostic. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ...
protein S deficiency. *antithrombin III deficiency. *hyperhomocysteinemia. *vasculitis. *age ,65 years. More risk factors ...
Protein C, protein S, or antithrombin deficiency, or other known thrombophilic disorders (4) ... Protein C, protein S, or antithrombin deficiency, or other known thrombophilic disorders ... decreased levels of antifactor Xa and antithrombin III; decreased antithrombin III activity; increased levels of fibrinogen and ... Other binding proteins may be elevated in serum, for example, corticosteroid-binding globulin (CBG), sex hormone-binding ...
Protein C, protein S, or antithrombin deficiency, or other known thrombophilic disorders (4) ... Protein C, protein S, or antithrombin deficiency, or other known thrombophilic disorders ... decreased levels of anti-factor Xa and antithrombin III, decreased antithrombin III activity, increased levels of fibrinogen ... Other binding proteins may be elevated in serum, for example, corticosteroid binding globulin (CBG), sex hormone-binding ...
9] Overexpression of the proliferating cell nuclear antigen gene, the c -MYC oncogene, and the tumor protein p53 gene may also ... Patients usually have high protein concentrations (,2 g/dL); this may not be present in persons with the acute form of the ...
Protein C. Congenital coagulation disorder. Antithrombin III. Congenital coagulation disorder. C1 Esterase inhibitor ... Illustrative list of the main proteins coming from plasma and examples of conditions in which they are used ... Increase awareness of the current challenges related to plasma derived proteins in the general population, among health ... used to purify and concentrate a large array of human plasma proteins), and they do not agree on many policies related to ...
A comparison between the effects of antithrombin III deficiency and protein C deficiency. J Theor Biol (2008) 253:725-38. doi: ...
Serum antithrombin, von Willebrand factor, fibrinogen, and activated protein C concentrations; prothrombin time (PT); and ... and aPTT and significantly decreased antithrombin concentration. Survivors and nonsurvivors had similar flow cytometry and ...
... to 2024 - published on openPR.com ... Antithrombin Market - Size, Share, Outlook, 2026 Antithrombin is a protein present in blood that inhibits blood clotting by ... Antithrombin Market Analysis 2026 Antithrombin is a protein present in blood that inhibits blood clotting by inactivating ... Antithrombin Market analysis 2026 Antithrombin is a protein present in blood that inhibits blood clotting by inactivating ...
The patient also had a protein-losing nephropathy (urine protein:creatinine ratio of 5.5). Antithrombin was likely lost in the ... and serum protein and albumin concentration at the upper end of the reference interval (total protein 7.31 g/dL, reference ... protein-losing nephropathy, protein-losing enteropathy, gastric dilatation/volvulus, and trauma [1-8]. In contrast to feline ... Urine protein to creatinine ratio was 5.5.. On evaluation of a coagulation panel, the dog was thrombocytopenic (146 × 103/μL; ...
Protein C. *Protein S. *Anti-thrombin III. *Lupus Anticoagulant.. We have modernized our flow cytometry with quality reports on ...
... proteins, carbohydrates, lipids proteins, vaccines and herbal medicinal products are exempted because they are unlikely to ... The use of amino acids, proteins and peptides is not expected to have any environmental impact. ... Fass environmental information for Atenativ (antithrombin III, human) from Octapharma (downloaded 2019-09-03). ...
Best early markers of aflatoxicosis were low plasma activities of anticoagulant proteins (protein C, antithrombin) and ... Hypocholesterolemia and decreased plasma protein C and antithrombin activities may function as exposure biomarkers. ...
A novel auto-inhibitory mechanism regulates the functional activity of the cellular prion protein, PrPC, providing for the ... 1998) Antithrombin: its physiological importance and role in DIC Seminars in Thrombosis and Hemostasis 24:19-25. ... 2007) Cellular prion protein regulates beta-secretase cleavage of the alzheimers amyloid precursor protein PNAS 104:11062- ... and propose either a TAT peptide like mechanism or via protein-protein interactions. The propose that these currents, which are ...
It included Factor V Leiden, protein C and S levels, prothrombin mutation, antithrombin deficiency, antiphospholipid antibodies ... iv) Protein C and S deficiency secondary to vitamin K malabsorption [39] ... L. Kallel, S. Matri, S. Karoui, M. Fekih, J. Boubaker, and A. Filali, "Deep venous thrombosis related to protein s deficiency ... one case was associated with protein S deficiency; and in two cases [19, 22] similar to our case there were no other ...
Interaction of human alpha-thrombin and gamma-thrombin with antithrombin III, protein C and thrombomodulin. Eur J Biochem 1985 ... a protein co-factor and membranes containing anionic phospholipids (1). Tissue factor (TF) is a 47-kDa membrane-bound protein ... In fact, the presence of TF in melanoma cell lines has been well documented and the levels of protein expression seem to be ... Several studies have indicated that coagulation proteins play significant roles in cancer biology. Studies employing cultured ...

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