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Thrombin enzyme (Activated Factor IIa) is an important clotting promoter that controls the transformation of soluble fibrinogen to insoluble active fibrin strands. Thrombin is a coagulation protein and a serine protease (EC 3.4.21.5) that catalyzes many coagulation-related reactions. Thrombin triggers factor-XI, factor-V, Factor-XIII and factor-VIII. Thrombin endorses platelet activation, using activation of protease-activated receptors on the platelet. As a result of its high proteolytic specificity, thrombin has become an important biochemical protein. The thrombin cleavage site (Leu-Val-Pro-Arg-Gly-Ser) is widely used in linker regions of recombinant fusion protein constructs. After the purification of the fusion protein, thrombin is used to cleave between the Arginine and Glycine residues of the cleavage site, efficiently removing the purification tag from the protein of interest with a high degree of specificity.

Coagulation factor II (F2) is proteolytically cleaved to form thrombin in the 1st step of the coagulation cascade which ultimately results in the stemming of blood loss. F2 also has a role in preserving vascular integrity during development and postnatal life. F2 gene mutations lead to various forms of thrombosis and dysprothrombinemia.

Thrombin enzyme (Activated Factor IIa) is an important clotting promoter that controls the transformation of soluble fibrinogen to insoluble active fibrin strands. Thrombin is a coagulation protein and a serine protease (EC 3.4.21.5) that catalyzes many coagulation-related reactions. Thrombin triggers factor-XI, factor-V, Factor-XIII and factor-VIII. Thrombin endorses platelet activation, using activation of protease-activated receptors on the platelet. As a result of its high proteolytic specificity, thrombin has become an important biochemical protein. The thrombin cleavage site (Leu-Val-Pro-Arg-Gly-Ser) is widely used in linker regions of recombinant fusion protein constructs. After the purification of the fusion protein, thrombin is used to cleave between the Arginine and Glycine residues of the cleavage site, efficiently removing the purification tag from the protein of interest with a high degree of specificity.

Thrombin enzyme (Activated Factor IIa) is an important clotting promoter that controls the transformation of soluble fibrinogen to insoluble active fibrin strands. Thrombin is a coagulation protein and a serine protease (EC 3.4.21.5) that catalyzes many coagulation-related reactions. Thrombin triggers factor-XI, factor-V, Factor-XIII and factor-VIII. Thrombin endorses platelet activation, using activation of protease-activated receptors on the platelet. As a result of its high proteolytic specificity, thrombin has become an important biochemical protein. The thrombin cleavage site (Leu-Val-Pro-Arg-Gly-Ser) is widely used in linker regions of recombinant fusion protein constructs. After the purification of the fusion protein, thrombin is used to cleave between the Arginine and Glycine residues of the cleavage site, efficiently removing the purification tag from the protein of interest with a high degree of specificity.

Thrombin enzyme (Activated Factor IIa) is an important clotting promoter that controls the transformation of soluble fibrinogen to insoluble active fibrin strands. Thrombin is a coagulation protein and a serine protease (EC 3.4.21.5) that catalyzes many coagulation-related reactions. Thrombin triggers factor-XI, factor-V, Factor-XIII and factor-VIII. Thrombin endorses platelet activation, using activation of protease-activated receptors on the platelet. As a result of its high proteolytic specificity, thrombin has become an important biochemical protein. The thrombin cleavage site (Leu-Val-Pro-Arg-Gly-Ser) is widely used in linker regions of recombinant fusion protein constructs. After the purification of the fusion protein, thrombin is used to cleave between the Arginine and Glycine residues of the cleavage site, efficiently removing the purification tag from the protein of interest with a high degree of specificity.

Thrombomodulin, also referred to THBD, is an endothelial cell-expressed, transmembrane glycoprotein that can form a complex with the coagulation factor, thrombin. This complex increasethe activation of protein C in the anticoagulant pathway by forming a 1:1 stoichiometric complex with thrombin. Thrombomodulinbound thrombin has procoagulant effect at the same time by inhibiting fibrinolysis by cleaving thrombinactivatable fibrinolysis inhibitor (TAFI) into its active form. Reduced levels of thrombomodulin or increased serum levels of THBD can correlate with pathogenesis of certain cardiovascular diseases, such as atherosclerosis and thrombosis. Furthermore, it associated with, diabetes mellitus, liver cirrhosis, cerebral & myocardial infarction, and multiple sclerosis.

Prothrombin produced in the liver is a vitamin K-dependent plasma protein. Before prothrombin is secreted into the plasma it goes through post translational modification by vitamin K-dependent carboxylase. The vitamin K-dependent carboxylase convertsprothrombin to 10 glutamic acid residues to gamma carboxyglutamic acid. Prothrombin comprises of 2 kringle regions which are found among residues a.a. 40 & 270 of the mature plasma protein and substitute the growth factor domains located in numerous plasma serine proteases.

Batroxobin is a serin protease that reduces fibronogen levels and is originally extracted from snake venom of Bothrops Atrox. Batroxobin is used in defibrinogenation and thrombolysis and also has an effect on c-fos gene and growth factor.
Batroxobin can efficiently restrain proliferation of VSMCs, by blocking the release and uptake of Ca2+, thus influencing [Ca2+]i.
Batroxobin converts fibrinogen to fibrin through the restricted release of fibrinopeptide-A from fibrinogen to promote blood to clot. Unlike thrombin, it is not affected by heparin and hirudin.

Tissue factor is well-known as the main cellular initiator of blood coagulation. The Tissue factor gene encodes coagulation factor III which is a cell surface glycoprotein that enables cells to initiate the blood coagulation cascades, and functions as the high-affinity receptor for the coagulation factor VII. Following vessel injury, the Tissue Factor and Factor VIIa complex activates the coagulation protease cascade, which leads to fibrin deposition and activation of platelets. The ensuing complex presents a catalytic event, which is responsible for initiation of the coagulation protease cascades by specific limited proteolysis. Therefore, Tissue factor has a role in normal hemostasis by initiating the cell-surface assembly and propagation of the coagulation protease cascade. Tissue Factor can also be stimulated by the inflammatory mediators interleukin 1 and TNF, as well as by endotoxin, to appear on monocytes and vascular endothelial cells as a component of cellular immune response.
Tissue factor is the only one in the coagulation pathway for which a congenital deficiency has not been described. Certain levels of Tissue Factor are essential for the maintained viability and growth of endothelium and Tissue Factor-expressing tumor cells. Additionally, abnormal Tissue Factor expression inside the vasculature initiates life threatening thrombosis in various diseases, for example sepsis, atherosclerosis, and cancer. Alternative spliced Tissue Factor expression advances tumor growth, and is linked to increased tumor cell proliferation and angiogenesis in pancreatic cancer.

Coagulation factor VII is a vitamin K-dependent factor which is essential for hemostasis. It circulates in the blood as a zymogen which is later converted to an active form by factor IXa, factor Xa, factor XIIa, or thrombin by minor proteolysis. Upon activation of factor VII, a heavy chain with a catalytic domain and a light chain with 2 EGF-like domains are generated, and the two chains are held together by a disulfide bond. The presence of factor III and calcium ions further activates the coagulation cascade by converting factor IX to factor IXa and/or factor X to factor Xa. Alternative splicing of factor VII results in 2 transcripts. Defects in coagulation factor VII can cause coagulopathy. Coagulation factor VII initiates the extrinsic pathway of blood coagulation. Minor proteolysis converts factor VII to factor VIIa by factors Xa, XIIa, IXa, or thrombin. Factor VIIa also converts factor IX to factor IXa in the presence of tissue factor and calcium.

Thrombopoietin is a glycoprotein hormone produced mainly by the liver and the kidney which regulates the production of platelets by the bone marrow. TPO stimulates the production as well as differentiation of megakaryocytes, the bone marrow cells which fragment into large numbers of platelets.

Prothrombin Complex Concentrate (PCC) is a combination of several blood clotting factors II, VII, IX and X. PCC is used in the treatment of the congenital bleeding disorders associated with Factors II, VII, IX, and X deficiencies. PCC reverses the effect of warfarin (a coumarin anti-coagulant) and is used in cases of significant bleeding in patients with a coagulopathy, for example, gastrointestinal haemorrhage or intracranial haemorrhage. The PCC is also extensively used in treating acquired coagulation abnormalities secondary to vitamin K deficiency, warfarin ingestion, and various types of liver disease.
Hepatitis, anaphylaxis and thrombosis have been reported as complications of prothrombin complex concentrates administration.

Human Factor IX also called Christmas-Factor is a glycoprotein, which is synthesized in the liver and belongs to the serine proteases system and is part of the S1 peptidase family.
Lack of Factor-IX causes Hemophilia-B meaning Christmas Disease. Factor-IX has a N-terminus region which contains 12xGla residues which asist the calcium dpendant binding of Factor-IX to the phospholipid surface. Factor-IX is activated by either factor XIa or the factor VIIa/tissue factor/phospholipid complex. Cleavage yields the intermediate IXa, which is subsequently converted to the fully active form IXab.
Factor-IX binds initially to exosites on the factor XIa heavy chain, followed by interaction at the active site with subsequent bond cleavage. Coagulation factor IX is activated by interaction with the erythrocyte membrane, causing intrinsic coagulation. Chaperones & lectins act simultaniously to guarantee the proper folding of Factor-IX and the retention of mutant molecules. Human Factor IX, activated by either the Contact or Tissue Factor Pathway, is responsible for the activation of Factor X to Xa.

Tissue factor is well-known as the main cellular initiator of blood coagulation. The Tissue factor gene encodes coagulation factor III which is a cell surface glycoprotein that enables cells to initiate the blood coagulation cascades, and functions as the high-affinity receptor for the coagulation factor VII. Following vessel injury, the Tissue Factor and Factor VIIa complex activates the coagulation protease cascade, which leads to fibrin deposition and activation of platelets. The ensuing complex presents a catalytic event, which is responsible for initiation of the coagulation protease cascades by specific limited proteolysis. Therefore, Tissue factor has a role in normal hemostasis by initiating the cell-surface assembly and propagation of the coagulation protease cascade. Tissue Factor can also be stimulated by the inflammatory mediators interleukin 1 and TNF, as well as by endotoxin, to appear on monocytes and vascular endothelial cells as a component of cellular immune response.
Tissue factor is the only one in the coagulation pathway for which a congenital deficiency has not been described. Certain levels of Tissue Factor are essential for the maintained viability and growth of endothelium and Tissue Factor-expressing tumor cells. Additionally, abnormal Tissue Factor expression inside the vasculature initiates life threatening thrombosis in various diseases, for example sepsis, atherosclerosis, and cancer. Alternative spliced Tissue Factor expression advances tumor growth, and is linked to increased tumor cell proliferation and angiogenesis in pancreatic cancer.

Thrombospondin-1 (TSP1) is a member of the Thrombospondin family and is encoded by the gene THBS1 which is a subunit of a disulfide-linked homotrimeric protein. Thrombospondin-1 is an adhesive glycoprotein that mediates cell-to-cell and cell-to-matrix interactions. Thrombospondin-1 can bind to fibrinogen, fibronectin, laminin, type V collagen and integrins alpha-V/beta-1. TSP1 has been shown to play roles in platelet aggregation, angiogenesis, and tumorigenesis. TSP1 has been shown to be a natural inhibitor of neovascularization and tumorigenesis in healthy tissue. TSP1 interacts with no less than 12 cell adhesion receptors, including CD36, av integrins, b1 integrins, syndecan, and integrin-associated protein (IAP or CD47). It also interacts with various proteases involved in angiogenesis, including plasminogen, matrix metalloproteinase, thrombin, cathepsin, and elastase. Positive and negative modulation of endothelial cell adhesion, motility, and growth are attributed to TSP1. Recently, thrombospondin-1 was found to bind to the reelin receptors, ApoER2 and VLDLR, in so doing affecting neuronal migration in the rostral migratory stream.

TFPI is a protease inhibitor which controls the tissue factor (TF)-dependent pathway of blood coagulation. The coagulation process starts with the creation of a factor VIIa-TF complex, that proteolytically triggers additional proteases (factors IX and X) and eventually results in a fibrin clot. TFPI inhibits the activated factor X and VIIa-TF proteases in an autoregulatory loop. TFPI is glycosylated and predominantly located in the vascular endothelium and plasma in both free forms and complexed with plasma lipoproteins. A number of alternatively spliced transcript variants of this gene have are known, however the full-length nature of several of these variants were not yet established.

Bivalirudin directly inhibits thrombin by specifically binding as well to the catalytic site and to the anion-binding exosite of circulating and clot-bound thrombin. Bivalirudin is a specific and reversible direct thrombin inhibitor.
Thrombin, which is a serine protease, plays a central role in the thrombotic process; it cleaves fibrinogen into fibrin monomers and activates Factor XIII to Factor XIIIa, allowing fibrin to develop a covalently cross-linked structure which stabilizes the thrombus. Thrombin also activates Factors V and VIII, which promotes further thrombin generation, activates platelets, stimulating aggregation and granule release.

Thrombopoietin is a glycoprotein hormone produced mainly by the liver and the kidney that regulates the production of platelets by the bone marrow. It stimulates the production and differentiation of megakaryocytes, the bone marrow cells that fragment into large numbers of platelets.

Recombinant Hirudin is a potent thrombin inhibitor originally derived from the medicinal leech. Hirudin acts directly on thrombin rather than through other clotting factors. The mechanism of Hirudin-thrombin appears to be unique. The conversion of fibrinogen into fibrin by the serine protease enzyme thrombin is a major event in the final stages of blood coagulation. In the final stages of coagulation prothrombinase converts prothrombin into thrombin. Fibrin is subsequently cross linked by factor XIII to form a blood clot. The primary inhibitor of thrombin in normal blood circulation is antithrombin III. The anticoagulatant activity of hirudin is derived from its ability to inhibit the pro-coagulant activity of thrombin (similar to antithrombin III activity). Hirudin is the strongest natural inhibitor of thrombin. Hirudin binds to and inhibits only the activity of thrombin forms with a specific activity on fibrinogen contrasting to antithrombin III activity. Therefore, hirudin has a thrombolytic activity since it prevents or dissolves the formation of clots and thrombi. Hirudin also has therapeutic significance in blood coagulation disorders, in the treatment of skin hematomas and of superficial varicose veins. Hirudin does not hinder with the biological activity of other serum proteins and can also act on complexed thrombin, thus having an advantage over more common anticoagulants and thrombolytics. It is complicated to extract large quantities of hirudin from natural sources; therefore a method for producing and purifying hirudin using recombinant biotechnology has been developed.

TFPI2 takes part in the regulation of plasmin-mediated matrix remodeling. Inhibits trypsin, plasmin, factor VIIa/tissue factor and weakly factor Xa. TFPI2 doesn’t have any influence on thrombin.

Cathepsin D is synthesized as a 54kDa precursor, which is proteolytically processed to an intermediate 48kDa single chain, which matures into more stable 34kDa and 14kDa two chain form. It is an estrogen-regulated lysosomal protease that has been suggested to facilitate cancer cell migration and invasion by digesting the basement membrane, extracellular matrix, and xonnective tissue. Because of its mitogenic and proteolytic activities, it has been implicated as a prognostic marker in many tumor types. Cathepsin D is expressed in epithelial cells as well as in macrophages.

TFPI is a protease inhibitor which controls the tissue factor (TF)-dependent pathway of blood coagulation. The coagulation process starts with the creation of a factor VIIa-TF complex, that proteolytically triggers additional proteases (factors IX and X) and eventually results in a fibrin clot. TFPI inhibits the activated factor X and VIIa-TF proteases in an autoregulatory loop. TFPI is glycosylated and predominantly located in the vascular endothelium and plasma in both free forms and complexed with plasma lipoproteins. A number of alternatively spliced transcript variants of this gene have are known, however the full-length nature of several of these variants were not yet established.

Aprotinin inhibits the activity of several proteolytic enzymes such as chymotrypsin, kallikrein, plasmin and trypsin. Aprotinin is present in blood and in most tissues, with a high concentration in lung. Aprotinin inhibits pro-inflammatory cytokine release and maintains glycoprotein homeostasis. In platelets, aprotinin reduces glycoprotein loss (e.g., GpIb, GpIIb/IIIa), while in granulocytes it prevents the expression of pro-inflammatory adhesive glycoproteins (e.g., CD11b).