1、Enzyme Commission number（based on thechemical reactionstheycatalyze）：EC3.4.21.5
Formation of two products from a substrate byhydrolysis,Template:Serine endopeptidases,Selective cleavage of Arg-|-Gly bonds in fibrinogen to form fibrin and release fibrinopeptides A and B
3、The thrombin (prothrombin) gene is located on the eleventh chromosome (11p11-q12).
Prothrombin(coagulation factor II) isproteolyticallycleaved to form thrombin in thecoagulation cascade, which ultimately results in the reduction of blood loss. Thrombin in turn acts as a serine protease that converts solublefibrinogeninto insoluble strands offibrin, as well as catalyzing many other coagulation-related reactions.
Thrombin is produced by the enzymatic cleavage of two sites on prothrombin by activated Factor X (Xa). The activity of factor Xa is greatly enhanced by binding to activated Factor V (Va), termed the prothrombinase complex. Prothrombin is produced in the liver and is co-translationally modified in a vitamin K-dependent reaction that converts ten glutamic acids on prothrombin to gamma
carboxyglutamic acid (Gla). In the presence of calcium, the Gla residues promote the binding of prothrombin to phospholipid bilayers. Deficiency of vitamin K or administration of the anticoagulant warfarin inhibits the production of gamma-carboxyglutamic acid residues, slowing the activation of the coagulation cascade.
In the blood coagulation pathway, thrombin acts to convertfactor XIto XIa,VIIIto VIIIa,Vto Va,fibrinogentofibrin, andXIIIto XIIIa.
Factor XIIIais atransglutaminasethat catalyzes the formation of covalent bonds between lysine and glutamine residues in fibrin. The covalent bonds increase the stability of the fibrin clot. Thrombininteractswiththrombomodulin.
As part of its activity in the coagulation cascade, thrombin also promotesplateletactivation and aggregation via activation ofprotease-activated receptorson the cell membrane of the platelet
Thrombin bound to thrombomodulin activatesprotein C, an inhibitor of the coagulation cascade. The activation of protein C is greatly enhanced following the binding of thrombin tothrombomodulin, an integral membraneproteinexpressed byendothelialcells. Activated protein C inactivates factors Va and VIIIa. Binding of activated protein C toprotein Sleads to a modest increase in its activity. Thrombin is also inactivated byantithrombin, aserine protease inhibitor.
The molecular weight of prothrombin is approximately 72,000 Da. The catalytic domain is released from prothrombin fragment 1.2 to create the active enzyme thrombin, which has a molecular weight of 36,000 Da. Structurally, it is a member of the large PA clan of proteases.
There are an estimated 30 people in the world that have been diagnosed with the congenital form of Factor II deficiency,[9] which should not be confused with the prothrombin G20210A mutation, which is also called the factor II mutation. Prothrombin G20210A is congenital.
Prothrombin G20210A is not usually accompanied by other factor mutations (i.e., the most common is factor V Leiden). The gene may be inherited heterozygous (1 pair), or much more rarely, homozygous (2 pairs), and is not related to gender or blood type. Homozygous mutations increase the risk of thrombosis more than heterozygous mutations, but the relative increased risk is not well documented. Other potential risks for thrombosis, such as oral contraceptives may be additive. The previously reported relationship of inflammatory bowel disease (i.e., Crohn's disease or ulcerative colitis) and prothrombin G20210A or factor V Leiden mutation have been contradicted by research.
Prothrombin (coagulation factor II) is proteolytically cleaved to form thrombin in the coagulation cascade, which ultimately results in the reduction of blood loss. Thrombin in turn acts as a serine protease that converts soluble fibrinogen into insoluble strands of fibrin, as well as catalyzing many other coagulation-related reactions.
