Does thrombin activate factor XI?

Thrombin can activate factor XI in the presence of dextran sulfate or sulfatides. However, a physiological cofactor for thrombin activation of factor XI has not been identified.

How is factor XI activated?

Factor XI (FXI) is also a zymogen of the serine protease that is activated by FXII or thrombin, or autocatalytically. It is composed of four so-called apple domains in the heavy chain and a protease domain, and circulates as a homodimer.

Which coagulation factor activates factor XI?

“Activation of human blood coagulation factor XI independent of factor XII. Factor XI is activated by thrombin and factor XIa in the presence of negatively charged surfaces”.

What factors does thrombin activate?

Thrombin is an unique molecule that functions both as a procoagulant and anticoagulant. In its procoagulant role it activates platelets through its receptor on the platelets. It regulates its own generation by activating coagulation factors V, VIII and even XI resulting in a burst of thrombin formation.

Is Va factor a Zymogen?

Introduction. Human coagulation factor X (FX), a vitamin K (VKD)-dependent plasma zymogen, plays a central role in the blood coagulation cascade (Davie et al., 1991). It is synthesized in the liver as a single-chain precursor. In plasma, FX circulates as a two-chain glycoprotein (∼59 KDa).

Is factor Va cofactor for thrombin generation?

This study shows that, out of all the cofactors that were tested, FVa is a phospholipid-dependent cofactor for thrombin-dependent FXI activation, in both a purified system and in plasma.

How common is Factor XI deficiency?

The incidence of factor XI deficiency is higher in individuals of Ashkenazi Jewish descent where it is estimated to affect 8% of the population. The severe form of the disorder is estimated to affect approximately 1 in 1,000,000 people in the general population.

Why is hemophilia B called Christmas disease?

Hemophilia B is also known as Christmas disease. It is named after the first person to be diagnosed with the disorder in 1952, Stephen Christmas. As the second most common type of hemophilia, it occurs in about 1 in 25,000 male births and affects about 4,000 individuals in the United States.

What is factor 10 called?

COAGULATION CASCADE | Factor X Factor X (fX), also called Stuart factor, is a vitamin-K dependent serine protease zymogen that is activated in the first common step of the intrinsic and extrinsic pathways of blood coagulation.

Where is thrombin found in the body?

The thrombin (prothrombin) gene is located on the eleventh chromosome (11p11-q12).

What are the 12 blood clotting factors?

The following are coagulation factors and their common names:

Factor I – fibrinogen.
Factor II – prothrombin.
Factor III – tissue thromboplastin (tissue factor)
Factor IV – ionized calcium ( Ca++ )
Factor V – labile factor or proaccelerin.
Factor VI – unassigned.
Factor VII – stable factor or proconvertin.

How is coagulation factor XI related to thrombosis?

Factor XI, a component of the intrinsic pathway of coagulation, contributes to the generation of thrombin, which is involved in both the formation of fibrin and protection against fibrinolysis. A deficiency of factor XI is associated with bleeding, but a role of high factor XI levels in thrombosis has not been investigated.

How is coagulation factor XI activated in vivo?

Factor XI is a component of the intrinsic pathway of coagulation. It can be activated in vitro by contact with a thrombogenic surface, such as glass. Whether surface contact contributes to the activation of factor XI in vivo, however, is uncertain.

How are factor XI levels determined in patients?

We determined factor XI antigen levels in the patients enrolled in the Leiden Thrombophilia Study, a large population-based, case–control study (with a total of 474 patients and 474 controls) designed to estimate the contributions of genetic and acquired factors to the risk of deep venous thrombosis.

What is the role of thrombin in the clot production?

Thrombin not only cleaves fibrinogen to fibrin, but also through the activation of factor XIII effects the cross-linking of fibrin monomers to produce a firm fibrin clot.