Factor V (F5) Antibody – Sheep Polyclonal

This gene encodes an essential cofactor of the blood coagulation cascade. This factor circulates in plasma, and is converted to the active form by the release of the activation peptide by thrombin during coagulation. This generates a heavy chain and a light chain which are held together by calcium ions. The activated protein is a cofactor that participates with activated coagulation factor X to activate prothrombin to thrombin. Defects in this gene result in either an autosomal recessive hemorrhagic diathesis or an autosomal dominant form of thrombophilia, which is known as activated protein C resistance. [provided by RefSeq]

Function: Central regulator of hemostasis. It serves as a critical cofactor for the prothrombinase activity of factor Xa that results in the activation of prothrombin to thrombin.

Subunit structure: Factor Va, the activated form of factor V, is composed of a heavy chain and a light chain, non-covalently bound. The interaction between the two chains is calcium-dependent.

Subcellular location: Secreted

Tissue specificity: Plasma. Ref.18

Domain: Domain B contains 35 x 9 AA tandem repeats, and 2 x 17 AA repeats.

Post-translational modification: Thrombin activates factor V proteolytically to the active cofactor, factor Va (formation of a heavy chain at the N-terminus and a light chain at the C-terminus).Sulfation is required for efficient thrombin cleavage and activation and for full procoagulant activity.Activated protein C inactivates factor V and factor Va by proteolytic degradation.Phosphorylation sites are present in the extracelllular medium.

Involvement in disease: Defects in F5 are the cause of factor V deficiency (FA5D) [

MIM:227400]; also known as Owren parahemophilia. It is an hemorrhagic diastesis. Ref.30 Ref.33Defects in F5 are the cause of thrombophilia due to activated protein C resistance (THR-APCR) [

MIM:188055]. THR-APCR is a hemostatic disorder due to defective degradation of factor Va by activated protein C. It is characterized by a poor anticoagulant response to activated protein C resulting in tendency to thrombosis. Ref.26 Ref.31 Ref.32 Ref.34 Ref.36Defects in F5 are a cause of susceptibility to Budd-Chiari syndrome (BCS) [

MIM:600880]. It is a syndrome caused by obstruction of hepatic venous outflow involving either the hepatic veins or the terminal segment of the inferior vena cava. Obstructions are generally caused by thrombosis and lead to hepatic congestion and ischemic necrosis. Clinical manifestations observed in the majority of patients include hepatomegaly, right upper quadrant pain and abdominal ascites. Budd-Chiari syndrome is associated with a combination of disease states including primary myeloproliferative syndromes and thrombophilia due to factor V Leiden, protein C deficiency and antithrombin III deficiency. Budd-Chiari syndrome is a rare but typical complication in patients with polycythemia vera.Defects in F5 may be a cause of susceptibility to ischemic stroke (ISCHSTR) [

MIM:601367]; also known as cerebrovascular accident or cerebral infarction. A stroke is an acute neurologic event leading to death of neural tissue of the brain and resulting in loss of motor, sensory and/or cognitive function. Ischemic strokes, resulting from vascular occlusion, is considered to be a highly complex disease consisting of a group of heterogeneous disorders with multiple genetic and environmental risk factors. Ref.35

Sequence similarities: Belongs to the multicopper oxidase family.Contains 3 F5/8 type A domains.Contains 2 F5/8 type C domains.Contains 6 plastocyanin-like domains.

Sequence caution: The sequence ABD23003.1 differs from that shown. Reason: Erroneous gene model prediction. The sequence CAI23065.1 differs from that shown. Reason: Erroneous gene model prediction.