Search results
Results From The WOW.Com Content Network
Thromboplastin (TPL) is derived from cell membranes and is a mixture of both phospholipids and tissue factor, neither of which are enzymes.Thromboplastin acts on and accelerates the activity of Factor Xa, also known as thrombokinase, [1] aiding blood coagulation through catalyzing the conversion of prothrombin to thrombin.
Tissue factor, also called platelet tissue factor or Coagulation factor III, [5] is a protein present in subendothelial tissue and leukocytes which plays a major role in coagulation and, in humans, is encoded by F3 gene. Its role in the blood clotting is the initiation of thrombin formation from the zymogen prothrombin.
Factor XI, or plasma thromboplastin antecedent, is the zymogen form of factor XIa, one of the enzymes involved in coagulation. Like many other coagulation factors, it is a serine protease . In humans, factor XI is encoded by F11 gene .
An alternative name for the factor is plasma thromboplastin component, given by an independent group in California. [66] Hageman factor, now known as factor XII, was identified in 1955 in an asymptomatic patient with a prolonged bleeding time named of John Hageman. Factor X, or Stuart-Prower factor, followed, in 1956.
Fresh normal plasma has all the blood coagulation factors with normal levels. If the problem is a simple factor deficiency, mixing the patient plasma 1:1 with plasma that contains 100% of the normal factor level results in a level ≥50% in the mixture (say the patient has an activity of 0%; the average of 100% + 0% = 50%). [3]
Coagulation factor X (EC 3.4.21.6), or Stuart factor, is an enzyme of the coagulation cascade, encoded in humans by F10 gene. [5] It is a serine endopeptidase (protease group S1, PA clan). Factor X is synthesized in the liver and requires vitamin K for its synthesis.
Factor XII does play an important role in clot formation during in vitro measurements of the partial thromboplastin time, which causes these measurements to be markedly prolonged in patients with factor XII deficiency, usually well beyond even what is seen in hemophilia A, hemophilia B, or factor XI deficiency. [19]
Haemophilia C (also known as plasma thromboplastin antecedent (PTA) deficiency or Rosenthal syndrome) is a mild form of haemophilia affecting both sexes, due to factor XI deficiency. [4] It predominantly occurs in Ashkenazi Jews. It is the fourth most common coagulation disorder after von Willebrand's disease and haemophilia A and B.