Blood-clotting protein that is converted to the active form, factor IIa, or thrombin, by cleavage.
Protein in plasma involved in coagulation of blood. The prothrombin time is an index of the coagulability of blood (and hence of vitamin K nutritional status) based on the time taken for a citrated sample of blood to clot when calcium ions and thromboplastin are added.
A protein in blood which helps blood to coagulate and which needs Vitamin K to be effective.
Precursor of thrombin. The conversion of thrombin is an essential step in the clotting process.
Plasma protein that is a precursor of thrombin, a final step in blood coagulation; also called Factor II.
A plasma coagulation factor (factor II) synthesized in the liver.
A substance, present in blood plasma, that is the inactive precursor from which the enzyme thrombin is derived during the process of blood coagulation.
An inactive substance in the blood plasma that is the precursor of the enzyme, thrombin, which clots the blood. The conversion occurs when a blood vessel is damaged and the process of blood coagulation occurs.
A plasma protein coagulation factor synthesized by the liver (vitamin K is necessary) that is converted to thrombin by prothrombinase and thrombokinase (activated factor X) in the presence of calcium ions.
A glycoprotein variety known as thrombin, which undergoes conversion as part of the clotting mechanism.
A vital component found in blood plasma necessary for blood clotting. When thromboplastin and calcium are present, prothrombin undergoes a conversion into thrombin. Thrombin, in its turn, transforms fibrinogen into fibrin, which subsequently contracts to create a blood clot.