prothrombin

pro·throm·bin

noun \(ˌ)prō-ˈthräm-bən\

Definition of PROTHROMBIN

: a plasma protein produced in the liver in the presence of vitamin K and converted into thrombin in the clotting of blood

Origin of PROTHROMBIN

International Scientific Vocabulary

First Known Use: 1898

pro·throm·bin

noun \(ˈ)prō-ˈthräm-bən\   (Medical Dictionary)

Medical Definition of PROTHROMBIN

: a plasma protein produced in the liver in the presence of vitamin K and converted into thrombin by the action of various activators (as thromboplastin) in the clotting of blood

—pro·throm·bic \-bik\ (audio pronunciation) adjective

prothrombin

noun    (Concise Encyclopedia)

Carbohydrate-protein compound in plasma essential to coagulation. In response to bleeding, a complex series of clotting-factor interactions leads to its conversion by thromboplastin to thrombin, which transforms fibrinogen in plasma into fibrin. Fibrin and platelets combine to form a clot. Hemophilia is caused by a hereditary lack of one of the clotting factors. Vitamin K is needed to synthesize prothrombin, so conditions that impair the vitamin's absorption result in prothrombin deficiency and a tendency to prolonged bleeding.