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Medical Term:


Pronunciation: throm'bin


  1. An enzyme (proteinase), formed in shed blood, that converts fibrinogen into fibrin by hydrolyzing peptides (and amides and esters) of l-arginine; formed from prothrombin by the action of prothrombinase (factor Xa, another proteinase).
  2. A sterile protein substance prepared from prothrombin of bovine origin through interaction with thromboplastin in the presence of calcium; causes clotting of whole blood, plasma, or a fibrinogen solution; used as a topical hemostatic for capillary bleeding with or without fibrin foam in general and plastic surgical procedures.

Synonym(s): factor IIa, fibrinogenase, thrombase, thrombosin

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