prothrombin: Quick Facts

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Also Known As	factor II

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The blood coagulation cascade. Each protein circulates in the blood in an active form.

Red blood cells (erythrocytes) trapped in a mesh of fibrin threads. The glycoprotein prothrombin, which occurs in blood plasma, is transformed into thrombin by a clotting factor known as factor X or prothrombinase; thrombin then acts to transform fibrinogen, also present in plasma, into fibrin, which, in combination with platelets from the blood, forms a blood clot.

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glycoprotein coagulation factor colony-stimulating factor Myoglobin hemagglutinin fibrin Intrinsic factor Nucleoprotein