Terminal steps of coagulation pathway

Factor XIII is present in both plasma and platelets. Plasma factor XIII is a 320 kDa tetramer, composed of two (70 kDa) a-chains, and two (90 kDa) /i-chains. The platelet form of factor XIII 

Glutamine side-chain of one fibrin molecule y-Amide E-amino Lysine side-chain of another fibrin molecule 

In the case of platelet-derived factor XIII, the resultant product (a )2, is the activated form. Thrombin action on plasma-derived factor XIII generates an a 2jfi2 dimer, which is devoid of transglutaminase activity. However, in the presence of Ca +, the a P chains dissociate, yielding the biologically active a 2. 

Helixate NexGen (rhFactor VIII) Bayer Haemophilia A 

NovoSeven (rhFactor Vila) Novo-Nordisk Some forms of haemophilia 

Prothrombin (factor II) is a 582 amino acid, 72.5 kDa glycoprotein, which represents the circulating zymogen of thrombin (Ha). It contains up to six y-carboxyglutamate residues towards its N-terminal end, via which it binds several Ca2+ ions. Binding of Ca2+ facilitates prothrombin binding to factor Xa at the site of vascular injury. The factor Xa complex then proteolytically 

CH12 RECOMBINANT BLOOD PRODUCTS AND THERAPEUTIC ENZYMES 

Fibrinogen (factor I) is a large (340 kDa) glycoprotein consisting of two identical tri-polypeptide units, a, P and y. Its overall structural composition may thus be represented as (a P y)2. 

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