transglutaminase

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coagulation

 [ko-ag″u-la´shun]
1. in surgery, the disruption of tissue by physical means to form an amorphous residuum, as in electrocoagulation or hotocoagulation.
2. in colloid chemistry, solidification of a sol into a gelatinous mass.
blood coagulation clotting.
diffuse intravascular coagulation (disseminated intravascular coagulation (DIC)) see disseminated intravascular coagulation.
coagulation factors factors essential to normal blood clotting, whose absence, diminution, or excess may lead to abnormality of the clotting. Twelve factors, commonly designated by Roman numerals, have been described (I–V and VII–XIII; VI is no longer considered to have a clotting function). (See table 6.)

Factor I is a high-molecular-weight plasma protein that is converted to fibrin through the action of thrombin; deficiency conditions are called afibrinogenemia and hypofibrinogenemia. Called also fibrinogen. Factor II is a glycoprotein present in the plasma that is converted into thrombin in the common pathway of coagulation; deficiency is called hypoprothrombinemia. Called also prothrombin. Factor III is involved in the extrinsic pathway of coagulation, activating factor X; called also tissue thromboplastin or factor.

Factor IV is calcium, required in many stages of blood clotting. Factor V is a heat- and storage-labile material, present in plasma and not in serum and is involved in the intrinsic and extrinsic pathways of coagulation, causing the cleavage of prothrombin to the active thrombin. Deficiency causes parahemophilia. Called also accelerator globulin or factor and proaccelerin. Factor VI is no longer considered in the scheme of hemostasis, and hence is assigned neither a name nor a function.

Factor VII is a heat- and storage-stable material, present in serum and in plasma and participating in the extrinsic pathway of coagulation, acting with factor III to activate factor X. Deficiency, either hereditary or acquired (vitamin k deficiency), leads to hemorrhagic tendency. Called also proconvertin and serum prothrombin conversion accelerator (SPCA). Factor VIII is a relatively storage-labile material that participates in the intrinsic pathway of coagulation, acting as a cofactor in the activation of factor X. Deficiency, an X-linked recessive trait, results in hemophilia a (classical hemophilia). Called also antihemophilic factor (AHF) and antihemophilic globulin (AHG). Factor IX is a relatively storage-stable substance involved in the intrinsic pathway of coagulation, acting to activate factor X. Deficiency of this factor results in a hemorrhagic syndrome called hemophilia b (or Christmas disease), which is similar to classical hemophilia A. It is treated with purified preparations of the factor, derived from human plasma or recombinant, or with factor IX complex. Called also plasma thromboplastin component (PTC) and antihemophilic factor B.

Factor X is a heat-labile material with some storage stability, which is involved in both intrinsic and extrinsic pathways of coagulation, uniting them to begin the common pathway. Once activated, it complexes with calcium, phospholipid, and activated factor V to form prothrombinase, which cleaves and activates prothrombin to thrombin. Called also Stuart or Stuart-Prower factor. Factor XI is a stable factor involved in the intrinsic pathway of coagulation, activating factor IX. Deficiency results in hemophilia c. Called also plasma thromboplastin antecedent (PTA) and antihemophilic factor C. Factor XII is a stable factor activated by contact with glass or other foreign substances, which initiates coagulation through the intrinsic pathway by activating factor XI; called also Hageman factor. Factor XIII is a factor that polymerizes fibrin monomers, enabling fibrin to form a firm blood clot. Deficiency causes a clinical hemorrhagic diathesis. Called also fibrin-stabilizing factor.

trans·glu·ta·min·ase

(tranz'glū-ta'min-ās),
A group of enzymes that catalyze the calcium-dependent acyl transfer reaction in which the amide moiety of peptide-bound glutaminyl residues serve as acyl donor; a specific transglutaminase covalently cross-links fibrin molecules between glutamine and the ε-amino group of a lysyl residue, thus producing a more stable fibrin clot; another transglutaminase participates in the formation of the chemically resistant envelope of the stratum corneum during terminal differentiation of keratinocytes.

transglutaminase

/trans·glu·tam·in·ase/ (trans″gloo-tam´in-ās) an enzyme, formed by cleavage and activation of protransglutaminase, which forms stabilizing covalent bonds within fibrin strands. It is the activated form of coagulation factor XIII.

transglutaminase

the activated form of protransglutaminase, which forms stabilizing covalent bonds within fibrin strands; called also coagulation factor XIIIa.