Definition
Definition
Thrombin is an enzyme that has the ability to transform fibrinogen into fibrin, and which appears in the blood during coagulation.
Symptoms
physiology
Fibrinogen is the protein precursor of fibrin , synthesized by the liver . Fibrin is an insoluble protein that forms the majority of a blood clot. It results from the cleavage of fibrinogen by thrombin during blood coagulation.
Thrombin is an enzyme (a type of protein that enables certain biochemical reactions in the body), which is produced by the activation of prothrombin by thromboplastin, provided that there are calcium ions (calcium atoms that have lost two electrons) and other types of proteins, called accelerators, which are:
- The accelerin.
- La proconvertine.
In other words, thrombin is an enzyme whose main function is to convert fibrinogen into fibrin, the final step in the plasma coagulation process, that is, the coagulation of the liquid part of the blood. To understand the process involving thrombin, it is necessary to know that another protein, prothrombin, is the precursor to thrombin. Indeed, in the presence of vitamin K in the blood, prothrombin is synthesized and then activated to produce thrombin, thanks to the action of another protein: coagulation factor X. This factor is activated only if calcium is present in the blood , and another factor called activated factor V acts as a catalyst (a chemical substance that significantly alters the rate of a chemical reaction).
Medical exam
Labo
Thrombin time is the clotting time of decalcified plasma (blood stripped of its calcium) to which calcium has been subsequently added, thus containing an excess of thrombin. Thrombin is used in the thrombin time test , which assesses fibrin formation during blood clotting. A solution containing thrombin can also be used topically.
- Le thrombin time, is therefore the clotting time of blood plasma in the presence of thrombin. This depends on the quantities of fibrinogens present in the blood, but also d'antithrombin, and d'heparin contained in the plasma. This time is normally 2 to 4 seconds.
- Le Crosby test or thrombin test, is a test during which the Red cells patients with Marchiafava-Micheli disease have burst (hemolysis), and by a serum (liquid part of the blood) normal to which acid thrombin has been added.
Cause
Cause
The blood level of prothrombin decreases when:
- There is a congenital deficiency, and especially an acquired deficiency, in the case of liver disease (affecting the liver), or obstruction of the bile ducts.
- The patient receives anticoagulants in tablet form (oral).
To correct this decrease, it is necessary to provide vitamin K , or concentrates rich in factor II, factor VII, factor IX, and factor X.
Related Terms and Articles
See also
- Bile acid
- Afibrinogenemia
- Circulating anticoagulant
- Phospholipids (anti-phospholipid antibodies)
- Antithrombin deficiency
- anticoagulant
- Gallstone
- Calcium
- Coagulation
- Crosby Test
- enzymes
- Fibrin
- Fibrinogen
- Hageman Factor
- Leiden Factor V
- Marchiafava-Bignami disease
- Red thrombus
- Thrombin time
- Thrombus
- Prothrombin time
- Gall bladder
- Vitamin K: Food Sources
- Von Willebrand Factor
- Constitutional or congenital hypoaccelerinemia
- Accelerin
- Factor V resistance to protein C
- Convertine