Factor XIII

The fibrin -stabilizing factor ( factor XIII or Laki - Lorand factor) is an enzyme and the coagulation factor portion of the blood to clot. It is composed of twice two subunits, each of two A and B. Its two normal blood plasma concentration is 10 micrograms / ml, its half-life 5-9 days.

Genetics

The two subunits of factor XIII are encoded by two different genes:

  • The gene for the A- subunit is at the 6th chromosome ( 6p25 - p24 ).
  • The gene for the B subunit is on chromosome 1 ( 1q31 - q32.1 ).

Physiology

Thrombin converts fibrinogen to fibrin. This consists of a D unit and two bound both sides to this e- units. Fibrin forms a network in which each of its E units connections to only one D- unit of another fibrin molecule has. Factor XIII is activated by thrombin as well, together with calcium and link the D- unit of the fibrin or with the E units other fibrin. This is referred to as a retraction of blood coagulation. Another important function of factor XIIIa is the fixation of fibrinolysis TAFI (thrombin Activated fibrinolysis inhibitor) and alpha-2 -antiplasmin in fibrin clot. Thus, the clot is protected from premature fibrinolysis and thus also avoided bleeding. Furthermore, binds factor XIIIa various other substrates to cell surfaces, including thrombospondin, Fibroncetin and other proteins.

Diseases

Hereditary factor XIII deficiency is extremely rare and causes a strong tendency to bleeding. Acquired deficiencies, however, are not uncommon.

Human Genome Organisation Anatomical Therapeutic Chemical Classification System Transferase Tissue factor Kallikrein
324398
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