Fibrin stabilizing factor
Fibrin stabilizing factor | ||
---|---|---|
Ribbon model of the A chain dimer of factor XIII, according to PDB 1EVU | ||
Properties of human protein | ||
Mass / length primary structure | 2670 = 2 * 694 + 2 * 641 amino acids | |
Secondary to quaternary structure | 2A + 2B | |
Cofactor | Calcium (A) | |
Precursor | A: (731 amino acids) | |
Identifier | ||
Gene names | F13A1 ; F13B | |
External IDs | ||
Drug information | ||
ATC code | B02 BD07 | |
Enzyme classification | ||
EC, category | 2.3.2.13 , transferase | |
Response type | Transfer of alkyl residues within or between proteins | |
Substrate | Xaa-Gln-Xaa + Yaa-Lys-Yaa | |
Products | Xaa-Glu (Xaa) -Lys (Yaa) -Yaa + NH 3 | |
Occurrence | ||
Homology family | Transglutaminase | |
Parent taxon | Chordates |
The fibrin-stabilizing factor ( factor XIII or Laki-Lorand factor) is an enzyme and, as a coagulation factor, part of blood coagulation . It consists of two subunits, two A and two B. Its normal concentration in the blood plasma is 10 μg / 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 on the 6th chromosome (6p25-p24): F13A1
- The gene for the B subunit is located on chromosome 1 (1q31-q32.1): F13B
physiology
Thrombin converts fibrinogen to fibrin . This consists of a D-unit and two E-units bound to it on both sides. Fibrin forms a network in which each of its E units has connections to only one D unit of another fibrin molecule. Factor XIII is also activated by thrombin, together with calcium , and links the D unit of fibrin with the E units of other fibrin molecules. This is known as the retraction phase of blood clotting. Another important function of factor XIIIa is the fixation of the fibrinolysis inhibitors TAFI (Thrombin Activated Fibrinolysis Inhibitor) and alpha-2 antiplasmin in the fibrin clot. This protects the clot from premature fibrinolysis and thus also prevents bleeding. Furthermore, factor XIIIa binds various other substrates to cell surfaces, including thrombospondin, fibronectin and other proteins.
Diseases
Hereditary factor XIII deficiency is extremely rare and causes a high tendency to bleed. Acquired deficiencies, on the other hand, are not uncommon.
literature
- K. Laki, L. Lóránd: On the Solubility of Fibrin Clots. In: Science. 108, 2802, September 1948, p. 280. doi: 10.1126 / science.108.2802.280 . PMID 17842715 .
- L. Muszbek, RA Ariëns, A. Ichinose: Factor XIII: recommended terms and abbreviations. In: J. Thromb. Haemost. 5 (1), January 2007, pp. 181-183. doi: 10.1111 / j.1538-7836.2006.02182.x . PMID 16938124 .
Web links
- A unit: fibrin stabilizing factor. In: Online Mendelian Inheritance in Man . (English)
- B unit: fibrin stabilizing factor. In: Online Mendelian Inheritance in Man . (English)