- Factor XIII
protein
Name = coagulation factor XIII, A1 polypeptide
caption =
width =
HGNCid = 3531
Symbol = F13A1
AltSymbols = F13A
EntrezGene = 2162
OMIM = 134570
RefSeq = NM_000129
UniProt = P00488
PDB =
ECnumber =
Chromosome = 6
Arm = p
Band = 24
LocusSupplementaryData = .2-p23protein
Name = coagulation factor XIII, B polypeptide
caption =
width =
HGNCid = 3534
Symbol = F13B
AltSymbols =
EntrezGene = 2165
OMIM = 134580
RefSeq = NM_001994
UniProt = P05160
PDB =
ECnumber =
Chromosome = 1
Arm = q
Band = 31
LocusSupplementaryData = -q32.1Factor XIII or fibrin stabilizing factor is an
enzyme (EC number|2.3.2.13) of the blood coagulation system that crosslinksfibrin . Whenthrombin has converted fibrinogen to fibrin, the latter forms a proteinaceous network in which every E-unit is crosslinked to only "one" D-unit. Factor XIII is activated by thrombin into factor XIIIa; its activation into Factor XIIIa requires calcium as a cofactor.FXIII is known also as Laki-Lorand factor, after the scientists who first proposed its existence in 1948.Laki K, Lorand L. On the solubility of fibrin clots. "Science" 1948;108:280.] A 2005 conference recommended standardization of nomenclature.cite journal | author = Muszbek, L.| title = Factor XIII: recommended terms and abbreviations | journal = J Thromb Haemost | volume = 5| issue = | pages = 181| year = 2007| pmid = 16938124| doi = 10.1111/j.1538-7836.2006.02182.x]
Genetics
Zymogene factor XIII is a 320000 Mr glycoprotein tetramer consisting of twice two subunits (2 A and 2 B), the
gene s for which are on differentchromosome s:
* A subunit (6p25-p24). Thetransglutaminase part; this adds an alkyl group to the nitrogen on aglutamine residue, which binds in turn with alysine on the other chain. The molecular weight of the A chain is approximately 83000.
* B subunit (1q31-q32.1). This has no clear enzymatic activity, and may serve as a carrier for the A subunit. The molecular weight of the B chain is approximately 76500.Physiology
Typical concentrations of FXIII in plasma is 10 μg/ml (2A2B heterodimer), while the concentration of free B chain is 22 μg/ml. FXIII has a long half life, ranging from 5-9 days. It is present in plasma,
platelet s, andmonocyte s, as well asmacrophage s and bone marrow precursors of these cell types.A clot that has not been stabilized by FXIIIa is soluble in 5 mol/L
urea , while a stabilized clot is resistant to this phenomenon.Diagnostic use
Factor XIII levels are not measured routinely, but may be considered in patients with an unexplained bleeding tendency. As the enzyme is quite specific for monocytes and macrophages, determination of the presence of factor XIII may be used to identify and classify malignant diseases involving these cells.
ee also
*
Factor XIII deficiency
*D-dimer References
External links
* [http://www.hemophilia.org/bdi/bdi_types11.htm Factor XIII deficiency at hemophilia.org]
*
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