Science Fair Project Encyclopedia
Factor XIII or fibrin stabilizing factor is an enzyme (EC 220.127.116.11) of the blood coagulation system that crosslinks fibrin. When thrombin 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.
- A subunit (6p25-p24). The transglutaminase part; this adds an alkyl group to the nitrogen on a glutamine residue, which binds in turn with a lysine on the other chain.
- B subunit (1q31-q32.1). This has no clear enzymatic activity, and may serve as a carrier for the A subunit.
Role in disease
Factor XIII deficiency may occur very rarely, and can cause a severe bleeding tendency.
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