Change in fibrin stabilizing activity of factor XIII A subunit (FXIII-A) caused by a specific mutation, Val34Leu, is recently implicated to incidences of pathophysiology of thrombosis. In an effort to understand the effect of Val34Leu on enhanced catalytic role of FXIII-A, wild type human factor XIII A (HFXIII-A) and mutant HFXIII-A: HFXIII-A (V34L), HFXIII-A (V35L) and HFXIII-A (V34L/V35L) cDNA were expressed in E.coli system where the purified recombinant FXIII-A (gammaFXIII-A) showed a similar specific transglutaminase activity comparable to the human native FXIII-A from platelet. Using these gammaFXIII-A mutants, the activation kinetics by thrombin and the enzymatic properties of the activated gammaFXIII-A were characterized. gammaFXIII-A (V34L) and gammaFXIII-A (V34L/V35L) mutants were activated by thrombin much faster than those of wild type gammagFXIII-A and V35L variant. However, the activated gammaFXIII-A and mutants showed the identical catalytic efficiency as measured by in vitro assay. These results suggest that ready activation caused by a specific mutation of neighboring thrombin cleavage site(s) in the activation peptide of FXIII-A like V34L resulted in the real-time amount of the activated factor XIII-A that could influence the outcome of fibrin stabilization in vivo such as alpha2-plasmin inhibitor crosslinking to fibrin, a reaction known to be dependent on the initial concentration of active factor-XIII-A.

中文翻译：

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Val34Leu和Val35Leu多态性对凝血因子XIII-A酶活性的影响。

最近，由特定突变Val34Leu引起的因子XIII A亚基（FXIII-A）纤维蛋白稳定活性的变化与血栓形成的病理生理学发生率有关。为了了解Val34Leu对FXIII-A，野生型人类因子XIII A（HFXIII-A）和突变体HFXIII-A的增强催化作用的影响：HFXIII-A（V34L），HFXIII-A（V35L）和HFXIII -A（V34L / V35L）cDNA在大肠杆菌系统中表达，其中纯化的重组FXIII-A（gammaFXIII-A）显示出与血小板中人天然FXIII-A相当的相似的特异性转谷氨酰胺酶活性。使用这些gammaFXIII-A突变体，表征了凝血酶的活化动力学和活化的gammaFXIII-A的酶性质。凝血酶激活gammaFXIII-A（V34L）和gammaFXIII-A（V34L / V35L）突变体的速度比野生型gammagFXIII-A和V35L变异体快得多。但是，活化的gammaFXIII-A和突变体显示出与体外测定相同的催化效率。这些结果表明，由FXIII-A激活肽（如V34L）中相邻凝血酶切割位点的特定突变引起的即刻激活可实时产生可能影响血纤蛋白结果的激活因子XIII-A。体内稳定作用，例如α2-纤溶酶抑制剂交联到纤维蛋白上，这种反应已知取决于活性因子-XIII-A的初始浓度。