Human coagulation factor Va is a cofactor for the activation of protein C.
Human coagulation factor Va is a cofactor for the activation of protein C.
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人凝血因子 Va 是激活蛋白 C 的辅助因子。
DOI：
10.1073/pnas.80.6.1584
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发表时间：
1983
影响因子：
11.1
通讯作者：
Majerus,PW
中科院分区：
文献类型：
--
作者：
Salem,HH;Broze,GJ;Miletich,JP;Majerus,PW
在体外凝血过程中，蛋白C部分转化为蛋白Ca，蛋白Ca反过来使因子Va失活。这可通过凝血块形成后因子Va凝血活性的快速失活来证明，凝血块形成与因子Va的Mr 110，000肽的裂解有关。当外源性因子Va被添加到血清中，它是灭活后，只有滞后10-20分钟。使用纯化的凝血因子在EDTA的存在下，我们证明，因子Va增强凝血酶的蛋白C激活率的50倍。反应中Va因子的Km为14 nM，比Xa因子加速血小板表面凝血酶原活化的Km高100倍。通过这种机制，因子Va可以作为促凝血剂，并通过蛋白C的活化和随后因子Va和因子VIIIa的失活来限制凝血过程的传播。
During blood clotting in vitro, protein C is converted in part to protein Ca, Protein Ca, in turn, inactivates factor Va. This is evidenced by the rapid inactivation of factor Va coagulant activity after clot formation which is associated with the cleavage of the Mr 110,000 peptide of factor Va. When exogenous factor Va is added to serum, it is inactivated only after a lag of 10-20 min. Using purified coagulation factors in the presence of EDTA, we demonstrated that factor Va enhances the rate of protein C activation by thrombin by 50-fold. The Km for factor Va in the reaction is 14 nM, 100 times higher than its Km for accelerating platelet surface prothrombin activation by factor Xa. By this mechanism, factor Va can act as a procoagulant as well as limit dissemination of the coagulation process through the activation of protein C and the subsequent inactivation of both factor Va and factor VIIIa.