Efficacy of soluble phospholipids in the prothrombinase reaction.
Efficacy of soluble phospholipids in the prothrombinase reaction.
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可溶性磷脂在凝血酶原酶反应中的功效。
DOI：
10.1021/bi047655n
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
Nelsestuen,GaryL
中科院分区：
文献类型：
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作者：
Stone,MatthewD;Nelsestuen,GaryL
凝血酶原酶复合物由一种酶（因子Xa）和一种辅因子（因子Va）组成，它们各自在外周与含有磷脂酰丝氨酸（PS）的膜结合并激活底物凝血酶原。膜促进凝血酶原酶的催化功效增强的机制尚不确切，但通常归因于膜的多位点表面上的酶和底物组装的某些方面。最近的一项提议提出了一种完全不同的作用，其中单个磷脂分子，无论是在膜中还是作为单个可溶性分子，都通过完全变构机制起作用，该机制不涉及膜的多位点特征[Zhai，X.，斯里瓦斯塔瓦，A.，德拉蒙德湾C.对所述化合物进行修饰，Daleke，D.，和Lentz，B. R.（2002）Biochemistry 41，5675 - 5684]。我们的研究测量凝血酶原活性的磷脂，如短链磷脂酰丝氨酸和溶血磷脂酰丝氨酸（溶血PS）的存在下。两者都增强凝血酶原酶活性，并且这种增加与扩展双层结构的要求一致。即使这样，凝血酶原酶的活性低时，与PS和磷脂酰胆碱（PC）的混合双层膜上的活性相比。Lyso-PS只有在与PC双层膜混合时才接近PS/PC膜的活性。结果表明，二维膜双层表面是必要的支持充分凝血酶原酶活性。
The prothrombinase complex is comprised of an enzyme, factor Xa, and a cofactor, factor Va, that each bind peripherally to membranes containing phosphatidylserine (PS) and activate the substrate, prothrombin. The mechanism by which the membrane contributes to enhanced catalytic efficacy of prothrombinase is not precisely known but is generally attributed to some aspect of enzyme and substrate assembly on the multisite surface of the membrane. A recent proposal has suggested a radically different role in which individual phospholipid molecules, either in the membrane or as single soluble molecules, act by an entirely allosteric mechanism that does not involve the multisite feature of the membrane [Zhai, X., Srivastava, A., Drummond, D. C., Daleke, D., and Lentz, B. R. (2002)Biochemistry 41, 5675−5684]. Our study measured prothrombinse activity in the presence of phospholipids such as short-chain phosphatidylserine and lysophosphatidylserine (lyso-PS). Both enhanced prothrombinase activity, and the increase was consistent with the requirement for extended bilayer structure. Even then, prothrombinase activity was low when compared with activity on bilayer membranes of mixed PS and phosphatidylcholine (PC). Lyso-PS approached the activity of PS/PC membranes only when it was mixed with PC bilayers. The results suggest that the two-dimensional membrane bilayer surface is necessary for the support of full prothrombinase activity.