Interaction of coagulation factor V and factor Va with platelets.
Interaction of coagulation factor V and factor Va with platelets.
复制标题
凝血因子 V 和因子 Va 与血小板的相互作用。
DOI：
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发表时间：
1979
影响因子：
4.8
通讯作者：
K. Mann
中科院分区：
文献类型：
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作者：
P. Tracy;J. Peterson;M. Nesheim;F. Mcduffie;K. Mann
使用纯化单链血浆因子V的抗血清比较牛血小板和血浆因子V，并使用用相同抗血清开发的放射免疫测定法确定与牛血小板相关的因子V的量。使用放射免疫测定法和免疫扩散法作为比较技术，牛血小板因子V与牛血浆因子V在免疫化学上无法区分。血小板因子V的放射免疫测定定量表明存在593 + 139个因子V分子/血小板。牛血小板中存在的因子V的量的生物测定评估给出了与此类似的值（666 f 124），进一步表明血小板和血浆衍生的因子V是相同的。还测量了iz 51-因子V和-因子Va与血小板的结合。当与洗涤过的牛血小板孵育时，1251-因子Va经历饱和和可交换结合。存在高亲和力结合位点，约900个因子Va分子与之结合/血小板，表观解离常数为3 × 10 - 4 M，以及亲和力稍低的结合位点（Zb = 3 × 10 - 4 M），多达3500个因子Va分子与之结合/血小板。因子V与血小板的结合也是可饱和和可交换的。大约800个因子V分子以3 × 10 - 1 M的解离常数与单一类别的位点结合。交换研究表明，因子V和因子Va都结合到较低亲和力位点;然而，因子V不结合到高亲和力因子Va结合位点。凝血酶诱导的血小板活化不需要，也没有任何影响，无论是因子V或因子Va的结合。与血小板结合的因子V分子的数量与结合到低亲和力血小板结合位点的因子V分子的数量相似，并且该值也与高亲和力因子Va结合位点的数量相似。
Bovine platelet and plasma Factor V were compared using antisera raised to purified single chain plasma Factor V and the quantity of Factor V associated with the bovine platelet was established using a radioimmunoassay developed with the same antisera. Bovine platelet Factor V is immunochemically indistinguishable from bovine plasma Factor V using both radioimmunoassay and immunodiffusion as comparative techniques. Radioimmunoassay quantitation of platelet Factor V indicated that 593 + 139 Factor V molecules were present/platelet. Bioassay assessment of the quantity of Factor V present in the bovine platelet gave a value similar to this (666 f 124), further suggesting that the platelet and plasma derived Factor V are identical. The binding of both iz51-Factor V and -Factor Va to platelets was also measured. When incubated with washed bovine platelets, 1251-Factor Va underwent saturable and exchangeable binding. There are high affinity binding sites to which approximately 900 Factor Va molecules are bound/platelet with an apparent dissociation constant of 3 x lo-” M, as well as binding sites of slightly lower affinity (Z& = 3 X lo-’ M) to which as many as 3500 Factor Va molecules are bound/platelet. The binding of Factor V to platelets is also saturable and exchangeable. Approximately 800 Factor V molecules bind to a single class of sites with a dissociation constant of 3 x lo-’ M. Exchange studies indicated that Factor V and Factor Va both bind to the lower affinity sites; however, Factor V does not bind to the high affinity Factor Va binding sites. Thrombin-induced platelet activation was not required for, nor had any effect on, the binding of either Factor V or Factor Va. The number of Factor V molecules associated with the platelet is similar to the number of Factor V molecules bound to the low affinity platelet binding sites, and that value is also similar to the number of high affinity Factor Va binding sites.