Factor IXa inhibition by protease nexin-2/amyloid beta-protein precursor on phospholipid vesicles and cell membranes.
Factor IXa inhibition by protease nexin-2/amyloid beta-protein precursor on phospholipid vesicles and cell membranes.
复制标题
蛋白酶 nexin-2/淀粉样β蛋白前体对磷脂囊泡和细胞膜的因子 IXa 抑制。
DOI：
10.1021/bi00004a010
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发表时间：
1995
期刊：
影响因子：
2.9
通讯作者：
VanNostrand,WE
中科院分区：
文献类型：
--
作者：
Schmaier,AH;Dahl,LD;Hasan,AA;Cines,DB;Bauer,KA;VanNostrand,WE
1994年11月2日接收的修订版Mandalpt ®摘要：蛋白酶连接蛋白-2/淀粉样蛋白/3-蛋白前体（PN-2/A/3 PP）是一种Kunitz型蛋白酶抑制剂，已被证明是酶、因子XIa和IXa（FIXa）的紧密结合抑制剂，表明该蛋白在止血中的作用。由于凝血反应是在生物表面上调节的，我们研究了25：75（mol/mol）磷脂酰丝氨酸/磷脂酰胆碱囊泡（PSPC）、凝血酶活化血小板或脐静脉内皮细胞如何影响FIXaby PN-2/A/3 PP的灭活。在存在PSPC、活化血小板或内皮细胞的情况下，在不存在或存在凝血酶活化因子VIII（FVIIIa）的情况下，人或猪FIXa活化人因子X的Km相似（0.05-0.39 µ）。FVIIla的存在使人和猪因子IXA激活因子X的催化效率（kCil/Km比）分别增加了4952-406倍。在PSPC存在下，PN-2/A/3 PP对人和猪FIXa的抑制作用的Ki分别为Ki = 1.9 × 10-9 M和5.8 × 10-9 M。在将FVIIa添加到反应中后，PN-2/A/3 PP对PSPC的人和猪FIXa抑制的Ki分别增加13倍和4倍至Ki = 2.5 × 10-8 M和2.4 × 10 - 8 M。这些K…当通过显色或活化肽释放试验测量因子X活化时，PN-2/A/3 PP对人FIXa对磷脂囊泡的抑制作用相似。只有在PSPC存在时，FVIIIa才能减弱PN-2/A/3 PP对FIXa的抑制作用。人和猪FIXa对PSPC的抑制作用不受FVIIIa的影响。与PSPC和FVIIIa或内皮细胞相比，活化的人血小板进一步保护人或猪FIXa免受PN-2/A/3 PP的抑制。PN-2/A/3 PP是存在组装的tenase复合物的FIXa抑制剂。
Revised Manuscript Received November 2, 1994® abstract: Protease nexin-2/amyloid/3-protein precursor (PN-2/A/3PP) is a Kunitz-type protease inhibitor which has beenshown to be a tight-binding inhibitor of enzymes, factors XIa and IXa (FIXa), suggesting a role for this protein in hemostasis. Since coagulant reactions are modulated on biologic surfaces, we investigated how 25: 75 (mol/mol) phosphatidylserine/phosphatidylcholine vesicles (PSPC), thrombinactivated platelets, or umbilical vein endothelial cells influence inactivation of FIXaby PN-2/A/3PP. The Km of human or porcine FIXa activation of human factor X in the presence of PSPC, activated platelets, or endothelial cells in the absence or presence of thrombin-activated factor VIII (FVIIIa) was similar,(0.05—0.39 µ). The presence of FVIIIa increased the catalyticefficiency (kCil/Km ratio) of human and porcine factor IXa’s activation of factor X 4952—406-fold, respectively. In the presence of PSPC, the K¡ of human and porcine FIXa inhibition by PN-2/A/3PP was K,= 1.9 x 10-9 M and 5.8 x 10-9 M, respectively. After the addition of FVUIa to the reaction, the K\for both human and porcine FIXa inhibition by PN-2/A/3PP on PSPC increased 13-and 4-fold to K,= 2.5 x 10-8 M and 2.4 x 10" 8 M, respectively. These K¡ for inhibition of human FIXa on phospholipid vesicles by PN-2/A/3PP were similar when factor X activation was measured by chromogenic or activation peptiderelease assays. FVIIIa reduced the inhibition of FIXa by PN-2/A/3PP only in thepresence of PSPC. Inhibition of human and porcineFIXa on PSPC by the isolatedKPI domain of-2/ß was not influenced by FVIIIa. Activated human platelets provide further protection of human or porcine FIXa from inhibition by PN-2/A/3PP over that seen with PSPC and FVIIIa or endothelial cells. PN-2/A/3PP is an inhibitor of FIXa in the presence of the assembled tenase complex.