Role of the membrane in the inactivation of factor Va by activated protein C.
Role of the membrane in the inactivation of factor Va by activated protein C.
复制标题
DOI：
10.1016/s0021-9258(19)74243-4
复制
发表时间：
1993-12
期刊：
影响因子：
--
通讯作者：
M. Kalafatis;K. Mann
中科院分区：
文献类型：
--
作者：
M. Kalafatis;K. Mann
在存在和不存在磷脂小泡和蛋白S的情况下，用活化蛋白C(APC)灭活牛凝血因子Va。在与APC(10 NM)孵育30分钟后，膜结合的Va(200 NM)完全失活，而在没有磷脂小泡的情况下，孵育2小时后，辅因子保持其初始辅因子活性的60%。膜结合因子Va活性的完全丧失与辅因子重链上M(R)40,000，28,000和20,000个片段的出现有关，这些片段对应于Arg306，Arg505和Arg662的切割。在没有脂双分子的情况下，Arg505和Arg662的裂解导致辅因子活性降低。在磷脂小泡存在或不存在的情况下，APC对辅因子轻链的切割没有差异。在蛋白质S存在下，APC在Arg306、Arg505和Arg662处对凝血因子Va重链的裂解速率以及膜结合辅因子的失活速率都得到了提高。我们的数据表明，APC在Arg306对凝血因子Va的阴离子脂质依赖的切割是辅因子完全失活所必需的。
Bovine factor Va inactivation by activated protein C (APC) was evaluated in the presence and absence of phospholipid vesicles and protein S. Following a 30-min incubation with APC (10 nM), membrane-bound factor Va (200 nM) is completely inactivated, whereas in the absence of phospholipid vesicles, after a 2-h incubation, the cofactor retains 60% of its initial cofactor activity. The complete loss of activity of membrane-bound factor Va is associated with the appearance of M(r) 40,000, 28,000, and 20,000 fragments derived from the heavy chain of the cofactor which correspond to cleavage at Arg306, Arg505, and Arg662. In the absence of a lipid bilayer, cleavage at Arg505 and Arg662 results in a cofactor with reduced activity. No difference is observed in the cleavage of the light chain of the cofactor by APC in the presence or absence of phospholipid vesicles. The rate of the cleavage of factor Va heavy chain at Arg306, Arg505, and Arg662 as well as the rate of the membrane-bound cofactor inactivation by APC were enhanced in the presence of protein S. Our data demonstrate that the anionic lipid-dependent cleavage of factor Va by APC at Arg306 is required for the complete inactivation of the cofactor.