Reactions of thrombin-serpin complexes with thrombospondin.
Reactions of thrombin-serpin complexes with thrombospondin.
复制标题
凝血酶-丝氨酸蛋白酶抑制剂复合物与血小板反应蛋白的反应。
DOI：
10.1016/0003-9861(92)90249-v
复制
发表时间：
1992
影响因子：
3.9
通讯作者：
Detwiler,TC
中科院分区：
文献类型：
--
作者：
Chang,AC;Detwiler,TC
活化的血小板释放与凝血酶形成稳定复合物的蛋白质（J. J.米勒，P.C. Browne和T. C. Detwiler，生物化学，生物物理。Res. Commun.151，9-15，1988）。反应的工作模型（P.C. Browne，J. J.米勒和T. C. Detwiler，Arch.Biochem.Bioprotein.265，534-538，1988）包括凝血酶与释放的血小板蛋白酶连接蛋白的可解离复合物，导致形成不可解离的凝血酶-连接蛋白复合物，然后该复合物变成与血小板反应蛋白二硫键连接。这种二硫键连接的复合物通过二硫键的还原转化回凝血酶连接蛋白复合物。结果，允许阐述这个模型。经过较长时间的孵育或与较高浓度的凝血酶孵育后，与凝血酶敏感蛋白复合的凝血酶的量超过了二硫键还原后回收的凝血酶连接蛋白复合物的量。当反应混合物包括凝血酶-连接蛋白复合物形成的抑制剂时，观察到凝血酶-血小板反应蛋白复合物的缓慢形成。结论是凝血酶与凝血酶敏感蛋白之间存在非连接蛋白依赖性和更快的连接蛋白依赖性二硫键。凝血酶-抗凝血酶III复合物添加到活化血小板的上清液中也导致与血小板反应蛋白的复合物，表明丝氨酸蛋白酶抑制剂而不是血小板蛋白酶连接蛋白促进凝血酶掺入与血小板反应蛋白的复合物中。通过肝素亲和层析，结果表明，凝血酶-连接蛋白复合物可解离地与血小板反应蛋白之前，形成二硫键连接的复合物。这些观察结果被纳入一个更详细的反应模型。
Activated platelets release proteins that form stable complexes with thrombin (J. J. Miller, P. C. Browne, and T. C. Detwiler,Biochem. Biophys. Res. Commun.151, 9–15, 1988). A working model for the reaction (P. C. Browne, J. J. Miller, and T. C. Detwiler,Arch. Biochem. Biophys.265, 534–538, 1988) includes a dissociable complex of thrombin with released platelet protease nexin, leading to formation of a nondissociable thrombin-nexin complex that then becomes disulfide linked to thrombospondin. This disulfide-linked complex is converted back to the thrombinnexin complex by reduction of disulfide bonds. Results that allow elaboration on this model are presented. After longer periods of incubation or after incubation with higher concentrations of thrombin, the amount of thrombin complexed with thrombospondin exceeded the amount of thrombinnexin complex recovered after reduction of disulfide bonds. When the reaction mixture included inhibitors of formation of the thrombin-nexin complex, a slow formation of the thrombin-thrombospondin complex was observed. It was concluded that there is a nexin-independent as well as the faster nexin-dependent disulfide linkage of thrombin to thrombospondin. Addition of thrombin-antithrombin III complexes to the supernatant solution of activated platelets also led to complexes with thrombospondin, demonstrating that serpins other than platelet protease nexin facilitate incorporation of thrombin into complexes with thrombospondin. By heparin affinity chromatography, it was shown that thrombin-nexin complexes dissociably associate with thrombospondin prior to formation of disulfide-linked complexes. These observations are incorporated into a more detailed model of the reaction.