Nachman R L, Harpel P C
J Biol Chem. 1976 Aug 10;251(15):4512-21.
Subcellular membrane and granule fractions derived from human platelets contain immunologically identifiable alpha2-macroglobulin and alpha1-antitrypsin. These platelet-derived inhibitors show a reaction of immunologic identity when compared to alpha2-macroglobulin and alpha1-antitrypsin purified from human plasma. Further, the platelet protease inhibitors possessed a similar subunit polypeptide chain structure to their plasma counterparts as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis. Studies of the binding of radiolabeled trypsin to the various solubilized platelet subcellular fractions suggest that the granule-associated alpha2-macroglobulin and alpha1-antitrypsin, as well as membrane-associated alpha2-macroglobulin were functionally active. Quantitatively, circulating platelets contain relatively small concentrations of these inhibitors as compared to platelet-associated fibrinogen and factor VIIIAGN. Platelet protease inhibitors may modulate the protease-mediated events involved in the formation of hemostatic plugs and thrombi.
源自人血小板的亚细胞膜和颗粒组分含有可通过免疫学鉴定的α2-巨球蛋白和α1-抗胰蛋白酶。与从人血浆中纯化的α2-巨球蛋白和α1-抗胰蛋白酶相比，这些源自血小板的抑制剂显示出免疫同一性反应。此外，通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳分析确定，血小板蛋白酶抑制剂与其血浆对应物具有相似的亚基多肽链结构。对放射性标记的胰蛋白酶与各种可溶解的血小板亚细胞组分结合的研究表明，颗粒相关的α2-巨球蛋白和α1-抗胰蛋白酶以及膜相关的α2-巨球蛋白具有功能活性。从数量上看，与血小板相关的纤维蛋白原和因子VIIIAGN相比，循环血小板中这些抑制剂的浓度相对较低。血小板蛋白酶抑制剂可能调节参与止血栓和血栓形成的蛋白酶介导的事件。
