Sakata Y, Aoki N
J Clin Invest. 1980 Feb;65(2):290-7. doi: 10.1172/JCI109671.
The concentration of alpha 2-plasmin inhibitor in blood plasma is higher than that in serum obtained from the blood clotted in the presence of calcium ions, but is the same as that in serum obtained in the absence of calcium ions. Radiolabeled alpha2-plasmin inhibitor was covalently bound to fibrin only when calcium ions were present at the time of clotting of plasma or fibrinogen. Whereas, when batroxobin, a snake venom enzyme that lacks the ability to activate fibrin-stabilizing factor, was used for clotting fibrinogen, the binding was not observed. When fibrin-stablizing, factor-deficient plasma was clotted, the specific binding of alpha 2-plasmin inhibitor to fibrin did not occur even in the presence of calcium ions and the concentration of alpha 2-plasmin inhibitor in serum was the same as that in plasma. Monodansyl cadaverine, a fluorescent substrate of the fibrin-stablizing factor, was incorporated into alpha 2-plasmin inhibitor by activated fibrin-stablizing factor. All these findings indicate that alpha 2-plasmin inhibitor is cross-linked to fibrin by activated fibrin-stabilizing factor when blood is clotted. Analysis of alpha 2-plasmin inhibitor-incorporated fibrin by sodium dodecyl sulfate gel electrophoresis showed that the inhibitor was mainly cross-linked to polymerized alpha-chains of cross-linked fibrin. Cross-linking of alpha 2-plasmin inhibitor to fibrin renders fibrin clot less susceptible to fibrinolysis by plasmin.
血浆中α2 - 纤溶酶抑制剂的浓度高于在钙离子存在下血液凝固所得到的血清中的浓度，但与在无钙离子情况下得到的血清中的浓度相同。只有当血浆或纤维蛋白原在凝血时存在钙离子时，放射性标记的α2 - 纤溶酶抑制剂才会与纤维蛋白共价结合。然而，当使用缺乏激活纤维蛋白稳定因子能力的蛇毒酶巴曲酶来使纤维蛋白原凝固时，未观察到这种结合。当缺乏纤维蛋白稳定因子的血浆凝固时，即使存在钙离子，α2 - 纤溶酶抑制剂与纤维蛋白的特异性结合也不会发生，并且血清中α2 - 纤溶酶抑制剂的浓度与血浆中的浓度相同。纤维蛋白稳定因子的荧光底物单丹磺酰尸胺被激活的纤维蛋白稳定因子掺入α2 - 纤溶酶抑制剂中。所有这些发现表明，血液凝固时，α2 - 纤溶酶抑制剂通过激活的纤维蛋白稳定因子与纤维蛋白交联。通过十二烷基硫酸钠凝胶电泳对掺入α2 - 纤溶酶抑制剂的纤维蛋白进行分析表明，该抑制剂主要与交联纤维蛋白的聚合α链交联。α2 - 纤溶酶抑制剂与纤维蛋白的交联使纤维蛋白凝块对纤溶酶介导的纤维蛋白溶解更具抗性。
