Takada A, Takada Y
Thromb Res. 1985 Oct 15;40(2):171-9. doi: 10.1016/0049-3848(85)90327-5.
Glu-plasminogen (Glu-plg) was incubated with plasmin. It took more than 2 hr incubation for the conversion of Glu-plg to a modified form (Lys-plg) to take place. Especially the conversion of Glu-plg II to Lys-plg II by plasmin took place very slowly. On the other hand, the conversion of Glu-plg I to Lys-plg I took place faster than that of Glu-plg II. In the presence of 1 mM tranexamic acid, the conversion of both Glu-plg I and II to their Lys-forms by plasmin was accelerated and completed in 30 min incubation. Fifty percent increase in the rate of the conversion of Glu-plg I to Lys-plg I was observed in the presence of 0.18 mM tranexamic acid. For the conversion of Glu-plg II to Lys-plg II, larger concentration of tranexamic acid was needed. Another observation was that tranexamic acid protected the degradation of plasminogen by plasmin, indicating the involvement of the lysine binding sites (LBS) of plasmin in the proteolytic attack against plg.
将谷氨酸纤溶酶原（Glu-plg）与纤溶酶一起孵育。Glu-plg转化为修饰形式（赖氨酸纤溶酶原，Lys-plg）需要超过2小时的孵育时间。特别是纤溶酶将Glu-plg II转化为Lys-plg II的过程非常缓慢。另一方面，Glu-plg I转化为Lys-plg I的速度比Glu-plg II快。在存在1 mM氨甲环酸的情况下，纤溶酶将Glu-plg I和II转化为其赖氨酸形式的过程加速，并在孵育30分钟后完成。在存在0.18 mM氨甲环酸的情况下，观察到Glu-plg I转化为Lys-plg I的速率增加了50%。对于Glu-plg II转化为Lys-plg II，需要更高浓度的氨甲环酸。另一个观察结果是氨甲环酸可保护纤溶酶原不被纤溶酶降解，这表明纤溶酶的赖氨酸结合位点（LBS）参与了对纤溶酶原的蛋白水解攻击。
