A monoclonal antibody directed against the high-affinity lysine-binding site (LBS) of human plasminogen. Role of LBS in the regulation of fibrinolysis.
A monoclonal antibody directed against the high-affinity lysine-binding site (LBS) of human plasminogen. Role of LBS in the regulation of fibrinolysis.
复制标题
一种针对人纤溶酶原高亲和力赖氨酸结合位点 (LBS) 的单克隆抗体。
DOI：
10.1111/j.1432-1033.1986.tb09638.x
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
D. Collen
中科院分区：
文献类型：
--
作者：
P. Holvoet;H. Lijnen;D. Collen
用人纤溶酶-α2-抗纤溶酶复合体免疫30只小鼠，发现其中一株是针对纤溶酶原高亲和力赖氨酸结合部位的。事实上，这种抗体(MA-HAL)与纤溶酶原和由前三个三环结构组成的纤溶酶原片段(LBS I)反应，并被6-氨基己酸取代(25微米时置换50%)。在竞争性放射免疫分析中，2.3微米的α2-抗纤溶酶或1.3微米富含组氨酸的糖蛋白使放射性标记的纤溶酶原与MA-HAL的结合率降低到50%，这与这些配体与纤溶酶原的高亲和力赖氨酸结合部位之间的已知解离常数相一致。在无CNBr消化的纤维蛋白原的情况下，MA-HAL不影响组织型纤溶酶原激活剂对纤溶酶原的激活，但取消了CNBr消化的纤维蛋白原对反应的米氏常数的影响。MA-HAL使纤溶酶与α2-抗纤溶酶的反应速度降低20倍，并取消了纤溶酶原与纤维蛋白的结合。这些结果表明，MA-HAL特异性地结合并掩盖了纤溶酶原高亲和力赖氨酸结合部位。因此，在纤维蛋白刺激的纤溶酶原激活和抑制产生的纤溶酶的水平上，研究这种结构在纤溶调节中的作用是一个有用的工具。
One of thirty murine monoclonal antibodies, raised by immunization with human plasmin-alpha 2-antiplasmin complex, was found to be directed against the high-affinity lysine-binding site in plasminogen. Indeed, this antibody (MA-HAL) reacted with plasminogen and with a fragment of plasminogen composed of the first three triple-loop structures (LBS I) and was displaced by 6-aminohexanoic acid (50% displacement at 25 microM). In competitive radioimmunoassays the binding of radiolabeled plasminogen to MA-HAL was reduced to 50% with 2.3 microM alpha 2-antiplasmin or 1.3 microM histidine-rich glycoprotein, which corresponds to the known dissociation constants between these ligands and the high-affinity lysine-binding site of plasminogen. MA-HAL did not influence the activation of plasminogen by tissue-type plasminogen activator in the absence of CNBr-digested fibrinogen, but abolished the effect of CNBr-digested fibrinogen on the Michaelis constant of the reaction. MA-HAL reduced the reaction rate between plasmin and alpha 2-antiplasmin by a factor 20 and abolished the binding of plasminogen to fibrin. These results indicate that MA-HAL specifically binds to and masks the high-affinity lysine-binding site of plasminogen. It therefore is a useful tool for the investigation of the role of this structure in the regulation of fibrinolysis, both at the level of fibrin-stimulated activation of plasminogen and of the inhibition of generated plasmin.