QUANTITATIVE CHARACTERIZATION OF THE BINDING OF PLASMINOGEN TO INTACT FIBRIN CLOTS, LYSINE-SEPHAROSE, AND FIBRIN CLEAVED BY PLASMIN
QUANTITATIVE CHARACTERIZATION OF THE BINDING OF PLASMINOGEN TO INTACT FIBRIN CLOTS, LYSINE-SEPHAROSE, AND FIBRIN CLEAVED BY PLASMIN
复制标题
DOI：
10.1021/bi00334a031
复制
发表时间：
1985-01-01
期刊：
影响因子：
2.9
通讯作者：
MANGEL, WF
中科院分区：
文献类型：
--
作者：
BOK, RA;MANGEL, WF
人谷氨酸和赖氨酸纤溶酶原的结合完整的纤维蛋白凝块，赖氨酸琼脂糖凝胶，和纤维蛋白裂解纤溶酶的定量特征。在完整的纤维蛋白凝块上，有1个Glu-纤溶酶原的强结合位点，Kd为25 μ M，和1个Lys-纤溶酶原的强结合位点，Kd为7.9 μ M。在这两种情况下，每个纤维蛋白单体的纤溶酶原结合位点的数量均为1。观察到Glu-纤溶酶原的弱得多的结合位点，Kd为NS 350 μ M。纤溶酶对纤维蛋白的有限消化产生了纤溶酶原的额外结合位点，其Kd值类似于纤溶酶原与赖氨酸-琼脂糖的结合。这是可预测的，因为纤溶酶原与赖氨酸-琼脂糖结合，并且可以用ε-洗脱。氨基己酸和纤溶酶优先在赖氨酰残基的羧基侧切割纤维蛋白，因为赖氨酸-琼脂糖凝胶中赖氨酰部分的结构和ε-氨基己酸的结构不同。氨基己酸与纤溶酶裂解纤维蛋白产生的COOH末端赖氨酰残基的结构相同。Glu-纤溶酶原与赖氨酸-琼脂糖结合的Kd为43 μ M，被纤溶酶部分裂解的纤维蛋白的Kd为48 μ M。Lys-纤溶酶原与赖氨酸-琼脂糖结合的Kd为30 μ M。在纤维蛋白被纤溶酶部分切割的情况下，存在两种类型的Lys-纤溶酶原结合位点，一种具有7.6 μ M的Kd，另一种具有44 μ M的Kd。纤溶酶产生的纤溶酶原结合位点作为加速凝块破坏的机制可能是生理相关的，并且因为由纤溶酶在赖氨酰残基处裂解产生的纤维蛋白和其他蛋白质的片段将靶向于在循环系统中的任何地方的破坏。纤维蛋白酶是人尿激酶激活纤溶酶原的正性调节因子。经过一段时间的滞后期后，大概是由于凝块的致密纤维基质的扩散阻抗，与不存在或存在纤维蛋白原的情况相比，在纤维蛋白存在下Glu-纤溶酶原的活化速率迅速加速。
The binding of human Glu- and Lys-plasminogens to intact fibrin clots, to lysine-Sepharose, and to fibrin cleaved by plasmin was quantitatively characterized. On intact fibrin clots, there was 1 strong binding site for Glu-plasminogen with Kd of 25 .mu.M and 1 strong binding site for Lys-plasminogen with a Kd of 7.9 .mu.M. In both cases, the number of plasminogen binding sites per fibrin monomer was 1. A much weaker binding site for Glu-plasminogen was observed with a Kd of NS 350 .mu.M. Limited digestion of fibrin by plasmin created additional binding sites for plasminogen with Kd values similar to the binding of plasminogen to lysine-Sepharose. This was predictable given that plasminogen binds to lysine-Sepharose and can be eluted with .epsilon.-aminocaproic acid and that plasmin preferentially cleaves fibrin at the carboxy side of lysyl residues, because the structures of the lysyl moiety in lysine-Sepharose and of .epsilon.-aminocaproic acid are identical with the structure of a COOH-terminal lysyl residue created by plasmin cleavage of fibrin. The Kd for the binding of Glu-plasminogen to lysine-Sepharose was 43 .mu.M and for fibrin partially cleaved by plasmin 48 .mu.M. The Kd for the binding of Lys-plasminogen to lysine-Sepharose was 30 .mu.M. With fibrin partially cleaved by plasmin, there were 2 types of binding sites for Lys-plasminogen, 1 with a Kd of 7.6 .mu.M and the other with a Kd of 44 .mu.M. Plasmin-created plasminogen binding sites may be physiologically relevant as a mechanism for accelerating clot destruction and because fragments of fibrin and other proteins created by plasmin cleavage at lysyl residues would be targeted for destruction anywhere in the circulatory system. Fibrin was a positive regulator of the activation of plasminogen by human urokinase. After a lag period, presumably due to impedance of diffusion by the dense, fibrous matrix of the clot, the rate of activation of Glu-plasminogen rapidly accelerated in the presence of fibrin, compared to in its absence or in the presence of fibrinogen.