Activation of human plasminogen by an insoluble derivative of urokinase. Structural changes of plasminogen in the course of activation to plasmin and demonstration of a possible intermediate compound.
Activation of human plasminogen by an insoluble derivative of urokinase. Structural changes of plasminogen in the course of activation to plasmin and demonstration of a possible intermediate compound.
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尿激酶的不溶性衍生物激活人纤溶酶原。
DOI：
10.1111/j.1432-1033.1973.tb02880.x
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发表时间：
1973
期刊：
影响因子：
--
通讯作者：
P. Wallén
中科院分区：
文献类型：
--
作者：
B. Wiman;P. Wallén
通过将纤溶酶原溶液灌注通过装有不溶性尿激酶的小柱来激活纤溶酶原。立即将流出物收集在过量的纤溶酶抑制剂（对硝基苯基对胍基苯甲酸酯）中。这实际上提供了对纤溶酶形成的瞬时抑制，并且自催化降解因此被减少到最低限度。通过改变灌注速率获得不同程度的激活。
十二烷基硫酸盐-聚丙烯酰胺电泳、氨基酸和NH2末端氨基酸分析表明，人纤溶酶原的激活涉及至少两个肽键的裂解，第一个事件是从NH2末端释放出64个氨基酸残基的肽。形成分子量约86000、NH2末端氨基酸为甲硫氨酸的中间无活性产物。第二个位点的裂解导致形成具有通过二硫桥连接的两条链的分子。一条分子量约为 63000 的链对其 NH2 末端部分的蛋白水解降解非常敏感。然而，有证据表明甲硫氨酸是该片段真正的 NH2 末端氨基酸。另一条链的分子量约为25000，NH2末端氨基酸为缬氨酸。
Activation of plasminogen was performed by perfusing a plasminogen solution through a small column loaded with insolubilized urokinase. The effluent was immediately collected in an excess of plasmin inhibitor (p-nitrophenyl-p-guanidino-benzoate). This provides a practically instantaneous inhibition of the plasmin formed and autocatalytic degradation is thus reduced to a minimum. Different degrees of activation are obtained by changing the perfusion rate.
Dodecylsulfate-polyacrylamide electrophoresis, amino acid and NH2-terminal amino acid analyses show that the activation of human plasminogen involves cleavage of at least two peptide bonds, the first event being the release of a peptide of 64 amino acid residues from the NH2-terminal end. An intermediate inactive product with a molecular weight of about 86000 and methionine as NH2-terminal amino acid is formed. Cleavage at the second site results in formation of a molecule with two chains connected by disulfide bridges. One chain which has a molecular weight of about 63000 is very sensitive to proteolytic degradation in its NH2-terminal part. However, there is evidence that methionine is the true NH2-terminal amino acid of this fragment. The other chain has a molecular weight of about 25000 and has valine as NH2-terminal amino acid.