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本文从低分子量尿激酶(LUK)中分离并纯化了UK 135—157片段,用放射结合分析证明UK 135—157片段和纤维蛋白对tPA的结合呈竞争关系。用酪蛋白降解系统证明此片段可抑制纤维蛋白促进tPA对纤溶酶原的激活。化学合成了UK149—157九肽(R-肽)以及由Asp取代Arg 154和Arg 156的相应九肽(D-肽),发现R-肽对纤维蛋白促进tPA激活纤溶酶原有显著的抑制作用,而D-肽却全无作用。本文结果证明:UK 149—157片段中的正电荷残基在抑制环饼结构域的纤维蛋白结合活性中起重要作用。
In this paper, UK 135-157 fragment was isolated and purified from low molecular weight urokinase (LUK). Radiobag analysis was used to demonstrate that UK 135-157 fragment and fibrin compete with tPA binding. This casein degradation system was used to demonstrate that this fragment inhibits fibrin from promoting plasminogen activation by tPA. The UK 149-157 nonapeptide (R-peptide) and the corresponding nonapeptide (D-peptide) substituted with Asp for Arg 154 and Arg 156 were chemically synthesized and found to have a significant inhibitory effect of fibrin on tPA-activated plasminogen Role, while the D-peptide has no effect. Our results demonstrate that the positively charged residues in the UK 149-157 fragment play an important role in inhibiting the fibrin binding activity of the circular ciliate domain.