蚯蚓体内一种纤溶酶原激活剂(e-PA)的分离纯化

为获得一种高效，低廉的溶栓药物，从赤子爱胜蚓（Ｅｉｓｅｎｉａｆａｅｔｉｄａ）体内分离纯化出一种可体外激活纤溶酶原从而间接降解纤维蛋白的酶（ｅ－ＰＡ）．纯化过程包括：粗品的盐析，离子交换层析，凝胶过滤层析及疏水相互作用层析．该组份是由二个亚基通过疏水相互作用维系在一起的．通过凝胶过滤层析，可测得全酶的分子量为４５０００；ＳＤＳ电泳显示大、小亚基的分子量分别是２６０００与１８０００；而质谱法测得的大、小亚基的分子量分别为２４５５６．７与１５５４６．６．对大小亚基进行了氨基酸组成分析，结果显示大亚基不含Ｌｙｓ而小亚基不含Ｃｙｓ．测定了大亚基Ｎ端２５个氨基酸序列：ＶＩＧＧＴＮＡＳＰＧＥＩＰＷＱＬＳＱＱＲＱＳＧＳＷ．并与部分已知蛋白质序列进行了比较．ｅ－ＰＡ在纤维蛋白平板上表现有三种不同的纤溶活性

Purification of a Plasminogen Activator from Eisenia faetida

To obtain a more effective drug for thrombolysis,a novel plasminogen activator was purified from Eisenia faetida .The procedure included DEAE Sepharose Fast Flow column,Sephadex G 75 column and Phenyl Sepharose 4 fast Flow (low substitute)column chromatography in order.The enzyme was composed of two kinds of subunits (L,large;S,small)which were held together by hydrophobic interactions.In gel filtration,the molecular weight of intact enzyme was 45 000.According to SDS PAGE,the molecular weights of L and S were 26 000 and 18 000 respectively,while determined by MS(mass spectrum),the molecular weights of L and S were 24 556.7 and 15 546.6 respectively.There was no Cys in the S subunit and Lys in the L subunit.The N terminal sequence of L was analyzed,which was VIGGTNASPGEIPWQLSQQRQSGSW,and was compared with some known proteins.It was serine proteases that shared higher similarities between the 25 amino acids sequence.The enzyme showed three different kinds of fibrinolytic activities on fibrin plate,which were designated as CFPg(complete fibrinolysis with plasminogen),uCFPg(uncompleted fibrinolysis with plasminogen)and uCF(uncompleted fibrinolysis without plasminogen).