用正常人胎肺细胞体外培养，从其培养液中分离纤溶酶原活化物（ＰＡ），通过ＣＭ－ＳｅｐｈａｄｅｘＣ－５０层析，硫酸铵沉淀和Ｆｉｂｒｉｎ－Ｓｅｐｈａｒｏｓｅ，Ｌｙｓｉｎｅ－Ｓｅｐｈａｒｏｓｅ亲和层析及ＳｅｐｈａｄｅｘＧ－５０凝胶过滤等步骤，从１０．５ｌ条件培养液中分离纯化得到两种类型的纤溶酶原活化物，ｔ－ＰＡ９０μｇ，ｕ－ＰＡ８００μｇ．在还原条件下ＳＤＳ－ＰＡＧＥ均显示单带，分子量ｔ－ＰＡ为７２ｋＤ，ｕ－ＰＡ为５４ｋＤ，纤溶比活分别为１５６０００ＩＵ／ｍｇ蛋白和１０６０００ＩＵ／ｍｇ蛋白． The normal human fetal lung cells were cultured in vitro and plasminogen activator (PA) was isolated from the culture medium. The plasminogen activator (PA) was separated by CM-Sephadex C-50 chromatography, ammonium sulfate precipitation and Fibrin-Sepharose, Lysine-Sepharose affinity chromatography SephadexG-50 gel filtration and other steps, from 10.5l conditioned medium were purified to obtain two types of plasminogen activator, t-PA90μg, u-PA800μg. Under reducing conditions SDS-PAGE showed a single band, the molecular weight of t-PA was 72kD, u-PA was 54kD, fibrinolysis specific activity were 156000IU / mg protein and 106000IU / mg protein.