美国Genentech公司已开发一种组织纤溶酶原激活剂（TPA）突变体,它具有原重组TPA的所有优点,但没有其缺点。 TPA通过与纤维蛋白结合而溶解血凝块。纤维蛋白仅见于血凝块中,是引起血小板聚集的少数蛋白之一,TPA是很好的血栓溶解剂,它仅消散血凝块,但对正常血液无作用。然而,大剂量TPA可引起过度出血,TPA的主要缺点是半衰期很短,所以必须缓慢输注,以保证在血循环中有少量活性蛋白。目前研制的所有TPA突变体半衰期较长,但对纤维蛋白特异性较差。 Genentech公司拟开发一种对纤维蛋白特异性较强、从血液中清除较慢和对纤溶 Genentech, Inc. of the United States has developed a tissue plasminogen activator (TPA) mutant that has all the advantages of the original recombinant TPA but without its disadvantages. TPA dissolves blood clots by binding to fibrin. Fibrin is found only in blood clots and is one of the few proteins that cause platelet aggregation. TPA is a good thrombolytic agent that dissipates blood clots but has no effect on normal blood. However, high doses of TPA can cause excessive bleeding, the main disadvantage of TPA is the short half-life, it must be slow infusion to ensure that there is a small amount of active protein in the blood circulation. All TPA mutants developed at present have a longer half-life but poor specificity for fibrin. Genentech intends to develop a stronger specificity for fibrin, slower clearance from the blood and fibrinolysis