<正>ASPNJ(Acidic Serine Protease from Neanthes japonica)was first isolated and purified from Neanthes japonica in our lab.ASPNJ has both strong plasmin and proteolytic enzyme activities.The effects of ASPNJ on leukemia Jurkat cell were determined in order to provide an innovation direction for research and treatment of leukemia.1.ASPNJ has much strong