Then bacteria were collected by centrifugation and split by ultrasonic method . the purified products were analyzed by tris - tricine sds - page . the immuno - activity of the recombinant proteins were analyzed by western blot 将离心收集到的菌体超声破壁,离心分离,收集上清液,进行离子交换层析和分子筛分离纯化。