The recombinant plasmid was transformed into the yeast strain S. cerevisiae BJ1990 to carry out the primary expression experiment. In culture supernant of screened positive clone, the hirudin activity was detected to be 30 ATU/ml.

• 用正确的重组表达质粒转入酿酒酵母BJ1990细胞进行了初步表达实验，在筛选出的阳性克隆的培养上清中检测出的水蛭素活性为30ATU/ml，表达量达4mg/L。