Bacillus licheniformis HJ4 showing strong fibrinolytic activity was isolated from Hwangseokae jeotgal. aprEHJ4, a major fibrinolytic gene, was cloned by PCR, and an ORF consisting of 379 amino acids was located. The mature enzyme was expected to be 27 kDa in size after processing, but a 24-kDa protein was observed by SDS-PAGE and fibrin zymography, indicating additional processing. RT-qPCR showed that expression level of aprEHJ4 in culture with 0% salt (control) was the highest followed by culture with 8% salt (89.7% of control) and 5% salt (74.2%) at 84 h. The expression level in culture with 15% salt was 46.9%. The results matched with the fibrinolytic activity measurements of cultures and indicated that AprEHJ4 maintained significant activity in the presence of salt up to 15% (w/v). AprEHJ4 was overproduced in Escherichia coli, and mature 27 kDa protein was purified after in vitro renaturation. The optimum pH and temperature of AprEHJ4 were pH 8 and 40 ℃, respectively.

从Hwangseokae jeotgal中分离出具有强纤溶活性的地衣芽孢杆菌HJ4。通过PCR克隆了主要纤溶基因aprEHJ4 ，并定位了由379个氨基酸组成的ORF。处理后成熟酶的大小预计为 27 kDa，但通过 SDS-PAGE 和纤维蛋白酶谱观察到 24 kDa 的蛋白质，表明进行了额外的处理。 RT-qPCR显示，84 h时，0%盐培养物（对照）中aprEHJ4的表达水平最高，其次是8%盐培养物（对照的89.7%）和5%盐培养物（74.2%）。 15%盐培养物中的表达水平为46.9%。结果与培养物的纤溶活性测量值相匹配，表明 AprEHJ4 在高达 15% (w/v) 的盐存在下仍保持显着的活性。 AprEHJ4在大肠杆菌中过量产生，体外复性后纯化出成熟的27 kDa蛋白。 AprEHJ4的最适pH和温度分别为pH 8和40℃。