Study of the fibrinolytic activity of serrapeptase and its in vitro thrombolytic effects

Abstract Serrapeptase, a proteolytic enzyme, has been used for the adjuvant treatment of many diseases. However, its fibrinolytic activity is still uncertain. Herein, the fibrinolytic activity of serrapeptase and its in vitro thrombolytic effects were investigated. The results showed that the fibrinolytic activity of serrapeptase was 1295 U/mg, and the specific activity was 3867 U/mg of protein when its proteolytic activity toward casein was 2800 U/mg. The optimum temperature and pH for serrapeptase activity were 37-40°C and 9.0, respectively. At 1 mmol/L, Zn2+, Mn2+ and Fe2+ could activate the fibrinolytic activity of serrapeptase, while K+, Cu2+, sodium dodecyl sulfate (SDS) and ethylene diamine tetraacetic acid (EDTA) inhibited it. In vitro tests showed that serrapeptase could completely prevent blood coagulation at 150 U/mL, and the percentage of blood clot lysis reached 96.6% at 37°C after 4 h at 300 U/mL. These results indicate that serrapeptase has excellent fibrinolytic activity, and can be used as a health food or candidate drug for the prevention or treatment of thrombotic diseases.舍雷肽酶（Serrapeptase）是一种蛋白水解酶，已被用于多种疾病的辅助治疗。然而，其纤溶活性仍有待明确。本研究针对舍雷肽酶的纤溶活性及其体外溶栓效应展开了探究。研究结果显示，当舍雷肽酶对酪蛋白（casein）的蛋白水解活性为2800 U/mg时，其纤溶活性为1295 U/mg，比活为3867 U/mg蛋白。舍雷肽酶活性的最适温度与pH值分别为37~40℃与9.0。当浓度为1 mmol/L时，Zn²+、Mn²+与Fe²+可激活舍雷肽酶的纤溶活性，而K+、Cu²+、十二烷基硫酸钠（sodium dodecyl sulfate，SDS）与乙二胺四乙酸（ethylene diamine tetraacetic acid，EDTA）则会抑制其活性。体外实验结果表明，舍雷肽酶在150 U/mL浓度下可完全阻止血液凝固；当浓度为300 U/mL时，于37℃下孵育4 h后，血凝块溶解率可达96.6%。上述结果表明，舍雷肽酶具备优异的纤溶活性，可作为预防或治疗血栓性疾病的保健食品或候选药物。