Cloning and expression of native streptokinase in E. coli BL21(DE3)

Abstract

Streptokinase (SK) is a potent plasminogen activator naturally produced by beta-hemolytic streptococcus bacteria. Streptokinase is one of the most important thrombolytic agents that was frequently employed treatment of myocardial infarction. In this study, we amplified the SK gene isolated from Streptococcus pyogenes. The sequence of SK was recorded in the NCBI database. The Accession number of the SK sequence was LC625519.1. The SK gene was digested by EcoR1 and Hindlll, ligated with the linear pGEM®-3Zf (+) vector, and then introduced into an expression host E. coli BL21(DE3). For the production of the SK protein, we induced by 1mM IPTG. SDS-PAGE was used for the evaluation of the streptokinase synthesis with a molecular weight of around 47 kDa. Using the casein lysis method and the in vitro clot lysis assay, the activity of native SK was assessed. The native SK has clot lysis activity and a clear zone in the casein plate.