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BioMed Research International
Volume 2014, Article ID 324705, 9 pages
Research Article

Highly Effective Renaturation of a Streptokinase from Streptococcus pyogenes DT7 as Inclusion Bodies Overexpressed in Escherichia coli

1Institute of Biotechnology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet Road, District of Cau Giay, Hanoi 10600, Vietnam
2Department of Biotechnology and Pharmacology, University of Science and Technology of Hanoi, 18 Hoang Quoc Viet Road, District of Cau Giay, Hanoi 10600, Vietnam

Received 12 November 2013; Revised 28 February 2014; Accepted 31 March 2014; Published 5 May 2014

Academic Editor: Noomen Hmidet

Copyright © 2014 Sy Le Thanh Nguyen et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The streptokinase (SK) is emerging as an important thrombolytic therapy agent in the treatment of patients suffering from cardiovascular diseases. We reported highly effective renaturation of a SK from S. pyogeness DT7 overexpressed in E. coli, purification, and biochemical characterization. A gene coding for the SK was cloned from S. pyogeness DT7. Because accumulation of active SK is toxic to the host cells, we have expressed it in the form of inclusion bodies. The mature protein was overexpressed in E. coli BL21 DE3/pESK under the control of the strong promoter tac induced by IPTG with a level of 60% of the total cell proteins. The activity of the rSK, renatured in phosphate buffer supplemented with Triton X-100 and glycerol, was covered with up to 41 folds of its initial activity. The purified of protein was identified with MALDI-TOF mass spectrometry through four peptide fragments, which showed 100% identification to the corresponding peptides of the putative SK from GenBank. Due to overexpression and highly effective renaturation of large amounts of inclusion bodies, the recombinant E. coli BL21 DE3/pESK system could be potentially applied for large-scale production of SK used in the therapy of acute myocardial infarction.