ABSTRACT
Streptokinase is used clinically as an intravenous thrombolytic agent for the treatment of acute myocardial infarction and is commonly prepared from cultures of Streptococcus equisimilis strain H46A. The objective of the present study was the production of streptokinase from strain H46A and purification by chemical reduction method. The rate of streptokinase production evaluated under the effect of changes on some fermentation factors. Moreover, due to the specific structure of streptokinase, a chemical reduction method employed for the purification of streptokinase from the fermentation broth. The H46A strain of group C streptococcus, was grown in a fermentor. The proper pH adjusted with NaOH under glucose feeding in an optimum temperature. The supernatant of the fermentation product was sterilized by filtration and concentrated by ultrafiltration. The pH of the concentrate was adjusted, cooled, and precipitated by methanol. Protein solution was reduced with dithiothreitol [DTT]. Impurities settled down by aldrithiol-2 and the biological activity of supernatant containing streptokinase was determined. In the fed -batch culture, the rate of streptokinase production increased over two times as compared with the batch culture and the impurities were effectively separated from streptokinase by reduction method. Improvements in SK production are due to a decrease in lag phase period and increase in the growth rate of logarithmic phase. The methods of purification often result in unacceptable losses of streptokinase, but the chemical reduction method give high yield of streptokinase and is easy to perform it
ABSTRACT
Streptokinase has been widely prescribed as a fibrinolytic agent for myocardial infarction. Simple structural characteristics of this protein have provided techniques for production of different recombinant types of this protein. The present study was designed to prepare equisimilisH46A subtype of streptokinase in our country. Having extracted the DNA, the streptokinase gene was replicated and cloned in pGEX-4T-2. The recombinant product was transformed in BL21 [DE3] plysS'. Then the recombinant streptokinase expression and performance was assessed by lasic densitometry and special test for S2251 substrate. Use of a restriction enzyme for both sides of a gene may facilitate its cloning in different expressive carriers. Expression rate of recombinant protein [45%] confirmed successful cloning. Use of pGEX-4T-2 carrier was not only associated with active recombinant streptokinase production, added GST to its amine ending that could facilitate purification process