| abstract |
The invention provides an improved cardiactide recombinant expression vector pPETTRX-hk30-EK, based on which the invention also provides a preparation method of an improved cardiactide. The method comprises the steps of: converting the escherichia coli BL21 (DE3) with the improved expression vector pPETTRX-hk30-EK, culturing the converted escherichia coli BL21 (DE3), cracking the cultured escherichia coli BL21 (DE3), collecting the lysate and conducting purification through affinity chromatography so as to obtain a fusion protein; subjecting the fusion protein to enzyme digestion with an EK (enterokinase) enzyme, and carrying out gel filtration and ultrafiltration concentration to the digested product, thus obtaining the cardiactide indentical to a natural product. |