Objective: in order to provide rapid and reliable method. Methods: Encoded Annexin Ⅴ cDNA was amplifyed from U937 cDNA libary by PCR and then subcloned into E coli expression vector. MS2-Annexin Ⅴ fusion protein could be overexpressed in E coli. The MS2 bacteria protein could be removed by thrombin digestion.The mature Annexin Ⅴ was obtained by ion exchange chromatography and the FITC labled Annexin Ⅴ could be used in the detection of apoptosis. Results:Up to 37% of the total bacterial proteins was rhAnnexin Ⅴ as showed by SDS-PAGE. The purification of Annexin Ⅴ is over 99%. The FITC labled Annexin Ⅴ could efficiently detect apoptosis. Conclusion: We successfully established the technique procedure of obtaining a large quantity of Annexin Ⅴ and provided the basic routine for popularizing the detection of apoptosis' with high effciency.

The cDNA of Des(1-3)IGF1 was cloned into an fusion protein expression plasmid, pMTY4, using gene recombinant technique. The protein was purified by ion exchange chromatography and identified by SDS-polyacrylamide gel electrophoresis, radioimmunoassay(RIA), N-terminal amino acid sequence and biological activity. A prokaryotic expression vector was constructed and the fusion protein containing MS2 polymerae fragment, thrombin recognition site and human Des(1-3)IGF1 was expressed in E. coli at high level. It was showed that the purified recombinant Des(1-3)IGF1 released from the fusion protein after digestion with thrombin was identical to the native Des(1-3)IGF1.

cDNA encoding cTnI was amplified from heart muscle cDNA library by PCR and then subcloned into prokarytic vector with a thrombin linker. MS2-cTnI fusion protein was expressed in E. coli. Up to 30% of total bacterial proteins were rhcTnI as shown in SDS-PAGE gel. The rhc TnI was purified to 95% homogeneity.