[Objective]To construct optimized human cystatin c expression system,and obtain a soluble,stable and high purity recombinant cystatin C.[Methods]The optimized human cystatin C gene was synthesized and cloned into pRSF-Duet vector with MBP residue to generate p MBP-CYSC PRSF expression vector. Recombinant human cystatin C protein was expressed in E. coli BL21( DE3) p Lys S,the protein purity and molecular weight were identified by SDS-PAGE,the concentration of the purified human cystatin C was analyzed by hi...