Abstract: A 76mer seleniumcontaining peptide (SeCuZn76P) with double glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity, which was embedded in a sequence of membranepenetrating domain, was designed according to the principles of module enzyme, and was expressed by the method of cysteine auxotrophic expression in a single protein production (SPP) system, then the cellpenetrating effects of Se-CuZn-76P were identified. Experimental results show that the method can successfully express the high purity of SeCuZn76P, and demonstrate GPx activity (109 μmol/min) and SOD activity (1 218 μmol/min) per mg of protein. The GPx activity and the SOD activity in hepatic L02 cells are increased by 1.65 and 4.12 times respectively, when L02 cells are cultured for a period of time in the presence of SeCuZn76P, and SeCuZn76P can be successfully entered into L02 cells.

Key words: superoxide dismutase, cell penetrating peptide, single protein production system, glutathione peroxidase, cysteine auxotrophic expression, selenium