Abstract: The total RNA of human liver was extracted and human Mn-SOD gene was amplified by RT-PCR. Manganese SOD gene was expressed in P. pastoris after construction of expression vector. The optimized gene codon, which is based on yeast major preference codons was also expressed in P. pastoris. Meanwhile, enzyme-producing ablilities of the two genetic engineering strains were compared. Results showed that the optimized strain have advantage on ability of producing enzyme over the control. It can be concluded that optimization of gene sequence plays an important role in its expression.

Key words: superoxide dismutase, Pichia pastoris, optimization, expression