High-level expression of a sika deer (Cervus nippon) Cu/Zn superoxide dismutase in Pichia pastoris and its characterization

摘要

Production of a sika deer Cu/Zn-SOD was achieved in Pichia pastoris after the reconstituted expression vector p~(PIC9K) was transformed into the strain GS115. By employing Saccharomyces cerevisiae secretion signal peptide (α-factor) under the regulation of the methanol-inducible promoter of the gene of alcohol oxidase 1 (AOX1), sika deer Cu/Zn-SOD with a molecular mass of 16 kDa was expressed while recombinant sika deer Cu/Zn-SOD with an activity of 3500 U/mL was obtained from a 5 L bioreactor. After two successive steps of chromatography on DEAE-650 C and Superdex75, recombinant sika deer Cu/Zn-SOD was obtained with 13.8% yield, 14.5-fold purification, and a specific activity of 3447 U/mg. Its optimum temperature and optimum pH were 40℃ and 7.0, respectively.