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Updated: Dec 15, 2025
Overexpressing and Purifying a Toxic Nuclease from Escherichia coli
Published on: August 29, 2025
High-level soluble expression of human Cu,Zn superoxide dismutase with high activity in Escherichia coli
Jin-Ling Yang1, Xing-Lun Li2, Feng-Lin Jiang2
1State Key Laboratory of Bioactive Substance and Function of Natural Medicines, NHC Key Laboratory of Biosynthesis of Natural Products, CAMS Key Laboratory of Enzyme and Catalysis of Natural Drugs, Institute of Materia Medica, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, 100050, China. yangjl@imm.ac.cn.
Abstract:
As the most important member of antioxidant defense system, human Cu,Zn superoxide dismutase (hCu,Zn-SOD) protects cells against the free radicals produced by aerobic metabolism. hCu,Zn-SOD has been widely used in food, cosmetic and medicine industry due to its health benefits and therapeutic potentials. However, a more extensive application of hCu,Zn-SOD is limited by the challenge of expensive and low production of high-activity hCu,Zn-SOD in large scale. In this study, the codon-optimized hCu,Zn-SOD gene was synthesized, cloned into pET-28a( +) and transformed into Escherichia coli BL21(DE3). After induction with IPTG or lactose, hCu,Zn-SOD was highly expressed as soluble form in LB medium with 800 μM Cu2+ and 20 μM Zn2+ at 25 °C. The recombinant hCu,Zn-SOD was efficiently purified by nickel affinity chromatography. Through optimization of fed-batch fermentation conditions, 342 mg purified hCu,Zn-SOD was obtained from 1 L cultures fermented in a 3-L bioreactor. Furthermore, the recombinant hCu,Zn-SOD retained the enzymatic specific activity of 46,541 U/mg. This study has opened up an effective avenue for industrial production of hCu,Zn-SOD through microbial fermentation in the future.
