title: A highly stable Cu/Zn superoxide dismutase from Withania somnifera plant: gene cloning, expression and characterization of the recombinant protein.
abstract: A gene from Withania somnifera (winter cherry), encoding a highly stable chloroplastic Cu/Zn superoxide dismutase (SOD), was cloned and expressed in Escherichia coli. The recombinant enzyme (specific activity of ~4,200 U mg(-1)) was purified and characterized. It retained ~90 and ~70% residual activities after 1 h at 80 and 95 °C, respectively. At 95 °C, thermal inactivation rate constant (K (d)) of the enzyme was 2.46 × 10(-3) min(-1) and half-life of heat inactivation was 4.68 h. The enzyme was stable against a broad pH range (2.5-11.0). It also showed a high degree of resistance to detergent, ethanol and protease digestion. This recombinant Cu/Zn SOD could therefore have useful applications.
authors.affiliation: National Botanical Research Institute, Council of Scientific and Industrial Research, Rana Pratap Marg, Lucknow, UP 226001, India. raju_mdnl@rediffmail.com
authors.forename: Raju
authors.initials: R
authors.lastname: Madanala
authors.forename: Vijayta
authors.initials: V
authors.lastname: Gupta
authors.forename: Farah
authors.initials: F
authors.lastname: Deeba
authors.forename: Santosh Kumar
authors.initials: SK
authors.lastname: Upadhyay
authors.forename: Vivek
authors.initials: V
authors.lastname: Pandey
authors.forename: Pradhyumna Kumar
authors.initials: PK
authors.lastname: Singh
authors.forename: Rakesh
authors.initials: R
authors.lastname: Tuli
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004591:Electrophoresis, Polyacrylamide Gel; D004795:Enzyme Stability; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D013482:Superoxide Dismutase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D032341:Withania / Q000201:enzymology* / Q000235:genetics
chemical_list: D011994:Recombinant Proteins; D013482:Superoxide Dismutase