Purification and partial characterization of Cu/Zn superoxide dismutase from Kluyveromyces marxianus yeast

A new thermostable Cu/Zn SOD from a thermotolerant yeast strain Kluyveromyces marxianus NBIMCC 1984 has been purified and characterized. The purification procedure comprises thermal treatment and dialysis, ion-exchange chromatography and chromatofocusing. The methodology is a rapid, efficient and highly specific, generating pure preparation (specific activity 996 U mg of protein−1) with a yield of 53%. The purified enzyme is a homodimer with Mw of 34 034 Da and has high N-terminal homology with other yeasts’ Cu/Zn SOD enzymes. The protein is characterized with some unique features such as—thermostability (t1/2 at 70 °C = 30 min), pH stability in the alkaline range (7.5–8.5) and resistance to inhibitors and variety of chemicals. These characteristics reveal possibilities for wide practical application of K. marxianus Cu/Zn SOD enzyme.