A novel, kinetically stable copper, zinc superoxide dismutase from Psychropotes longicauda.

Superoxide dismutases (SODs) are one of the most important antioxidant enzymes against oxidative damage. In the present study, we cloned and expressed a novel and stable Cu, Zn-SOD from a hadal sea cucumber Psychropotes longicauda (i.e., Pl-Cu, Zn-SOD). The purified recombinant enzyme was intracellular, dimeric with the Mr. of approximately 38 kDa, with the expressed activity from 0 °C to 60 °C at an optimal temperature of 20 °C and 30 °C and maximum activity at the pH of 8.0. The Km and Vmax values of Pl-Cu, Zn-SOD were 0.041 ± 0.004 mM and 1450.275 ± 36.621 U/mg, respectively. At tested conditions, Pl-Cu, Zn-SOD was relatively stable in chemicals, such as β-ME, EDTA, Tween 20, Triton X-100, and Chaps, especially in urea and guanidine hydrochloride, which can resist protease hydrolysis and tolerate high hydrostatic pressure of 100 MPa and 2 M NaCl. All these properties make Pl-Cu, Zn-SOD a candidate in the biopharmaceutical and nutraceutical fields, and help us better understand the adaptation mechanism of hadal area.