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 degrees C to 60 degrees C at an optimal temperature of 20 degrees C and 30 degrees 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 beta-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. (C) 2019 Published by Elsevier B.V.