Superoxide dismutase (SOD, EC 1.15.1.1) is a member of metalloenzyme that plays a key role in protecting organisms from oxidative damage. A novel extracellular CuZn superoxide dismutase RESOD was identified from Rimicaris exoculata, a dominant species that lives in close proximity to the deep-sea hydrothermal vents. It encoded a protein consisting of 227 amino acids with a signal peptide of 22 amino acids. Sequence analysis revealed that it had the characteristics of CuZn superoxide dismutase, and had low homology with the known SODs. Then the recombinant RESOD was expressed successfully, and high-purity RESOD was obtained. The recombinant RESOD exhibited maximal activity and stability with a temperature range of 0 °C to 10 °C. And the optimal pH for the activity and stability was about 10. However, RESOD was sensitive to some metal ions, particularly calcium. Furthermore, the biological function of RESOD was investigated in HeLa cells. It was found that RESOD could reduce the level of oxidation, and decrease the apoptosis resulted from excessive oxidant challenge. In conclusion, a novel alkali-tolerant cold-active extracellular CuZn SOD was characterized. The characteristics make RESOD a good candidate in a wide range of applications.

超氧化物歧化酶（SOD，EC 1.15.1.1）是金属酶的成员，在保护生物体免受氧化损伤方面起着关键作用。从Rimicaris exoculata（一种生活在深海热液喷口附近的优势种）中鉴定出一种新型的细胞外Cu Zn超氧化物歧化酶RESOD 。它编码的蛋白质由227个氨基酸组成，信号肽为22个氨基酸。序列分析表明它具有铜的特征锌超氧化物歧化酶，与已知的SOD同源性低。成功表达了重组RESOD，获得了高纯度的RESOD。重组RESOD在0°C至10°C的温度范围内表现出最大的活性和稳定性。活性和稳定性的最佳pH约为10。但是，RESOD对某些金属离子特别是钙敏感。此外，在HeLa细胞中研究了RESOD的生物学功能。发现RESOD可以降低氧化水平，并减少由于过度的氧化剂攻击而导致的细胞凋亡。总之，表征了一种新型的耐碱冷活性细胞外铜锌超氧化物歧化酶。这些特性使RESOD在广泛的应用中成为不错的选择。