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二价金属离子激活铜超氧化物歧化酶断裂DNA的活性

周若瑜1, 韩迎春1, 蒋伟1, 杨浩1, 刘长林2   

    1. 华中科技大学化学系, 武汉 430074;
    2. 华中师范大学农药与化学生物学教育部重点实验室, 武汉 430079
  • 收稿日期:2006-06-02 修回日期:1900-01-01 出版日期:2007-02-10 发布日期:2007-02-10
  • 通讯作者: 刘长林

Divalent Metal Ion-activated DNA Cleavage Activity of Copper Superoxide Dismutase

ZHOU Ruo-Yu1, HAN Ying-Chun1, JIANG Wei1, YANG Hao1, LIU Chang-Lin2   

    1. Department of Chemistry, Huazhong University of Science and Technology, Wuhan 430074;
    2. Key Laboratory of Pesticide & Chemical Biology, Ministry of Education, Central China Normal University, Wuhan 430079, China
  • Received:2006-06-02 Revised:1900-01-01 Online:2007-02-10 Published:2007-02-10
  • Contact: LIU Chang-Lin

摘要: 以铜超氧化物歧化酶(CunSOD, n=1—4)作为野生型CuZnSOD突变体的一种模型, 研究了其在二价金属离子(Mg2+, Mn2+)存在下由非氧化途径断裂DNA的活性, 并与CuZnSOD和脱辅基SOD(apoSOD)进行了比较. 结果表明, 在Mg2+或Mn2+存在下, CunSOD断裂DNA的活性高于CuZnSOD和apoSOD, 并且DNA的断裂活性受二价金属离子浓度、pH及酶浓度等因素影响. 相对活性及动力学参数的测定结果表明, CunSOD断裂DNA的相对能力按Cu1SOD2SOD≈Cu4SOD3SOD的顺序变化.

关键词: CuZnSOD, CunSOD, 水解, DNA断裂

Abstract: The study examined the DNA cleavage activity mediated by each member of the Cu2+-containing forms of CuZnSOD(CunSOD, n=1—4) in the presence of exogenous Mg2+ or Mn2+. The result indicates that upon addition of Mg2+ or Mn2+, CunSOD can more efficiently cleave DNA via a hydrolytic pathway compared with its holo- and apo-forms. The factors, such as exogenous divalent metal concentration, pH and enzyme concentration, can affect the DNA cleavage activity. We also measured the relative enzyme activity and the steady state kinetic parameters of the DNA cleavage reaction, indicating that the DNA cleavage activity is independent of Cu2+ number in CunSOD, and increased in an order of Cu1SOD2SOD≈Cu4SOD3SOD.

Key words: CuZnSOD, CunSOD, Hydrolysis, DNA cleavage

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