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化学学报
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化学学报 ›› 2010, Vol. 68 ›› Issue (23): 2463-2470. 上一篇    下一篇

研究论文

超氧化物歧化酶对TiO2光催化损伤DNA的影响

王晓星，顾彦，陈登霞，方艳芬，黄应平*   

  1. (三峡大学 三峡库区生态环境教育部工程研究中心 宜昌 443002)
  • 投稿日期:2010-03-27 修回日期:2010-06-18 发布日期:2010-07-06
  • 通讯作者: 黄应平 E-mail:chem_ctgu@126.com
  • 基金资助:

    国家自然科学基金项目;湖北省高校优秀中青年创新团队计划;湖北省自然科学基金创新群体项目

Effect of Superoxide Dismutase on the DNA Damage by TiO2 under UV

(Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Yichang 443002)   

  1. (Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Yichang 443002)
  • Received:2010-03-27 Revised:2010-06-18 Published:2010-07-06

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以小牛胸腺DNA为对象, 在超氧化物歧化酶(superoxide dismutase, SOD)存在下, 研究了纳米二氧化钛(TiO2)光催化对DNA损伤特性及SOD对TiO2光催化损伤DNA的影响. 采用凝胶电泳和高效液相色谱(HPLC)分析法, 探讨了DNA的损伤程度. 运用生物标准样8-羟基脱氧鸟苷(8-hydroxy-2 -deoxyguanosine, 8-OHdG)为内标物并通过高效液相色谱-电喷雾离子化串联质谱联用技术(HPLC-ESI-MS/MS)对DNA损伤产物进行了跟踪分析, 采用过氧化物酶催化分光光度法及顺磁共振技术(ESR)跟踪测定TiO2光催化DNA损伤过程中H2O2和氧化物种的变化, 探讨了DNA氧化损伤机理. 结果表明, 在实验条件下紫外光照(UV, λ＝200～275 nm), Dark/TiO2和UV/TiO2体系中, DNA氧化损伤程度为UV/TiO2＞UV＞Dark/TiO2. 光催化260 min DNA损伤99%, 反应动力学常数K＝7.82×10－3 min－1. 抗氧化剂SOD具有清除光催化体系中超氧自由基( )的能力, 可以抑制DNA的损伤, 反应动力学常数K＝2.27×10－3 min－1. 8-OHdG为DNA损伤中鸟嘌呤氧化的特异产物, UV及光催化体系对DNA损伤主要涉及 及羟基自由基(•OH)历程, 光催化体系对DNA损伤伴随有深度氧化(矿化)过程, 实验条件下12 h DNA矿化75.06%.

关键词: 小牛胸腺DNA, DNA损伤, 光催化, 超氧化物歧化酶

DNA damage in the photocatalysis system of TiO2 and the effect of SOD were studied using calf thymus DNA as research object. The degree of DNA damage was detected by gel electrophoresis and high performance liquid chromatography (HPLC) analysis. 8-Hydroxy-2 -deoxyguanosine (8-OHdG) was used as an internal standard, HPLC-ESI-MS/MS were employed to analyze products of DNA damage. Peroxidase catalytic spectrophotometry and electron spin resonance (ESR) were used to determine the content of H2O2 and the change of reactive oxygen species, the mechanism of DNA damage was studied. The results indicated that the degree of DNA damage in different systems was in the order of UV/TiO2＞UV＞Dark/TiO2, the degree of DNA damage reached 99% after 260 min and the reaction kinetic constants K was equal to 7.82×10－3 min－1. SOD used as an antioxidant had the ability of removing free radicals and inhibiting DNA damage, the reaction kinetic constants K was equal to 2.27×10－3 min－1 in the system with SOD. 8-OHdG was the special product of guanine damage. DNA damage process was predominated mainly by the hydroxyl radical (•OH) and superoxide radical ( ) generated in the system. Besides, photocatalytic damage was with the mineralization of DNA and mineralization rate reached 75.06% after 12 h.

Key words: calf thymus DNA, DNA damage, photocatalysis, superoxide dismutase