Mechanism of oxidative damage to DNA by Fe-loaded MCM-41 irradiated with visible light  

作　　者：WANG XiaoXing GU Yan FANG YanFen HUANG YingPing 

机构地区：[1]Engineering Research Center of Eco-environment in Three Gorges Reservoir Region,Ministry of Education,China Three Gorges University,Yichang 443002,China

出　　处：《Chinese Science Bulletin》2012年第13期1504-1509,共6页

基　　金：supported by the National Natural Science Foundation of China (20877048, and 21177072);the National Basic Research Program of China (2008CB417206);the Innovation Group Project of Hubei Province Natural Science Foundation(2009CDA020, and T200703)

摘　　要：The mechanism of oxidative damage to deoxyribonucleic acid (DNA) by iron-containing mesoporous molecular sieves (MCM-41) irradiated with visible light was elucidated. Fe-loaded MCM-41 (Fe/MCM-41) was used as a photocatalyst and the damage to calf thymus DNA caused by hydrogen peroxide (H2O2) was studied. The damage and extent of oxidation of DNA were measured by high-performance liquid chromatography (HPLC) and intermediate products were detected by HPLC/electrospray ionization tandem mass spectrometry. Electron spin resonance was used to detect changes in reactive oxygen species and peroxidase catalytic spectrophotometry was used to determine the concentration of H2O2. The results indicated that Fe/MCM-41 efficiently activated H2O2 in solution at pH 4.0-8.0 under irradiation with visible light. The photocatalytic system degraded DNA most effectively at pH 5.0-6.0 but also operated at pH 8.0. At pH 4.2, the degree of DNA damage reached 25.65% after 5 h and the kinetic constant was 5.89×10 2 min 1. Damage to DNA was predominantly caused by hydroxyl radicals generated in the system. The mechanism of DNA damage is of potential concern to human health because it can occur in neutral solutions irradiated by visible light.The mechanism of oxidative damage to deoxyribonucleic acid （DNA） by iron-containing mesoporous molecular sieves （MCM-41） irradiated with visible light was elucidated. Fe-loaded MCM-41 （Fe/MCM-41） was used as a photocatalyst and the damage to calf thymus DNA caused by hydrogen peroxide （H202） was studied. The damage and extent of oxidation of DNA were measured by high-performance liquid chromatography （HPLC） and intermediate products were detected by HPLC/electrospray ionization tan- dem mass spectrometry. Electron spin resonance was used to detect changes in reactive oxygen species and peroxidase catalytic spectrophotometry was used to determine the concentration of H202. The results indicated that Fe/MCM-41 efficiently activated H202 in solution at pH 4.0-8.0 under irradiation with visible light. The photocatalytic system degraded DNA most effectively at pH 5.0-6.0 but also operated at pH 8.0. At pH 4.2, the degree of DNA damage reached 25.65% after 5 h and the kinetic constant was 5.89x10-2 min-1. Damage to DNA was predominantly caused by hydroxyl radicals generated in the system. The mechanism of DNA damage is of potential concern to human health because it can occur in neutral solutions irradiated by visible light.

关 键 词：DNA氧化损伤 MCM-41 可见光照射 含铁 机制 过氧化氢溶液 高效液相色谱 DNA损伤 

分 类 号：Q523[生物学—生物化学] TQ424.25[化学工程]