激光引发DNA及多聚核苷酸与SO_4^-作用的闪光光谱研究

Study on Laser Flash Spectroscopy of Laser induced Interaction of DNA and Polynucleotides with SO 4 ·-

运用２４８ｎｍ激光光解瞬态吸收光谱研究了ＳＯ４·－与ＤＮＡ及其核苷酸和多聚核苷酸ｐｏｌｙ［Ｇ］、ｐｏｌｙ［Ａ］和ｐｏｌｙ［Ｃ］的相互作用，观察了各体系的作用过程，结果表明，ｐｏｌｙ［Ｇ］、ｐｏｌｙ［Ａ］与ＳＯ４·－发生单电子氧化反应生成嘌呤端基自由基；ｄＣＭＰ与ＳＯ４·－单电子氧化生成阳离子自由基，随后与水反应生成５－羟基－６Ｃ自由基；而ｐｏｌｙ［Ｃ］，ＳＯ４·－先在碱基上加成，生成的加成自由基再从核糖上抽氢生成Ｃ２’－糖自由基；ＤＮＡ与ＳＯ４·－作用生成的主要瞬态产物是鸟嘌呤端基自由基。

The interactions of DNA and polynucleotides (poly,poly and poly) with SO 4 ·- were investigated by 248 nm laser flash photolysis.The results show that,the reactions of poly or poly with SO 4 ·- yield predominantly the corresponding one electron oxidated base radicals.With poly,it is suggested that SO 4 ·- radical reacts predominantly by addition to the base moiety to produce C5 yl and C6 yl sulphate radical adducts,and subsequently H abstraction yields C2’ sugar radical.The predominant species resulting from the reaction of DNA with SO 4 ·- is DNA guanyl radical.