摘要
凝胶电脉扫描法研究表明，γ射线辐照下，超螺旋ｐＢＲ３２２ＤＮＡ分子的残余率随剂量的增大而按指数规律减小，而辐射诱导的单链断裂（ＳＳＢ）数则与剂量线性相关。由于●ＯＨ与ＤＮＡ的反应遵循非均一动力学过程，平均引起一个ＳＳＢ所需的剂量Ｄ０随自由基清除力的增加而非线性地增大。对含一定浓度甘露醇的ＤＮＡ溶液，Ｇ（ＳＳＢ）与Ｃ（ＤＮＡ）的双倒数具有线性关系，并以二级动力学描述了ＤＮＡ和甘露醇分子对●ＯＨ的竞争反应。
With the method of gel scanning,the
residual fraction of supercoiled pBR322 DNA irradiated by 60 Co γrays was measured and
it exponentially decreased with increasing dose.At the same time,the number of SSBs per
plasmid linearly correlated with dose.Since the reaction of OH to DNA following to a
nonhomogeneous kinetics,the dose D 0 required in producing a SSB on average nonlinearly
increased with increasing scavenging capacity.Moreover,in the presence of mannitol,the
reciprocals of G(SSB) and C(DNA) had a linear relationship so that the competition reaction of
DNA and mannitol to OH radicals could be described by the second-order kinetics.In
addition,the rate coefficient and the efficiency for OH inducing SSBs were deduced.
出处
《激光生物学报》
CAS
CSCD
1999年第2期97-101,共5页
Acta Laser Biology Sinica
基金
国家自然科学基金
关键词
Γ射线
DNA单链断裂
非均一动力学
γrays
DNA single strand breaks
nonhomogeneous kinetics
rate coefficient.
