【摘要】 应用电子自旋共振(Electron spin resonance,ESR)自旋消减法,研究了内源性光敏剂2-甲基-1,4萘醌(VK3)的激发三重态(3VK3*)与核酸及其组分的反应性顺序,得到3VK3*与四个核苷及四个单核苷酸的反应性顺序为Gua>Ade>Cyt>Thy,dGMP>dAMP>dCMP>TMP。结果与早前采用激光光解瞬态吸收光谱研究3VK3*氧化DNA,测得的DNA及其组分阳离子自由基生成速率常数、核苷及核苷酸的氧化还原电位排序相一致。对3VK3*与几种富含鸟嘌呤(G)的寡聚核苷酸:端粒DNA重复序列、端粒酶RNA亚基模版及其L6-P6发夹序列反应的ESR自旋消减法研究结果表明,其反应性大小与寡聚物中鸟嘌呤含量正相关,其中与端粒DNA的反应性最强。更多还原

【Abstract】 In order to study the reaction of triplet state of VK3 with nucleic acid derivatives,the ESR(Electron spin resonance) spin elimination has been used with 4-oxo-TEMPO as spin trap.The reactivities of 3VK3* with nucleosides,nucleotides,and models of telomeric DNA,template of telomerase RNA and its L6-P6 region have been confirmed respectively.The results show that the tendency of reaction of 3VK3* with nucleosides is Gua>Ade>Cyt>Thy,meanwhile dGMP>dAMP>dCMP> TMP for reaction of 3VK3* with deoxy-nucleotides,and the one for reaction of 3VK3* with telomeric DNA is the highest in polynucleotides.This is highly accordant with both of their corresponding rate constants determined by laser flash photolysis and their oxidation-reduction potentials.It also shows that the reactivity of 3VK3* with polynucleotides is directly proportional to their G amount.更多还原