Progress in dynamic study on the triplet excited states and radical ions of DNA and its components

Progress in dynamic study on the triplet excited states and radical ions of DNA and its components is reviewed. It has been found that acetone is the only effective sensitizer for the study of the triplet excited states of DNA components. The transient absorption spectrum of guanyl radical cation resulting from the interaction of triplet acetone and DNA was observed directly, and the original evidence for selective damage of DNA by excited photosensitizer was obtained for the first time, which offered a new pathway for obtaining the main transient species of selective damage of DNA by photonucleases and illustrating initial oxidation mechanism of DNA via electron transfer.     

核黄素光敏损伤端粒DNA单链及端粒酶RNA亚基机理研究

采用电子自旋共振（ESR）消减法及光切割法对核黄素激发三重态单电子氧化寡聚核苷酸的机理进行了探讨．结果表明：UVA光照下,作为内源性光敏剂的核黄素能够高效切割端粒DNA单链及端粒酶RNA亚基用于合成端粒DNA的模版区,从根本上阻断端粒酶维持癌细胞端粒DNA长度的反转录过程,促使癌细胞凋亡．     

对-甲基杯[4]芳烃激光光解的研究

研究了对－甲基杯[4]芳烃在环己烷和乙腈中的激光光解行为,在环己烷中观察到４２００nm及５４０nm附近的杯芳烃激发三线态吸收峰,极性溶剂乙腈对该三核态有稳定作用,吸收峰显著红移,其三线态双峰特征与不带取取代基的杯[4]芳烃相近,同时发现在３３０nm附近杯芳烃自由基吸收峰,其动力学分析表明,该自由基按二级动力学衰减。     

芳香氨基酸光电离过程的pH效应

运用248nm激光闪光光解瞬态吸收光谱研究了不同pH值水溶液中芳香氨基酸的光电离过程。结果表明,pH值对酪氨酸和色氨酸的光电离过程有显著影响：溶液的pH值增大,光电离倾向于单光子过程,pH减小倾向于双光子过程;而对苯丙氨酸几乎没有影响．酪氨酸、色氨酸光电离过程的pH效应分别源于酚羟基氢、吲哚环上>NH的解离．解释了国外学者在水合电子量子产额测定结果上的不一致现象。