N_2O饱和水溶液体系中胸腺嘧啶的辐射交联

γ-IRRADIATED CROSSLINKING OF THYMINE IN N_2 O SATURATED AQUEOUS SOLUTION

本文研究了在N_2O饱和水溶液体系中,胸腺嘧啶的γ-辐解产物。用纸层析放射性分析法,测得胸腺嘧啶交联二聚体的产额G=2.6。用高效液相色谱放射性检测法和色谱质谱联用法,检测和鉴定胸腺嘧啶交联二聚体的结构,确定胸腺嘧啶交联二聚体是以嘧啶环上C(5)-C(5)单键连接的化合物,它们的进一步反应,形成各种不同结构的交联产物。

In this work radioactive paper chromatograph was used to separateγ-irradiated products of 2-^(14)C labelled thymine in N_2O saturated solution and the Gvalue of thymine dimers was determined to be 2.6. The preparative paper chromato-graphy was adoped to isolate thc dimers preliminary and then a high performance li-quid chromatography equiped with a radiocativity detector was applied to separateboth the preliminary isolated dimers and untreated sample. For further structure cha-racterization of dimers a capillary gas chromatography-mass spectrometry (GC-MS)was used and the mass spectra were taken from each GC separated product peak of γ-irradiated thymine in N_2O saturated solution after trimethylsilylation by BSTFA. TMSderivatives of radiation induced dimers of thymine showed the molecular ion(M^+) anda characteristic ion(M-CH_3)^+ at 718,703: 628,613; 538.523; 540, 525: These peakswere assigned to the following structures from several kinds of radical combination.such asM^+: 718(M-CH_3)^+: 703The dehydration of this dimer derives a variety of crosslinked products:TMS derivatives M^+: 718 628 538(M-CH_3)^+:703 613 528Another kind of crosslinking isTMS: M^+ 540(M-CH_3)^+ 525