【摘要】 应用吸收光谱分析法研究了交链孢酚单甲醚(Alterariol Monomethyl Ether,AME)对人胚食管DNA之间的结合作用并对结合的键型作了鉴别。研究表明,AME和DNA在37℃条件下,二者的最大吸收峰向长波方向明显位移。而且在AME和DNA结合之间存在剂量效应关系。AME和人胚食管DNA结合的最大分子比例(以AME:脱氧—磷酸核苷计)为5:1000,结合反应的平衡常数K=2.8×10~6,结合作用发生迅速而稳定。结合部位可能在碱基,无明显的碱基特异性。热变性DNA能结合更多的AME分子,说明二者的结合不需要DNA具有完整的二级结构。盐离子可严重干扰二者的结合,而脲对此则不产生明显影响,提示AME与DNA结合的主要键型为离子键而不是氢键型。AME与人胚食管DNA这种以离子键结合的方式可能在AME的诱变性/致癌性中起重要作用。更多还原

【Abstract】 The binding action between AME （alternariol monomethyl ether）and DNA of human fetal esoph-agus in vitro has been verified,and the type of binding has been identificated by means of the spectro-photometric method. The results showed that the λ_max²¹⁰ of AME and the DNA shifted toward longerwave length with decrease of absorbance peak after the incubation of AME and DNA in 37°C, andthere was a dose--dependent binding between the AME and DNA. The greatest binding ratio of AMEand DNA of the human fetal esophages was 5 AME molecules/1, 000 nucleotides. The association con-stant（K） was 2. 86×10⁶. The binding reaction occured quickly and stably. The site of binding may bein the bases,and the bindings between AME and the bases were non--specific. The heat denaturedDNA could bind more AME molecules than the natured DNA. It means that an intact secondary struc-ture of DNA molecule was not necessary for the interaction between AME and DNA. The binding wasgreatly weakened by the addition of salt was not affected by urea. These results suggest that the bindingbetween AME and DNA of human fetal esophagus might be most likely the ionic bond type rather thanthe hydrogen bond type. Maybe this type of binding plays an important role in mutagenicity/carcino-genicity of AME.更多还原