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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。
Absorption spectroscopy was used to study the binding effect of Alterariol Monomethyl Ether (AME) on the DNA of human embryo esophagus and to identify the bond type. The results showed that the maximum absorption peak of both AME and DNA shifted to the longwave direction at 37 ℃. There is also a dose-response relationship between AME and DNA binding. The maximum molecular ratio of AME binding to human embryo esophageal DNA (AME: deoxy-nucleoside) is 5: 1000, and the equilibrium constant of the binding reaction is K = 2.8 × 10 ~ 6. The binding effect is rapid and stable. The binding site may be at the base, with no apparent base specificity. Thermal denatured DNA can bind more AME molecules, indicating that the combination of the two does not require the DNA to have a complete secondary structure. Salt ions can seriously interfere with the combination of the two, but urea did not have a significant impact on this, suggesting that AME and DNA binding the main bond type for ionic rather than hydrogen-bonding. The ionic bond between AME and human embryo esophageal DNA may play an important role in the mutagenicity / carcinogenesis of AME.