Brown H S, Shapiro R
Biochim Biophys Acta. 1977 Mar 18;475(2):241-53. doi: 10.1016/0005-2787(77)90015-6.
The following procedures have been used to prepare fifteen modified dinucleoside monophosphates: (a) bisulfite-catalyzed transamination with aniline to give an N4-phenylcytidine (CPh), (b) bisulfite-catalyzed transamination with beta-naphthylamine to give an N4-beta-naphthylcytidine (CbetaN), (c) alkylation with 7-bromomethylbenz[a] anthracene to afford a 7(benz[a]anthryl-7-methyl)guanosine (GMBA), and (d) reaction with N-acetoxy-2-acetylaminofluorene to give an 8-(N-2-fluorenylacetamido)guanosine (GAAF). The compounds prepared were A-CPh, CPh-A, CPh-G, U-CPh, CPh-U, A-CbetaN, CbetaN-A, G-CbetaN, CbetaN-G, U-CbetaN, CbetaN-U, GMBA-U, U-GMBA, GAAF-U, and U-GAAF. All of the modified compounds were hydrolyzed to the expected monomers with venom and spleen exonucleases. Hydrolysis by micrococcal nuclease was inhibited in the following cases: A-CPh, A-CbetaN, U-GMBA, and U-GAAF. The first three reactions above were applied to denatured calf thymus DNA to prepare modified DNA samples containing from 0.3 to 2.0% bound aromatic residues. The modified nucleic acids were completely hydrolyzed to nucleosides by the combination of venom exonuclease, deoxyribonuclease I and alkaline phosphatase. The same results were obtained with a combination of spleen exonuclease, deoxyribonuclease II, and alkaline phosphatase. Hydrolysis of the modified nucleic acids by micrococcal nuclease and alkaline phosphatase afforded primarily nucleosides, with some dinucleoside monophosphates. The amount of the latter did not exceed that found in the hydrolysis of control DNA, however. Other workers have observed inhibition of enzymatic hydrolysis of nucleic acids modified by aromatic carcinogens. We postulated that their results may have been caused by cross-links, which were avoided in our studies.
已采用以下步骤制备了15种修饰的单磷酸二核苷：(a) 用亚硫酸氢盐催化与苯胺进行转氨反应，得到N4-苯基胞苷（CPh）；(b) 用亚硫酸氢盐催化与β-萘胺进行转氨反应，得到N4-β-萘基胞苷（CβN）；(c) 用7-溴甲基苯并[a]蒽进行烷基化反应，得到7-(苯并[a]蒽基-7-甲基)鸟苷（GMBA）；(d) 与N-乙酰氧基-2-乙酰氨基芴反应，得到8-(N-2-芴基乙酰氨基)鸟苷（GAAF）。所制备的化合物有A-CPh、CPh-A、CPh-G、U-CPh、CPh-U、A-CβN、CβN-A、G-CβN、CβN-G、U-CβN、CβN-U、GMBA-U、U-GMBA、GAAF-U和U-GAAF。所有修饰化合物都能被蛇毒和脾外切核酸酶水解为预期的单体。在以下情况下，微球菌核酸酶的水解受到抑制：A-CPh、A-CβN、U-GMBA和U-GAAF。上述前三个反应应用于变性的小牛胸腺DNA，以制备含有0.3%至2.0%结合芳香族残基的修饰DNA样品。修饰的核酸通过蛇毒外切核酸酶、脱氧核糖核酸酶I和碱性磷酸酶的组合完全水解为核苷。用脾外切核酸酶、脱氧核糖核酸酶II和碱性磷酸酶的组合也得到了相同的结果。微球菌核酸酶和碱性磷酸酶对修饰核酸的水解主要产生核苷，还有一些单磷酸二核苷。然而，后者的量不超过对照DNA水解中发现的量。其他研究人员观察到芳香族致癌物修饰的核酸酶促水解受到抑制。我们推测他们的结果可能是由交联引起的，而我们的研究中避免了这种情况。
