Darzynkiewicz E, Labadi I, Haber D, Burger K, Lönnberg H
Department of Biophysics, University of Warsaw, Poland.
Acta Chem Scand B. 1988 Feb;42(2):86-92. doi: 10.3891/acta.chem.scand.42b-0086.
First-order rate constants for the alkaline opening of the imidazole ring of several 7-methylguanine nucleotides and their structural analogues were determined. The results obtained suggested that intramolecular interaction between the negatively charged 5'-phosphate group and the positively charged imidazole ring markedly retard the attack of hydroxide ion on the C8 atom of the 7-methylguanine ring. In contrast, hardly any influence on the acidities of the interacting base and phosphate moieties was detectable. No effect on the complexing of the phosphate group with magnesium(II) ion could be detected.
测定了几种7-甲基鸟嘌呤核苷酸及其结构类似物咪唑环碱性开环的一级速率常数。所得结果表明，带负电荷的5'-磷酸基团与带正电荷的咪唑环之间的分子内相互作用显著阻碍了氢氧根离子对7-甲基鸟嘌呤环C8原子的进攻。相比之下，几乎检测不到对相互作用的碱基和磷酸部分酸度的任何影响。未检测到对磷酸基团与镁（II）离子络合的影响。
