Fukui T, Ikehara M
Biochim Biophys Acta. 1979 May 24;562(3):527-33. doi: 10.1016/0005-2787(79)90115-1.
Poly(2-methyl- and 2-ethylthioadenylic acid) were prepared by polymerization of corresponding diphosphates with Escherichia coli polynucleotide phosphorylase. These polynucleotides have relatively large hypochromicity of 30-35%. Acid titration of these polymers showed abrupt transition at pH 5.34-5.4, which may indicate that the introduction of alkylthio group at 2-position of adenine bases reduced their basicity. Thermal melting of these polymers showed no clear transition points at neutral pH, but in acidic media they have Tm values of 57 and 56 degrees C, somewhat lower than that of poly(A). Upon complex formation with poly(U), these poly(A) analogs showed only one poly(rs2A) . poly(U) type double-strand complexes, similar to that found in the case of poly(m2A) . poly(U).
通过用大肠杆菌多核苷酸磷酸化酶使相应的二磷酸酯聚合制备了聚（2-甲基硫代腺苷酸和2-乙基硫代腺苷酸）。这些多核苷酸具有30-35% 的相对较大的减色效应。这些聚合物的酸滴定在pH 5.34-5.4 处显示出突然转变，这可能表明在腺嘌呤碱基的2 位引入烷硫基降低了它们的碱性。这些聚合物的热解链在中性pH 下没有明显的转变点，但在酸性介质中它们的熔点为57 和56 摄氏度，略低于聚（A）。与聚（U）形成复合物时，这些聚（A）类似物仅显示一种聚（rs2A）.聚（U）型双链复合物，类似于在聚（m2A）.聚（U）的情况中发现的复合物。
