Major P P, Egan E M, Herrick D, Kufe D W
Biochem Pharmacol. 1982 Mar 1;31(5):861-6. doi: 10.1016/0006-2952(82)90475-0.
We employed both [5-3H] ara-C and ([2-14C] ara-C labeled L1210 DNA for analysis following exposure to alkali under various conditions. The results demonstrated that the tritium label on C5 of ara-C molecules incorporated in DNA was exchanged with water under alkaline conditions and, therefore, radioactivity was subsequently detectable in the acid-soluble fraction. The [14C] ara-C labeled DNA, however, was not susceptible to loss or radioactivity by this mechanism, and the appearance of this isotope in the acid-soluble fraction required degradation of the DNA strand or pyrimidine ring. Our results indicated that the [14C] labeled DNA was degraded by alkali, suggesting structural instability of this abnormal nucleic acid. These findings provide useful technical information on the purification of (ara-C) DNA labeled with different isotopes.
我们使用[5-³H]阿糖胞苷和([2-¹⁴C]阿糖胞苷标记的L1210 DNA，在各种条件下碱处理后进行分析。结果表明，掺入DNA中的阿糖胞苷分子C5上的氚标记在碱性条件下与水发生交换，因此，随后在酸溶性部分可检测到放射性。然而，[¹⁴C]阿糖胞苷标记的DNA不会因这种机制而损失放射性，该同位素在酸溶性部分的出现需要DNA链或嘧啶环的降解。我们的结果表明，[¹⁴C]标记的DNA被碱降解，表明这种异常核酸的结构不稳定。这些发现为不同同位素标记的（阿糖胞苷）DNA的纯化提供了有用的技术信息。
