Doskocil J, Holý A, Filip J
Nucleic Acids Res. 1974 Oct;1(10):1209-20. doi: 10.1093/nar/1.10.1209.
Intact cells and cell-free extracts of E. coli convert isocytidine to isocytosine and uracil. The radioactive label of 5-[(3)H]isocytidine is incorporated into RNA and, DNA of growing bacteria at a rate equal to about 1.4% of that of cytidine under similar conditions; the radioactivity is found in uridylic, cytidylic and 2'-deoxythymidylic acids, while less than 0.4% of incorporated radioactive material might be due to possible incorporation of intact isocytidine. Uridine phosphorylase and cytidine deaminase apparently do not participate in the metabolic conversion of isocytidine.5-[(3)H]isocytidine was prepared by platinum-catalyzed dehalogenation of 5-bromoisocytidine in the presence of tritium. The 5-bromo derivative was obtained from 2',3'-0- -isopropylideneisocytidine by N-bromsuccinimide bromination followed by acidic hydrolysis.
大肠杆菌的完整细胞和无细胞提取物可将异胞苷转化为异胞嘧啶和尿嘧啶。在类似条件下，5-[(3)H]异胞苷的放射性标记以约胞苷1.4%的速率掺入生长细菌的RNA和DNA中；放射性存在于尿苷酸、胞苷酸和2'-脱氧胸苷酸中，而掺入的放射性物质中不到0.4%可能是由于完整异胞苷的可能掺入。尿苷磷酸化酶和胞苷脱氨酶显然不参与异胞苷的代谢转化。5-[(3)H]异胞苷是通过在氚存在下铂催化5-溴异胞苷的脱卤反应制备的。5-溴衍生物是由2',3'-O-异丙叉基异胞苷经N-溴代琥珀酰亚胺溴化，然后酸性水解得到的。
