Peterson D M, Moore E C
Biochim Biophys Acta. 1976 Apr 15;432(1):80-91. doi: 10.1016/0005-2787(76)90043-5.
The activities of CDP and ADP reductases were determined throughout the cell cycle of Chinese hamster fibroblasts synchronized by partial deprivation of isoleucine. Both enzyme activities were increased in S phase as compared to G1 phase. CDP reductase increased about 8-fold while ADP reductase increased about 2.5-fold. The ratio of CDP to ADP reductase was 0.26 at the G1 and early S phases of the cell cycle; the ratio was increased to 0.83 by late S phase. Addition of actinomycin D or cycloheximide to cell cultures in G1 phase prevented the increase of both CDP and ADP reductases activities in the latter part of the cell cycle, but the ratio of the two activities was not affected. The ratio of CDP to ADP reductase activities varied from 0.8 to 3 in different populations of exponentially growing DON cells. These results show that CDP and ADP reductase activities vary independently in growing cells. The independent variation with cell growth of CDP and ADP reductases suggests important individual functions of the deoxynucleotides during the cell cycle apart from their common role as precursors of DNA synthesis.
通过部分剥夺异亮氨酸使中国仓鼠成纤维细胞同步化，在整个细胞周期中测定了CDP还原酶和ADP还原酶的活性。与G1期相比，S期两种酶的活性均增加。CDP还原酶增加了约8倍，而ADP还原酶增加了约2.5倍。在细胞周期的G1期和S期早期，CDP与ADP还原酶的比率为0.26；到S期后期，该比率增加到0.83。在G1期向细胞培养物中添加放线菌素D或环己酰亚胺可阻止细胞周期后期CDP和ADP还原酶活性的增加，但两种活性的比率不受影响。在指数生长的DON细胞的不同群体中，CDP与ADP还原酶活性的比率在0.8至3之间变化。这些结果表明，在生长的细胞中CDP和ADP还原酶活性独立变化。CDP和ADP还原酶随细胞生长的独立变化表明，除了作为DNA合成前体的共同作用外，脱氧核苷酸在细胞周期中还具有重要的个体功能。
