Wortmann R L, Mitchell B S, Edwards N L, Fox I H
Proc Natl Acad Sci U S A. 1979 May;76(5):2434-7. doi: 10.1073/pnas.76.5.2434.
Deoxyadenosine metabolism was investigated in cultured human cells to elucidate the biochemical basis for the sensitivity of T lymphoblasts and the resistance of B lymphoblasts to deoxyadenosine toxicity. T lymphoblasts have a 20-to 45-fold greater capacity to synthesize deoxyadenosine nucleotides than B lymphoblasts at deoxyadenosine concentrations of 50--300 micron. During the synthesis of dATP, T lymphoblasts accumulate large quantities of dADP, whereas B lymphoblasts do not accumulate dADP. Enzymes affecting deoxyadenosine nucleotide synthesis were assayed in these cells. No substantial differences were evident in activities of deoxyadenosine kinase (ATP: deoxyadenosine 5'-phosphotransferase, EC 2.7.1.76) or deoxyadenylate kinase [ATP:(d)AMP phosphotransferase, EC 2.7.4.11]. The activity of 5'-nucleotidase (5'-ribonucleotide phosphohydrolase, EC 3.1.3.5) was increased 44-fold for AMP and 7-fold for dAMP in B lymphoblasts. A model for the regulation of deoxyadenosine nucleotide synthesis by 5'-nucleotidase activity is proposed on the basis of the observations.
在培养的人类细胞中研究了脱氧腺苷代谢，以阐明T淋巴母细胞敏感性和B淋巴母细胞对脱氧腺苷毒性抗性的生化基础。在50 - 300微摩尔的脱氧腺苷浓度下，T淋巴母细胞合成脱氧腺苷核苷酸的能力比B淋巴母细胞大20至45倍。在dATP合成过程中，T淋巴母细胞积累大量dADP，而B淋巴母细胞不积累dADP。在这些细胞中检测了影响脱氧腺苷核苷酸合成的酶。脱氧腺苷激酶（ATP：脱氧腺苷5'-磷酸转移酶，EC 2.7.1.76）或脱氧腺苷酸激酶[ATP：（d）AMP磷酸转移酶，EC 2.7.4.11]的活性没有明显差异。B淋巴母细胞中5'-核苷酸酶（5'-核糖核苷酸磷酸水解酶，EC 3.1.3.5）的活性对于AMP增加了44倍，对于dAMP增加了7倍。基于这些观察结果，提出了一个由5'-核苷酸酶活性调节脱氧腺苷核苷酸合成的模型。
