Camici M, Mura U, Cellini F, Del Corso A, Turchi G, Ipata P L
Dipartimento di Fisiologia e Biochimica, Laboratori di Biochimica, Pisa, Italy.
Arch Biochem Biophys. 1988 Sep;265(2):234-40. doi: 10.1016/0003-9861(88)90123-3.
A variant clone of cultured chinese hamster lung fibroblasts (V79), selected for resistance to 8-azaguanine (V79 azagrst), although lacking hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8), is able to convert hypoxanthine into IMP via purine-nucleoside phosphorylase (EC 2.4.2.1) and nucleoside kinase. In addition to the phosphoribosylation pathway, we also present evidence for the occurrence of a kinase-mediated pathway of recovery of hypoxanthine in the wild-type cells. The lower rate of formation of IMP in the V79 azagrst cells, apparently correlated with the phosphorylation of the nucleoside, suggests possible differences in the catalytic and/or regulatory properties of nucleoside kinase in the two cell lines. This fact might be of particular relevance in evaluating the mechanisms of resistance to purine analogs displayed by several cell types.
一株经过筛选获得8-氮杂鸟嘌呤抗性的中国仓鼠肺成纤维细胞（V79）变异克隆株（V79 azagrst），尽管缺乏次黄嘌呤-鸟嘌呤磷酸核糖转移酶（EC 2.4.2.8），但仍能够通过嘌呤核苷磷酸化酶（EC 2.4.2.1）和核苷激酶将次黄嘌呤转化为肌苷一磷酸（IMP）。除了磷酸核糖基化途径外，我们还提供证据表明在野生型细胞中存在一种激酶介导的次黄嘌呤回收途径。V79 azagrst细胞中IMP形成速率较低，这显然与核苷的磷酸化有关，表明两种细胞系中核苷激酶的催化和/或调节特性可能存在差异。这一事实在评估几种细胞类型对嘌呤类似物的抗性机制时可能具有特别重要的意义。
