Chen S F, Stoeckler J D, Parks R E
Biochem Pharmacol. 1984 Dec 15;33(24):4069-79. doi: 10.1016/0006-2952(84)90023-6.
The assay of residual adenosine deaminase (ADA) activity was used as a sensitive measure of the transport of deoxycoformycin (dCF) into human erythrocytes. Contrary to prior reports from this laboratory, the inactivation of intraerythrocytic ADA by dCF was linear rather than log-linear, with time. Linear inactivation rates were also seen when erythrocytes were preloaded with a 5-fold excess of calf intestinal ADA. The uptake of tritium-labeled dCF molecules and the rate of inactivation of ADA molecules showed an approximate 1:1 stoichiometry. The nucleoside transport inhibitors, 6-[(4-nitrobenzyl)thio]-9-beta-D-ribofuranosylpurine (NBMPR) and dipyridamole, and the permeant, uridine, inhibited dCF transport with Ki values of 35 nM, 45 nM, and 340 microM respectively. The affinity of dCF for the nucleoside transporter was low with a Ki of approximately 10 mM for the inhibition of adenosine influx.
残余腺苷脱氨酶（ADA）活性测定被用作衡量脱氧助间型霉素（dCF）转运至人红细胞的敏感指标。与本实验室之前的报告相反，dCF对红细胞内ADA的失活作用随时间呈线性而非对数线性关系。当红细胞预先加载5倍过量的小牛肠ADA时，也观察到了线性失活速率。氚标记的dCF分子摄取量与ADA分子失活速率显示出近似1:1的化学计量关系。核苷转运抑制剂6-[(4-硝基苄基)硫基]-9-β-D-呋喃核糖基嘌呤（NBMPR）和双嘧达莫，以及通透剂尿苷，分别以35 nM、45 nM和340 μM的Ki值抑制dCF转运。dCF对核苷转运体的亲和力较低，抑制腺苷内流的Ki约为10 mM。
