Watanabe Kimiko, Tomioka Satsuki, Tanimura Kiyoko, Oku Hisae, Isoi Koichiro
School of Pharmacy and Pharmaceutical Sciences, Mukogawa Women's University, 11-68 Kyubancho, Koshien, Nishinomiya, Hyogo 633-8179, Japan.
Biosci Biotechnol Biochem. 2011;75(1):7-12. doi: 10.1271/bbb.100063. Epub 2011 Jan 7.
The uptake activity ratio for AMP, ADP, and ATP in mutant (T-1) cells of Escherichia coli W, deficient in de novo purine biosynthesis at a point between IMP and 5-aminoimidazole-4-carboxiamide-1-β-D-ribofuranoside (AICAR), was 1:0.43:0.19. This ratio was approximately equal to the 5'-nucleotidase activity ratio in E. coli W cells. The order of inhibitory effect on [2-³H]ADP uptake by T-1 cells was adenine > adenosine > AMP > ATP. About 2-fold more radioactive purine bases than purine nucleosides were detected in the cytoplasm after 5 min in an experiment with [8-¹⁴C]AMP and T-1 cells. Uptake of [2-³H]adenosine in T-1 cells was inhibited by inosine, but not in mutant (Ad-3) cells of E. coli W, which lacked adenosine deaminase and adenylosuccinate lyase. These experiments suggest that AMP, ADP, and ATP are converted mainly to adenine and hypoxanthine via adenosine and inosine before uptake into the cytoplasm by E. coli W cells.
在从头嘌呤生物合成途径中，于次黄嘌呤核苷酸（IMP）和5-氨基咪唑-4-甲酰胺-1-β-D-呋喃核糖苷（AICAR）之间某一点存在缺陷的大肠杆菌W突变体（T-1）细胞中，AMP、ADP和ATP的摄取活性比为1:0.43:0.19。该比例与大肠杆菌W细胞中的5'-核苷酸酶活性比大致相等。T-1细胞对[2-³H]ADP摄取的抑制作用顺序为：腺嘌呤＞腺苷＞AMP＞ATP。在用[8-¹⁴C]AMP和T-1细胞进行的实验中，5分钟后在细胞质中检测到的放射性嘌呤碱比嘌呤核苷多约2倍。T-1细胞中[2-³H]腺苷的摄取受到肌苷的抑制，但在缺乏腺苷脱氨酶和腺苷酸琥珀酸裂解酶的大肠杆菌W突变体（Ad-3）细胞中则不受抑制。这些实验表明，AMP、ADP和ATP在被大肠杆菌W细胞摄取到细胞质之前，主要通过腺苷和肌苷转化为腺嘌呤和次黄嘌呤。
