Sawai H, Taira H, Ishibashi K, Itoh M
J Biochem. 1987 Feb;101(2):339-46. doi: 10.1093/oxfordjournals.jbchem.a121918.
beta-Alanyltyrosine derivative of 2',5'-tetraadenylate 5'-triphosphate, pppA2'p5'A2'-p5'A2'p5'A-beta-Ala-Tyr was prepared by coupling of periodate-oxidized pppA2'p5'-A2'p5'A2'p5'A with beta-alanyltyrosine methyl ester, followed by reduction with sodium cyanoborohydride. Its stability to 2',5'-phosphodiesterase and phosphatase was investigated in mouse L cell extract. The 5'-triphosphate of the compound was cleaved gradually to form the 5'-dephosphorylated derivative, A2'p5'A2'p5'A2'p5'A-beta-Ala-Tyr, followed by slow degradation of the 2',5'-phosphodiester bond. On the other hand, pppA2'p5'A2'p5'A2'p5'A was hydrolyzed very quickly under the same conditions. The tetramer derivative bound tightly to the 2',5'-oligoadenylate-dependent endoribonuclease in rabbit reticulocyte lysate or mouse L cell extract and inhibited protein synthesis of mouse L cells more effectively than the unmodified 2',5'-tetraadenylate 5'-triphosphate. The corresponding trimer derivative had slightly weaker activities than the unmodified trimer for binding to the endoribonuclease and for inhibition of protein synthesis. The compound, pppA2'p5'A2'p5'-A2'p5'A-beta-Ala-Tyr, was iodinated easily at the tyrosine residue with 125I, giving a high-specific-radioactivity derivative which was used as a radio-labeled probe in a radiobinding assay for 2',5'-oligoadenylate.
2',5'-四腺苷酸5'-三磷酸的β-丙氨酰酪氨酸衍生物，即pppA2'p5'A2'-p5'A2'p5'A-β-丙氨酰酪氨酸，是通过将高碘酸盐氧化的pppA2'p5'-A2'p5'A2'p5'A与β-丙氨酰酪氨酸甲酯偶联，然后用氰基硼氢化钠还原制备而成。在小鼠L细胞提取物中研究了其对2',5'-磷酸二酯酶和磷酸酶的稳定性。该化合物的5'-三磷酸基团逐渐被裂解，形成5'-去磷酸化衍生物A2'p5'A2'p5'A2'p5'A-β-丙氨酰酪氨酸，随后2',5'-磷酸二酯键缓慢降解。另一方面，在相同条件下，pppA2'p5'A2'p5'A2'p5'A水解非常迅速。四聚体衍生物与兔网织红细胞裂解物或小鼠L细胞提取物中的2',5'-寡腺苷酸依赖性内切核糖核酸酶紧密结合，并且比未修饰的2',5'-四腺苷酸5'-三磷酸更有效地抑制小鼠L细胞的蛋白质合成。相应的三聚体衍生物在与内切核糖核酸酶结合和抑制蛋白质合成方面的活性比未修饰的三聚体略弱。化合物pppA2'p5'A2'p5'-A2'p5'A-β-丙氨酰酪氨酸在酪氨酸残基处容易被125I碘化，产生高比放射性衍生物，该衍生物用作2',5'-寡腺苷酸放射性结合测定中的放射性标记探针。
