Ho Y K, Aradi J, Bardos T J
Nucleic Acids Res. 1980 Jul 25;8(14):3175-91. doi: 10.1093/nar/8.14.3175.
5'Mercaptouridine-5'-diphosphate (hs5UDP) has been synthesized and investigated as a substrate of the polynucleotide phosphorylase of Micrococcus luteus. While hs5UDP is not utilized alone, it can be copolymerized with UDP; however, unusually for this enzyme, the ratio of 5'mercaptouridylate vs. uridylate residues in the polynucleotide product (MPU) is always lower than the ratio of hs5UDP v. UDP in the substrate mixture. Furthermore, hs5UDP decreases the rate of the enzymic polymerization reaction. The MPU product forms two-stranded and three-stranded complexes with poly(A). The circular dichroic spectra of these complexes are similar to those formed between poly(U) and poly(A), but their melting profiles indicate somewhat lower stability. The physicochemical and biochemical properties of the enzymic product are qualitatively similar to those of MPU prepared by chemical modification; both are potent inhibitors of a DNA-dependent RNA polymerase.
5'-巯基尿苷-5'-二磷酸（hs5UDP）已被合成，并作为藤黄微球菌多核苷酸磷酸化酶的底物进行了研究。虽然hs5UDP不能单独被利用，但它可以与UDP共聚；然而，对于这种酶来说，不同寻常的是，多核苷酸产物（MPU）中5'-巯基尿苷酸与尿苷酸残基的比例总是低于底物混合物中hs5UDP与UDP的比例。此外，hs5UDP会降低酶促聚合反应的速率。MPU产物与聚（A）形成双链和三链复合物。这些复合物的圆二色光谱与聚（U）和聚（A）之间形成的光谱相似，但它们的解链曲线表明稳定性略低。酶促产物的物理化学和生化性质在定性上与通过化学修饰制备的MPU相似；两者都是DNA依赖性RNA聚合酶的有效抑制剂。
