Jain A, Tyagi A K
Department of Biochemistry, V.P. Chest Institute, Delhi, India.
Mol Cell Biochem. 1987 Nov;78(1):3-8. doi: 10.1007/BF00224418.
All three polyamines - putrescine, spermidine and spermine stimulated the activity of mycobacterial RNA polymerase in vitro although the concentration required for maximal stimulation was different for each of the amines. Spermidine and spermine showed a biphasic effect on the enzyme activity. Stimulation of RNA synthesis by spermidine occurs only at higher DNA template/enzyme ratio. Spermidine stimulates RNA synthesis by acting on the elongation phase of RNA synthesis but it had no effect on initiation phase. Addition of mycobacterial RNA to the assay mixture resulted in the inhibition of RNA polymerase activity and this inhibition could be reversed by spermidine suggesting that spermidine stimulates transcription by binding to nascent RNA and thus destabilizing the short DNA-RNA hybrid region.
三种多胺——腐胺、亚精胺和精胺均能在体外刺激分枝杆菌RNA聚合酶的活性，尽管每种胺达到最大刺激所需的浓度不同。亚精胺和精胺对该酶活性呈现双相效应。亚精胺仅在较高的DNA模板/酶比例下刺激RNA合成。亚精胺通过作用于RNA合成的延伸阶段来刺激RNA合成，但对起始阶段没有影响。向测定混合物中添加分枝杆菌RNA会导致RNA聚合酶活性受到抑制，而这种抑制可被亚精胺逆转，这表明亚精胺通过与新生RNA结合，从而使短的DNA-RNA杂交区域不稳定来刺激转录。
