Leung K L, Yamazaki H
Can J Biochem. 1977 Dec;55(12):1207-12. doi: 10.1139/o77-180.
Both ribosomes and a cell-free extract (S-30) prepared from an Escherichia coli spoT mutant catalyzed the synthesis of guanosine pentaphosphate (pppGpp) and guanosine tetraphosphate (ppGpp) as efficiently as did ribosomes and S-30 from a spoT+ strain. In both cases, the level of pppGpp reached its maximum before ppGpp maximally accumulated. pppGpp added to the ribosome system was rapidly converted to ppGpp. These results indicate that the spoT+ gene product may not have a direct role in the synthesis of pppGpp and that pppGpp is a precursor of ppGpp.
核糖体以及从大肠杆菌spoT突变体制备的无细胞提取物（S-30）催化合成鸟苷五磷酸（pppGpp）和鸟苷四磷酸（ppGpp）的效率与来自spoT+菌株的核糖体和S-30相同。在这两种情况下，pppGpp的水平在ppGpp最大积累之前达到最大值。添加到核糖体系统中的pppGpp迅速转化为ppGpp。这些结果表明，spoT+基因产物可能在pppGpp的合成中没有直接作用，并且pppGpp是ppGpp的前体。
