title: Synthesis of pppGpp by ribosomes from an Escherichia coli spoT mutant and the metabolic relationship between pppGpp and ppGpp.
abstract: 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.
mesh_terms: D003600:Cytosol / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D005796:Genes; D006150:Guanine Nucleotides / Q000096:biosynthesis*; D006158:Guanosine Pentaphosphate / Q000096:biosynthesis*; D006159:Guanosine Tetraphosphate / Q000096:biosynthesis*; D007700:Kinetics; D009154:Mutation; D012270:Ribosomes / Q000378:metabolism*
chemical_list: D006150:Guanine Nucleotides; D006159:Guanosine Tetraphosphate; D006158:Guanosine Pentaphosphate