title: Relative levels of guanosine 5'-diphosphate 3'-diphosphate (ppGpp) in some N2 fixing bacteria during derepression and repression of nitrogenase.
abstract: Addition of ammonium to N2 fixing cultures of Azotobacter vinelandii, Klebsiella pneumoniae and Clostridium pasteurianum rapidly reduced the intracellular levels of guanosine 5'-diphosphate 3'-diphosphate (ppGpp) by 70-90%. This change might reflect a regulatory role of ppGpp in nitrogen metabolism.
mesh_terms: D001395:Azotobacter / Q000201:enzymology; D003013:Clostridium / Q000201:enzymology; D004794:Enzyme Repression; D005786:Gene Expression Regulation; D006150:Guanine Nucleotides / Q000378:metabolism*; D006159:Guanosine Tetraphosphate / Q000378:metabolism*; D007711:Klebsiella pneumoniae / Q000201:enzymology; D009586:Nitrogen Fixation; D009591:Nitrogenase / Q000235:genetics*
chemical_list: D006150:Guanine Nucleotides; D006159:Guanosine Tetraphosphate; D009591:Nitrogenase