title: Regulation of glutamine synthetase. X. Effect of growth conditions on the susceptibility of Escherichia coli glutamine synthetase to feedback inhibition.
abstract: The kinetic properties of Escherichia coli glutamine synthetase are markedly influenced by the manner in which the organism is grown. Enzyme obtained from stationary-phase cells grown on glycerol and glutamate is strongely inhibited by each of the eight feedback effectors known to influence this enzyme; however, the enzyme from log-phase cells grown on glucose and growth-limiting concentrations of NH(4)Cl is stimulated by some of these effectors. Of the growth variables examined, nitrogen source and time of harvest were the most important; carbon source and aeration seemed to have no effect. Two purified enzyme preparations have been obtained from cells grown under two different conditions, designated enzymes I and II for convenience. Enzyme I is stimulated by adenosine 5'-monophosphate, histidine, and tryptophan in the transfer assay, whereas enzyme II is strongly inhibited by all effectors tested. Enzyme I has a higher specific activity in the forward assay in the presence of Mg(++) or Co(++), whereas enzyme II is more active in the presence of Mn(++).
mesh_terms: D000227:Adenine Nucleotides / Q000494:pharmacology; D000409:Alanine / Q000494:pharmacology; D000643:Ammonium Chloride / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D003035:Cobalt / Q000494:pharmacology; D003470:Culture Media; D003597:Cytosine Nucleotides / Q000494:pharmacology; D004926:Escherichia coli / Q000201:enzymology* / Q000254:growth & development; D005246:Feedback; D005947:Glucose / Q000494:pharmacology; D005971:Glutamates / Q000494:pharmacology; D005973:Glutamine / Q000378:metabolism; D005990:Glycerol / Q000494:pharmacology; D005998:Glycine / Q000494:pharmacology; D006639:Histidine / Q000494:pharmacology; D007930:Leucine / Q000494:pharmacology; D008025:Ligases / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000378:metabolism; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D009573:Nitrites / Q000494:pharmacology; D010100:Oxygen / Q000494:pharmacology; D014364:Tryptophan / Q000494:pharmacology
chemical_list: D000227:Adenine Nucleotides; D003470:Culture Media; D003597:Cytosine Nucleotides; D005971:Glutamates; D009573:Nitrites; D000643:Ammonium Chloride; D005973:Glutamine; D003035:Cobalt; D008345:Manganese; D006639:Histidine; D014364:Tryptophan; D008025:Ligases; D007930:Leucine; D008274:Magnesium; D005947:Glucose; D000409:Alanine; D005990:Glycerol; D010100:Oxygen; D002118:Calcium; D005998:Glycine