title: Protein synthesis and degradation in a leucine auxotroph of Escherichia coli.
abstract: The synthesis and degradation of the soluble and sodium dodecyl sulfate-(SDS)-solubilized protein fractions of Escherichia coli were studied in both growing and nongrowing cultures. When separated according to molecular weight on SDS-polyacrylamide gels, the proteins of both fractions of growing cells undergo no measureable differential synthesis or degradation during logarithmic growth. However, when a leucine auxotroph is suspended in medium containing 5.3 muM leucine (a level that will not sustain growth), the SDS-solubilized protein of such a nongrowing culture shows a rapid synthesis of two protein components (32,000 and 12,000 daltons) found only in the out membrane.
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism*; D007700:Kinetics; D007930:Leucine / Q000378:metabolism*; D008565:Membrane Proteins / Q000096:biosynthesis / Q000378:metabolism*; D008970:Molecular Weight
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; D007930:Leucine