Intracellular protein breakdown in non-growing cells of Escherichia coli.
1. When Escherichia coli leu(-) was incubated at 35 degrees in a medium based on minimal medium, but with the omission of phosphate ions, or glucose, or NH(4) (+) ions and leucine, intracellular protein was degraded at a rate of about 5%/hr. in each case. If Mg(2+) ions were omitted, however, the rate of degradation was 2.9%/hr. 2. Under certain conditions of incubation, protein degradation was inhibited. The inhibitor was neither NH(4) (+) ions nor amino acids, and its properties were not those of a protein, but it might be an unstable species of RNA. 3. Although a large part of the cell protein was degraded at about 5%/hr. during starvation of NH(4) (+) ions and leucine, some proteins were lost at more rapid rates, whereas others were lost at lower rates or not at all. 4. In particular, beta-galactosidase activity was lost at about 8%/hr. during starvation of NH(4) (+) ions and leucine, whereas d-serine-deaminase and alkaline-phosphatase activities were stable. During starvation of Mg(2+) ions, all three enzyme activities were stable.
D000469:Alkaline Phosphatase / Q000378:metabolism; D000596:Amino Acids / Q000032:analysis; D001426:Bacterial Proteins / Q000378:metabolism*; D001431:Bacteriological Techniques; D001433:Bacteriolysis; D002247:Carbon Isotopes; D002701:Chloramphenicol / Q000494:pharmacology; D004790:Enzyme Induction; D004926:Escherichia coli / Q000254:growth & development / Q000378:metabolism*; D005696:Galactosidases / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D006836:Hydro-Lyases / Q000378:metabolism; D007700:Kinetics; D007930:Leucine / Q000378:metabolism; D008274:Magnesium / Q000378:metabolism; D009705:Nucleosides; D010710:Phosphates / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D012313:RNA / Q000494:pharmacology; D014465:Ultrasonics; D014633:Valine / Q000032:analysis
D000596:Amino Acids; D001426:Bacterial Proteins; D002247:Carbon Isotopes; D009705:Nucleosides; D010710:Phosphates; D000644:Quaternary Ammonium Compounds; D012313:RNA; D002701:Chloramphenicol; D000469:Alkaline Phosphatase; D005696:Galactosidases; D006836:Hydro-Lyases; D007930:Leucine; D014633:Valine; D008274:Magnesium; D005947:Glucose