title: Uptake of tetracycline by membrane preparations from Escherichia coli.
abstract: 1. A membrane fraction from Escherichia coli has been prepared essentially free from ribosomes by treatment of the membranes with Triton X-100 at 0 degrees C followed by differential centrifugation. 2. The ribosome-free membrane vesicles absorbed tetracycline by a reversible temperature-dependent process with an apparent K(m) of 0.029mm at pH7.5 and 37 degrees C. 3. The absorption process was negligible below 25 degrees C and had an optimum at 40 degrees C; a pH optimum at 7.5 was observed. 4. The absorption of tetracycline was strongly inhibited by EDTA and ATP; ADP inhibited less strongly and AMP had no effect. 5. There was no significant difference in the rates or extent of uptake of tetracycline by membranes prepared from tetracycline-sensitive and tetracycline-resistant, R-factor-bearing E. coli.
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis; D001665:Binding Sites; D002458:Cell Fractionation; D002462:Cell Membrane / Q000378:metabolism*; D004269:DNA, Bacterial / Q000032:analysis; D004926:Escherichia coli / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D008854:Microscopy, Electron; D012329:RNA, Bacterial / Q000032:analysis; D012270:Ribosomes; D013501:Surface-Active Agents; D013696:Temperature; D013752:Tetracycline / Q000378:metabolism*; D014316:Tritium; D014461:Ultracentrifugation
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012329:RNA, Bacterial; D013501:Surface-Active Agents; D014316:Tritium; D013752:Tetracycline