title: Differentiation between binding and transport of dansylgalactosides in Escherichia coli.
abstract: The results presented in this paper confirm and extend previous observations which indicate that fluorescent dansylgalactsodes bind to the beta-galactoside carrier protein but do not penetrate the cytoplasmic membrane. The conclusion is supported by the following observations. (a) Although 2'-(N-dansyl)aminoethyl-beta-D-thiogalactopyranoside and 2'-(N-dansyl)aminoethyl-beta-D-galactopyranoside are competitive inhibitors of lactose transport in intact cells of Escherichia coli and induce the in vitro synthesis of beta-galactosidase, they do not induce beta-galactosidase in vivo. (b) p-Chloromercuribenzenesulfonate does not cause efflux of lactose from the intravesicular pool, but causes rapid reversal of D-lactate-induced dansylgalactoside fluorescence. (c) Dansylgalactosides inhibit dilution-induced, carrier-mediated lactose efflux.
mesh_terms: D002731:4-Chloromercuribenzenesulfonate / Q000494:pharmacology; D001692:Biological Transport; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D003619:Dansyl Compounds / Q000494:pharmacology*; D004790:Enzyme Induction / Q000187:drug effects; D004926:Escherichia coli / Q000378:metabolism*; D005696:Galactosidases / Q000096:biosynthesis; D005697:Galactosides / Q000378:metabolism / Q000494:pharmacology*; D006027:Glycosides / Q000494:pharmacology*; D007700:Kinetics; D007785:Lactose / Q000378:metabolism*; D011955:Receptors, Drug; D014050:Toluene / Q000494:pharmacology
chemical_list: D003619:Dansyl Compounds; D005697:Galactosides; D006027:Glycosides; D011955:Receptors, Drug; D014050:Toluene; D002731:4-Chloromercuribenzenesulfonate; D005696:Galactosidases; D007785:Lactose