Transport of glycine-betaine by Listeria monocytogenes.
Uptake of [14C]glycine-betaine by Listeria monocytogenes was stimulated by NaCl with optimal stimulation at 0.4-0.5 M. The glycine-betaine transport system had a Km of 22 microM and a Vmax of 11.7 nmol-1 min-1 mg-1 protein when grown in the absence of NaCl. When grown in the presence of 0.8 M NaCl the Vmax increased to 27.0 nmol-1 min-1 mg-1 protein in 0.8 M NaCl. At NaCl concentrations above 0.5 M the uptake rate of glycine-betaine was reduced. Measurement of intracellular K+ concentrations and fluorescent dye quenching indicated that higher NaCl concentrations also led to a decrease in the electrochemical potential difference across the cytoplasmic membrane. Uptake of glycine was also observed, but this was not stimulated by NaCl.
Institute of Food Research, Reading, United Kingdom.
R A
RA
Patchett
A F
AF
Kelly
R G
RG
Kroll
D001622:Betaine / Q000378:metabolism*; D001693:Biological Transport, Active / Q000187:drug effects; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D004563:Electrochemistry; D007700:Kinetics; D008089:Listeria monocytogenes / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects; D009994:Osmolar Concentration; D011392:Proline / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology
D001622:Betaine; D012965:Sodium Chloride; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D011392:Proline