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Arch Microbiol. 1994;162(3):205-10.

Transport of glycine-betaine by Listeria monocytogenes.

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Institute of Food Research, Reading, United Kingdom.


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.

[Indexed for MEDLINE]

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