This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hutkins, R Articles by McKay, L L Search for Related Content PubMed PubMed Citation Articles by Hutkins, R Articles by McKay, L L Agricola Articles by Hutkins, R Articles by McKay, L L

 Previous Article  |  Next Article 

Appl Environ Microbiol. 1985 October; 50(4): 772-776

Galactose transport in Streptococcus thermophilus.

R Hutkins, H A Morris and L L McKay

ABSTRACT

Although Streptococcus thermophilus accumulated [14C]lactose in the absence of an endogenous energy source, galactose-fermenting (Gal+) cells were unable to accumulate [14C]galactose unless an additional energy source was added to the test system. Both Gal+ and galactose-nonfermenting (Gal-) strains transported galactose when preincubated with sucrose. Accumulation was inhibited 50 or 95% when 10 mM sodium fluoride or 1.0 mM iodoacetic acid, respectively, was added to sucrose-treated cells, indicating that ATP was required for galactose transport activity. Proton-conducting ionophores also inhibited galactose uptake, although N,N'-dicyclohexyl carbodiimide had no effect. The results suggest that galactose transport in S. thermophilus occurs via an ATP-dependent galactose permease and that a proton motive force is involved. The galactose permease in S. thermophilus TS2b (Gal+) had a Km for galactose of 0.25 mM and a Vmax of 195 micromol of galactose accumulated per min per g (dry weight) of cells. Several structurally similar sugars inhibited galactose uptake, indicating that the galactose permease had high affinities for these sugars.

---

Appl Environ Microbiol. 1985 October; 50(4): 772-776

This article has been cited by other articles:

• van den Bogaard, P. T. C., Kleerebezem, M., Kuipers, O. P., de Vos, W. M. (2000). Control of Lactose Transport, beta -Galactosidase Activity, and Glycolysis by CcpA in Streptococcus thermophilus: Evidence for Carbon Catabolite Repression by a Non-Phosphoenolpyruvate-Dependent Phosphotransferase System Sugar. J. Bacteriol. 182: 5982-5989 [Abstract] [Full Text]