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): 777-780

Galactokinase activity in Streptococcus thermophilus.

R Hutkins, H A Morris and L L McKay

ABSTRACT

ATP-dependent phosphorylation of [14C]galactose by 11 strains of Streptococcus thermophilus indicated that these organisms possessed the Leloir enzyme, galactokinase (galK). Activities were 10 times higher in fully induced, galactose-fermenting (Gal+) strains than in galactose-nonfermenting (Gal-) strains. Lactose-grown, Gal- cells released free galactose into the medium and were unable to utilize residual galactose or to induce galK above basal levels. Gal+ S. thermophilus 19258 also released galactose into the medium, but when lactose was depleted growth on galactose commenced, and galK increased from 0.025 to 0.22 micromol of galactose phosphorylated per min per mg of protein. When lactose was added to galactose-grown cells of S. thermophilus 19258, galK activity rapidly decreased. These results suggest that galK in Gal+ S. thermophilus is subject to an induction-repression mechanism, but that galK cannot be induced in Gal- strains.

---

Appl Environ Microbiol. 1985 October; 50(4): 777-780

This article has been cited by other articles:

• de Vin, F., Radstrom, P., Herman, L., De Vuyst, L. (2005). Molecular and Biochemical Analysis of the Galactose Phenotype of Dairy Streptococcus thermophilus Strains Reveals Four Different Fermentation Profiles. Appl. Environ. Microbiol. 71: 3659-3667 [Abstract] [Full Text]  
• Vaillancourt, K., LeMay, J.-D., Lamoureux, M., Frenette, M., Moineau, S., Vadeboncoeur, C. (2004). Characterization of a Galactokinase-Positive Recombinant Strain of Streptococcus thermophilus. Appl. Environ. Microbiol. 70: 4596-4603 [Abstract] [Full Text]  
• Broadbent, J. R., McMahon, D. J., Welker, D. L., Oberg, C. J., Moineau, S. (2003). Biochemistry, Genetics, and Applications of Exopolysaccharide Production in Streptococcus thermophilus: A Review. J DAIRY SCI 86: 407-423 [Abstract] [Full Text]  
• Levander, F., Svensson, M., Radstrom, P. (2002). Enhanced Exopolysaccharide Production by Metabolic Engineering of Streptococcus thermophilus. Appl. Environ. Microbiol. 68: 784-790 [Abstract] [Full Text]  
• Vaillancourt, K., Moineau, S., Frenette, M., Lessard, C., Vadeboncoeur, C. (2002). Galactose and Lactose Genes from the Galactose-Positive Bacterium Streptococcus salivarius and the Phylogenetically Related Galactose-Negative Bacterium Streptococcus thermophilus: Organization, Sequence, Transcription, and Activity of the gal Gene Products. J. Bacteriol. 184: 785-793 [Abstract] [Full Text]  
• Levander, F., Rådström, P. (2001). Requirement for Phosphoglucomutase in Exopolysaccharide Biosynthesis in Glucose- and Lactose-Utilizing Streptococcus thermophilus. Appl. Environ. Microbiol. 67: 2734-2738 [Abstract] [Full Text]  
• Vaughan, E. E., van den Bogaard, P. T. C., Catzeddu, P., Kuipers, O. P., de Vos, W. M. (2001). Activation of Silent gal Genes in the lac-gal Regulon of Streptococcus thermophilus. J. Bacteriol. 183: 1184-1194 [Abstract] [Full Text]