Uptake of galactose into Escherichia coli by facilitated diffusion

J Gen Microbiol. 1976 May;94(1):75-89. doi: 10.1099/00221287-94-1-75.

Abstract

Strains of Escherichia coli devoid of systems for the active transport of galactose (galP mgl) still grow on galactose but at rates that are a function of the galactose concentration of the medium: half-maximal growth rates require more than 2 mM-galactose to be present. Evidence is presented that galactose is taken up by such strains by facilitated diffusion on a carrier specified by the umg gene (or by a gene highly co-transducible with it) which is thus a part of, or closely associated with, an enzyme II for glucose of the phosphoenolpyruvate-phosphotransferase system. However, the entry of galactose does not require phosphotransferase activity, and the sugar taken up appears in the cells as free galactose.

MeSH terms

  • Diffusion
  • Escherichia coli / enzymology
  • Escherichia coli / growth & development
  • Escherichia coli / metabolism*
  • Galactose / metabolism*
  • Genes
  • Glucose / pharmacology
  • Methylgalactosides / metabolism
  • Mutation
  • Phosphotransferases / metabolism

Substances

  • Methylgalactosides
  • Phosphotransferases
  • Glucose
  • Galactose