Characterization of low- and high-affinity glucose transports in the yeast Kluyveromyces marxianus

Biochim Biophys Acta. 1987 Oct 16;903(3):425-33. doi: 10.1016/0005-2736(87)90049-6.

Abstract

Glucose transport in the yeast Kluyveromyces marxianus proceeds by two functionally and presumably structurally distinct transporters depending on the carbon source of the culture medium. In lactose-grown cells, glucose was taken up through a high-affinity H+-sugar symporter (Km = 0.09 mM), whereas a low-affinity transporter (Km = 3.5 mM) was utilized in glucose-grown cells. The two transporters exhibited different substrate specificities. Galactose was demonstrated to be a selective substrate of the H+-glucose symporter (Km = 0.14 mM) and did not significantly enter glucose-grown cells. Fructose was a preferential substrate of the low-affinity carrier (Km = 3.5 mM), but it entered lactose-grown cells through a high-affinity H+-fructose symporter distinct from the H+-glucose one. Other putative substrates of the two glucose transporters were identified by competition experiments. 2-Deoxyglucose recognized both carriers with a similar affinity, while the non-phosphorylatable analogues 6-deoxyglucose, 3-O-methylglucose and D-fucose exhibited a 10-30 fold preference for the high-affinity transporter.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • 3-O-Methylglucose
  • Biological Transport / drug effects
  • Carbonyl Cyanide m-Chlorophenyl Hydrazone / pharmacology
  • Deoxyglucose / metabolism
  • Fructose / metabolism
  • Fucose / metabolism
  • Galactose / metabolism
  • Glucose / metabolism*
  • Kinetics
  • Kluyveromyces / metabolism*
  • Methylglucosides / metabolism
  • Monosaccharide Transport Proteins / metabolism*
  • Saccharomycetales / metabolism*

Substances

  • Methylglucosides
  • Monosaccharide Transport Proteins
  • 3-O-Methylglucose
  • Fucose
  • Fructose
  • Carbonyl Cyanide m-Chlorophenyl Hydrazone
  • Deoxyglucose
  • Glucose
  • 6-deoxyglucose
  • Galactose