Glucose transport in a methylotrophic yeast Hansenula polymorpha

Glucose transport was studied in a methylotrophic yeast Hansenula polymorpha . Two kinetically different glucose transport systems were revealed in cells grown under different growth conditions. Glucose-repressed cells exhibited a low-affinity transport system ( K _m for glucose 1.75 mM) while glucose-derepressed and ethanol-grown cells had a high-affinity transport system ( K _m for glucose 0.05–0.06 mM). The high- and low-affinity transport systems differed in substrate specificity, sensitivity to pH, dinitrophenol and protonophore carbonyl cyanide- m -chlorophenyl-hydrazone. The kinetic rearrangement of the glucose transport system in response to altered growth conditions was dependent on de novo protein synthesis.