Glutathione transport systems of the budding yeast saccharomyces cerevisiae

Abstract

The budding yeast Saccharomyces cerevisiae was shown to have two kinetically distinguishable glutathione transport systems. While one with high affinity (GSH-P1; KT=0.045 mM) was regulated, the other with low affinity (GSH-P2; KT>2 mM) was not. GSH-P1 was highly specific to glutathione, and its activity was quickly lost by suspending the cells in buffer solutions. This activity loss was not observed if glucose-containing buffer was used. In addition, ρ − isolates had only about one half of the glutathione transport activity of the original (ρ +) strain. Therefore, it is concluded that GSH-P1 is an ATP-driven transport system. Strong and moderate inhibition of GSH-P1 by protonophores and ionophores, respectively, are attributed to competition for ATP between GSH-P1 and proton- and cation-pumps, re. © 1998 Japan Society for Bioscience, Biotechnology, and Agrochemistry.