Glutathione and gamma-glutamyl transferases are involved in the formation of cadmium-glutathione complex

In a wild-type strain of Saccharomyces cerevisiae, cadmium induces the activities of both gamma-glutamyl transferase (gamma-GT) and glutathione transferase 2 (Gtt2). However, Gtt2 activity did not increase under gamma-GT or Ycf1 deficiencies, suggesting that the accumulation of glutathione- cadmium in the cytosol inhibits Gtt2. On the other hand, the balance between the cytoplasmic and vacuolar level of glutathione seems to regulate gamma-GT activity, since this enzyme was not activated in a gtt2 strain. Taken together, these results suggest that gamma-GT and Gtt2 work together to remove cadmium from the cytoplasm, a crucial mechanism for metal detoxification that is dependent on glutathione. (C) 2009 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.