Phytochelatins are synthesized by two vacuolar serine carboxypeptidases in Saccharomyces cerevisiae

FEBS Lett. 2007 Apr 17;581(8):1681-7. doi: 10.1016/j.febslet.2007.03.039. Epub 2007 Mar 28.

Abstract

Phytochelatins (PCs) are cysteine-rich peptides that chelate heavy metal ions, thereby mediating heavy metal tolerance in plants, fission yeast, and Caenorhabditis elegans. They are synthesized from glutathione by PC synthase, a specific dipeptidyltransferase. While Saccharomyces cerevisiae synthesizes PCs upon exposure to heavy metal ions, the S. cerevisiae genome does not encode a PC synthase homologue. How PCs are synthesized in yeast is unclear. This study shows that the vacuolar serine carboxypeptidases CPY and CPC are responsible for PC synthesis in yeast. The finding of a PCS-like activity of these enzymes in vivo discloses another route for PC biosynthesis in eukaryotes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Carboxypeptidases / genetics
  • Carboxypeptidases / metabolism*
  • Glutathione / biosynthesis*
  • Glutathione / genetics
  • Molecular Sequence Data
  • Phytochelatins
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism*
  • Vacuoles / enzymology

Substances

  • Saccharomyces cerevisiae Proteins
  • Phytochelatins
  • Carboxypeptidases
  • CPC protein, S cerevisiae
  • CPY protein, S cerevisiae
  • Glutathione