Plant glutathione transferases

Methods Enzymol. 2005;401:169-86. doi: 10.1016/S0076-6879(05)01011-6.

Abstract

Soluble plant glutathione transferases (GSTs) consist of seven distinct classes, six of which have been functionally characterized. The phi and tau class GSTs are specific to plants and the most numerous and abundant of these enzymes. Both have classic conjugating activities toward a diverse range of xenobiotics, including pesticides, where they are major determinants of herbicide selectivity in crops and weeds. In contrast, the zeta and theta class GSTs are conserved in animals and plants and have very restricted activities toward xenobiotics. Theta GSTs function as glutathione peroxidases, reducing organic hydroperoxides produced during oxidative stress. Zeta GSTs act as glutathione-dependent isomerases, catalyzing the conversion of maleylacetoacetate to fumarylacetoacetate, the penultimate step in tyrosine degradation. The other two classes of plant GSTs, the dehydroascorbate reductases (DHARs) and lambda GSTs, differ from phi, tau, zeta, and theta enzymes in being monomers rather than dimers and possessing a catalytic cysteine rather than serine in the active site. Both can function as thioltransferases, with the DHARs having a specialized function in reducing dehydroascorbate to ascorbic acid. The determination of the diverse plant-specific functions of the differing GST classes is described.

MeSH terms

  • Carboxylic Acids / chemistry
  • Carboxylic Acids / metabolism
  • Glutathione Transferase* / chemistry
  • Glutathione Transferase* / genetics
  • Glutathione Transferase* / metabolism
  • Isoenzymes* / chemistry
  • Isoenzymes* / genetics
  • Isoenzymes* / metabolism
  • Lipid Peroxides / chemistry
  • Lipid Peroxides / metabolism
  • Molecular Structure
  • Plant Proteins* / chemistry
  • Plant Proteins* / genetics
  • Plant Proteins* / metabolism
  • Protein Subunits / chemistry
  • Protein Subunits / genetics
  • Protein Subunits / metabolism

Substances

  • Carboxylic Acids
  • Isoenzymes
  • Lipid Peroxides
  • Plant Proteins
  • Protein Subunits
  • Glutathione Transferase