Cloning and characterisation of plant theta and zeta class GSTs: Implications for plant GST classification

Plant GSTs form a diverse and complex family. Re-examination has identified four distinct plant GST classes, of which two (theta and zeta) have mammal ian homologues and two (phi and tall) are unique to plants. A nomenclature system for plant GSTs has been developed based on this classification. Zeta and theta class enzymes have been cloned and characterised from the model plant Arabidopsis thaliana. AtGSTZ1-1, a zeta enzyme, has no detectable GST activity but has maleylacetone isomerase and dichloroacetate oxygenase act ivities. AtCSTT1-1, a theta enzyme, has high GST activity towards 4-nitrobe nzyl chloride and very high glutathione peroxidase activity. (C) 2001 Elsev ier Science Ireland Ltd. All rights reserved.