Glutathione S-transferase from oxadiazon treated chickpea

Glutathione S-transferase was purified more than 150-fold with ca 70% recovery from chickpea shoots after treatment with 10 ppm of the herbicide oxadiazon. The purification steps involved ammonium sulphate precipitation, gel filtration and affinity chromatography. The M_r weight of the native enzyme was 47 000 as determined by gel filtration and the enzyme was separated by ion exchange chromatography into five distinct isozymes named according to their elution order from a DEAE-Sephacel column as GST-I to GST-V. Sodium dodecyl sulfate-polyacrylamide electrophoresis analysis revealed the presence of one type of subunit for GST-I and GST-II with an apparent M_r of 27 000 while the other three isozymes (GST-III, GST-IV and GST-V) displayed two types of subunits with M_rs 29 000 and 27 000. Antibodies raised against the purified chickpea shoot glutathione S-transferase gave a single precipitin line with both wheat and corn extracts but only partial cross-reactivity was observed with purified human placenta enzyme.