Analysis and characterization of glutathione S-transferase subunits from wheat ( Triticum aestivum L.)

Abstract

The total subunit complement of glutathione S-transferases (GSTs) of wheat ( Triticum aestivum L.) was isolated by glutathione-agarose affinity chromatography. The proteins bound to the affinity column were analysed by SDS-PAGE, which separated six to seven protein bands. Reverse phase-HPLC analysis revealed six major and about 15 minor peaks. The amounts of three major components were increased upon treatment with the herbicide safener naphthalic anhydride. The six major components were isolated. Their relative molecular masses, determined by electrospray ionization mass spectrometry, were between 23 140±2 and 24 957±3 Da. The sequences of the 20 N-terminal amino acids were also determined, and revealed strong similarities with GST subunits from various monocotyledonous plants. Wheat GST subunits can be assigned to two groups: constitutive subunits, with identical N-termini and molecular masses around 23.2 kDa, and constitutive and inducible subunits, with some differences in N-terminal sequences, and molecular masses around 24.9 kDa.