ANALYSIS AND CHARACTERIZATION OF GLUTATHIONE-S-TRANSFERASE SUBUNITS FROM WHEAT (TRITICUM-AESTIVUM L.)

The total subunit complement of glutathione S-transferases (GSTs) of w heat (Triticum aestivum L.) was isolated by glutathione-agarose affini ty chromatography. The proteins bound to the affinity column were anal ysed by SDS-PAGE, which separated six to seven protein bands. Reverse phase-HPLC analysis revealed six major and about 15 minor peaks. The a mounts of three major components were increased upon treatment with th e herbicide safener naphthalic anhydride. The six major components wer e isolated. Their relative molecular masses, determined by electrospra y ionization mass spectrometry, were between 23140 +/- 2 and 24957 +/- 3 Da. The sequences of the 20 N-terminal amino acids were also determ ined, and revealed strong similarities with GST subunits from various monocotyledonous plants. Wheat GST subunits can be assigned to two gro ups: constitutive subunits, with identical N-termini and molecular mas ses around 23.2 kDa, and constitutive and inducible subunits, with som e differences in N-terminal sequences, and molecular masses around 24. 9 kDa. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.