Characterization of cytosolic glutathione S-transferases in juvenile Chinook salmon ( Oncorhynchus tshawytscha)

Four cytosolic glutathione S-transferase (GST) classes were isolated and characterized from juvenile winter run Chinook salmon ( Oncorhynchus tshawytscha) liver. Two techniques were used: (1) gel electrophoresis/immunoblotting against a polyclonal striped bass GST antibody and (2) high-pressure liquid chromatography (HPLC). Nanospray liquid chromatography–tandem mass spectrometry (LC–MS/MS) was used to elucidate peptide sequences and the proteins were identified as π, θ, μ and α, by searching against the NCBI non-redundant database (nrDB). Catalytic activity of the cytosolic GSTs towards 1-chloro-2,4-dinitrobenzene (CDNB) and ethacrynic acid (ETHA) were determined to be 0.3 ± 0.05 U/mg cytosolic protein and 0.06 ± 0.02 U/mg cytosolic protein, respectively.