Purification and Characterization of Glutathione Transferases from the Sea Bass (Dicentrarchus labrax) Liver

• Published in: Archives of biochemistry and biophysics Vol. 373; no. 2; pp. 435 - 441
• Main Authors: Angelucci, Stefania, Sacchetta, Paolo, Moio, Pasquale, Melino, Sonia, Petruzzelli, Raffaele, Gervasi, PierGiovanni, Di Ilio, Carmine
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.01.2000
• Subjects: Amino Acid Sequence; Animals; Bass - metabolism; Chromatography, High Pressure Liquid; Circular Dichroism; Electrophoresis, Polyacrylamide Gel; fish; Glutathione Transferase - chemistry; Glutathione Transferase - classification; GSH transferase; Isoelectric Focusing; Isoenzymes - chemistry; liver; Liver - enzymology; Mediterranean Sea; Molecular Sequence Data; Naphthalenesulfonates - metabolism; Protein Binding; sea bass; Sequence Analysis; Sequence Homology, Amino Acid; Substrate Specificity; xenobiotics; Mediterranean Sea; GSH transferase; sea bass; liver; xenobiotics; fish
• ISSN: 0003-9861; 1096-0384
• DOI: 10.1006/abbi.1999.1569

Two forms of glutathione transferase were purified from liver cytosol of the sea bass (Dicentrarchus labrax) by GSH–Sepharose affinity chromatography followed by chromatofocusing. The major enzyme (DL-GST-6.7; 75% of total activity bound to the column) has a pI value of 6.7 and is composed of two subunits of apparent molecular mass 26.5 kDa. The minor enzyme (DL-GST-8.2; 25% of total activity bound to the column) has a pI value of 8.2 and is composed of two subunits of molecular mass 23.5 kDa. Both isoenzymes appear to have blocked N-terminal. The purified proteins were characterized with respect to substrate specificity, CD spectra, TNS binding properties (with 2-toluidinylnaphthalene 6-sulfonate), and immunological reactivity. Partial internal amino acid sequence was also determined for each isoenzyme. The results obtained suggest that DL-GST-6.7 and DL-GST8.2 are novel GSTs belonging, respectively, to theta and alpha classes.