Characterization of a glutathione S-transferase and a related glutathione-binding protein from gill of the blue mussel, Mytilus edulis.
The major isoenzyme of glutathione S-transferase (GST 1) was purified to homogeneity from cytosolic extracts of Mytilus edulis gill tissue by GSH-agarose affinity chromatography followed by Mono Q ion-exchange f.p.l.c. This enzyme was particularly active with 1-chloro-2,4-dinitrobenzene, ethacrynic acid and cumene hydroperoxide as substrates. Immunoblotting and amino acid sequencing studies indicate that the enzyme belongs to the Pi class of GSTs. A related protein which binds to GSH-agarose was also purified. This GSH-binding protein did not immunoblot with GST antisera and showed no detectable catalytic activity with GST substrates although its N-terminal sequence was similar to Mu-class GSTs. Gel-filtration chromatography indicated that GST 1 is a dimer and the GSH-binding protein a monomer. Mass spectrometry and SDS/PAGE indicate subunit molecular masses of 24 kDa (GST 1) and 25 kDa (GSH-binding protein), respectively. Both proteins have amino acid compositions typical of GSTs.
Fitzpatrick
P J
PJ
Department of Biochemistry, University College Cork, Ireland.
Krag
T O
TO
Højrup
P
P
Sheehan
D
D
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D049872:Bivalvia / Q000201:enzymology*; D002851:Chromatography, High Pressure Liquid; D005880:Gills / Q000201:enzymology*; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D015151:Immunoblotting; D007527:Isoenzymes / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D007700:Kinetics; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D011485:Protein Binding; D012685:Sepharose; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D000596:Amino Acids; D007527:Isoenzymes; D046911:Macromolecular Substances; D012685:Sepharose; D005982:Glutathione Transferase; D005978:Glutathione