The single cysteine residue on an alpha family chick liver glutathione S-transferase CL 3-3 is not functionally important.
Chick liver glutathione S-transferase CL 3-3, expressed using a baculovirus system in Spodoptera frugiperda (SF9) cells, contains a single cysteine residue per subunit. This enzyme was modified with iodoacetamide. Amino acid analysis indicates that 0.85 +/- 0.10 cysteine residue was modified per enzyme subunit. GST CL 3-3 modified with iodo[14C]acetamide was further digested with trypsin and the isotope-labelled fragments were isolated. The fragment containing the cysteine residue accounts for 53% of the total labels. The S-carbaminomethylated protein retains the glutathione conjugating activity. Therefore, the cysteine residue is not essential for the enzymatic activity of CL 3-3.
Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China.
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D000595:Amino Acid Sequence; D000818:Animals; D002645:Chickens; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000737:chemistry*; D015870:Gene Expression; D005982:Glutathione Transferase / Q000737:chemistry* / Q000187:drug effects / Q000235:genetics; D007460:Iodoacetamide / Q000494:pharmacology; D008099:Liver / Q000201:enzymology*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000032:analysis; D011994:Recombinant Proteins / Q000737:chemistry / Q000187:drug effects; D013329:Structure-Activity Relationship; D013379:Substrate Specificity
D010446:Peptide Fragments; D011994:Recombinant Proteins; D005982:Glutathione Transferase; D003545:Cysteine; D007460:Iodoacetamide