Probing subunit interactions in glutathione S-transferases using affinity labeling

Roberta F. Colman, Joseph J. Barycki, Melissa A. Vargo, Jibo Wang

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Affinity labeling, using reactive analogs of natural ligands, provides a powerful approach to probe for the existence of cooperative interactions between subunits as well as to locate specific xenobiotic binding sites in glutathione 5-transferases (GST). Thus, 3β-(iodoacetoxy)-dehydroisoandrosterone (3β-IDA) and 17-(iodoacetoxy)estradiol-3-sulfate (17β-IES) function as affinity labels of the nonsubstrate steroid binding site of rat liver GST, isozyme 1-1. Modification of Cys17 or Cys111 on Subunit A prevents reaction of the same cysteine on Subunit B. Interactions between the subunits of both the 4-4 and 1-1 isozymes are also illustrated by photoaffinity labeling of the active sites of these homodimers by glutathionyl S[4-(succinimidyl)-benzophenone], an analog of the product of glutathione and xenobiotic substrate.

Original languageEnglish (US)
Pages (from-to)159-162
Number of pages4
JournalChemico-Biological Interactions
Issue number1-3
StatePublished - Feb 28 2001
Externally publishedYes


  • Affinity labeling
  • Glutathione S-transferase
  • Subunit interaction

ASJC Scopus subject areas

  • Toxicology


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