title: Heterodimers of glutathione S-transferase can form between isoenzyme classes pi and mu.
abstract: Glutathione S-transferases constitute a family of enzymes that detoxify xenobiotics by conjugating glutathione with a range of electrophilic substrates. The cytosolic glutathione S-transferase dimeric isoenzymes are currently divided into at least eight classes on the basis of their physical and chemical properties. Previously, heterodimers have only been detected within a given class of isoenzymes; however, here we describe for the first time the generation of a heterodimer between a pi class and mu class glutathione S-transferase. The heterodimer forms under mild conditions (dialysis against phosphate buffer, pH 6.5) and is best detected when one of the isoenzyme subunits is in excess. The activity of the pi-mu heterodimer toward several substrates indicates that interaction between these two dissimilar subunits influences the catalytic activity of this dimer. The production of this new heterodimer provides a new approach in glutathione S-transferase research to study the influence of one subunit on the catalytic activity of its partner subunit and to identify those amino acid residues which contribute to subunit interactions.
authors.affiliation: Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA.
authors.forename: N E
authors.initials: NE
authors.lastname: Pettigrew
authors.forename: R F
authors.initials: RF
authors.lastname: Colman
mesh_terms: D000818:Animals; D002384:Catalysis; D019281:Dimerization; D005982:Glutathione Transferase / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D008027:Light; D008168:Lung / Q000201:enzymology; D011485:Protein Binding; D012542:Scattering, Radiation; D013379:Substrate Specificity; D013552:Swine; D013997:Time Factors
chemical_list: D005982:Glutathione Transferase