Identification of Yb-glutathione-S-transferase as a major rat liver protein labeled with dexamethasone 21-methanesulfonate.
Dexamethasone 21-methanesulfonate, an affinity label for glucocorticoid-binding proteins, was incubated with rat liver cytosol preparations. The predominant covalently labeled component was identified as Yb-glutathione-S-transferase on the basis of chromatographic properties, electrophoretic mobility, and specific retention by an anti-Yb-immunoadsorbent. Affinity labeling of this protein was blocked by excess dexamethasone. Preferential reactivity of dexamethasone 21-methanesulfonate with the Yb subclass of glutathione-S-transferase (glutathione transferase, EC 2.5.1.18) was also evident with mixtures containing the multiple forms of the enzyme. Yb-glutathione-S-transferase, the nonsaturable glucocorticoid-binding component of rat liver cytosol should, therefore, be reclassified; because of its high concentration and selective interaction with steroids, this enzyme may be an intracellular glucocorticoid-binding protein and, thereby, influence transport, metabolism, and action of the steroids.
D000345:Affinity Labels; D000818:Animals; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000378:metabolism*; D003600:Cytosol / Q000201:enzymology; D003907:Dexamethasone / Q000031:analogs & derivatives* / Q000378:metabolism; D005938:Glucocorticoids / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism*; D008099:Liver / Q000201:enzymology*; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011965:Receptors, Glucocorticoid / Q000378:metabolism
D000345:Affinity Labels; D002352:Carrier Proteins; D005938:Glucocorticoids; D011965:Receptors, Glucocorticoid; D003907:Dexamethasone; D005982:Glutathione Transferase; C031710:dexamethasone 21-methanesulfonate