Purification of two dexamethasone-binding proteins from rat-liver cytosol.
Two dexamethasone-binding proteins have been purified from rat liver cytosol. The main purification steps are: precipitation by protamine sulphate, affinity chromatography on CH-Sepharose 4B to which 11-deoxycorticosterone is linked through a disulfide bond and DEAE-cellulose chromatography. Two binding components elute from the DEAE-cellulose column at 0.12 M and 0.2 M NaCl, respectively. By means of dodecylsulphate/polyacrylamide gel electrophoresis it was demonstrated that both components are composed predominantly of a single polypeptide with molecular weights of about 45 000 and 90 000. Antibodies to the two polypeptides have been elicited in rabbits. The antibodies to the 45 000-Mr polypeptide cross react with the 90 000-Mr component. Likewise the antibodies to the 90 000-Mr protein precipitate the 45 000-Mr polypeptide. Either of the two antibody preparations immunoprecipitates the major part (approximately 70%) of the dexamethasone-binding activity of the cytosol.
D000818:Animals; D002846:Chromatography, Affinity; D003600:Cytosol / Q000378:metabolism; D003907:Dexamethasone / Q000378:metabolism*; D005779:Immunodiffusion; D008099:Liver / Q000378:metabolism*; D008970:Molecular Weight; D011233:Precipitin Tests; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000276:immunology / Q000302:isolation & purification*; D011987:Receptors, Steroid / Q000302:isolation & purification*
D011965:Receptors, Glucocorticoid; D011987:Receptors, Steroid; D003907:Dexamethasone