Application of high-performance ion-exchange chromatography to the analysis of cytosolic glucocorticoid receptor.

The use of high-performance ion-exchange chromatography (HPIEC) on a Mono Q column was investigated for the analysis of glucocorticoid receptor. In the presence of 10 mM sodium molybdate, both liganded and unliganded glucocorticoid receptor were eluted as a single and sharp peak (0.32 M NaCl). In the absence of molybdate and after exposure to heat and salt, another peak of specifically bound radioactivity was eluted with 0.08 M NaCl. When HPIEC was performed in the absence of molybdate, two molecular forms of the liganded receptor were detected which eluted with 0.08 M NaCl (Stokes' radius Rs = 5.1 nm, s20,w = 4.6 S, calculated mol. wt Mr approximately 100,000) and 0.32 M NaCl (Rs = 7.3 nm, S20,w = 9.0 S, calculated Mr approximately 280,000). Analysis of both forms with mini-columns of DNA-Ultrogel, DEAE-Trisacryl and hydroxylapatite (HA-Ultrogel) confirmed the identity of the two peaks with transformed and non-transformed glucocorticoid-receptor complexes. These results suggest that HPIEC may provide a useful tool for the rapid resolution and quantification of receptor molecular forms.