Molybdate permits resolution of untransformed glucocorticoid receptors from the transformed state.

This is the authors' abstract. We don't add key points for this paper.

The presence of 10 mM sodium molybdate has a profound effect on the physical behavior of glucocorticoid receptors submitted to ammonium sulfate precipitation or to DEAE-cellulose chromatography. Molybdate inhibits the inactivation of the unoccupied receptor and prevents the transformation of the steroid-bound receptor that occurs when rat liver cytosol is precipitated with ammonium sulfate. The transformed glucocorticoid . receptor complex is precipitated at 30 to 35% ammonium sulfate, whereas the unoccupied receptor and the untransformed steroid-bound receptor are precipitated at 45 to 55% of ammonium sulfate saturation. The untransformed steroid . receptor complex precipitated at 45 to 55% ammonium sulfate saturation in the presence of molybdate can undergo temperature-mediated transformation when it is redissolved in buffer without molybdate. The presence of molybdate in both the loading buffer and eluting gradient during DEAE-cellulose chromatography prevents the transformation of steroid-bound receptor to a less negatively charged, DNA-binding state which otherwise occurs during the chromatographic procedure. In the presence of molybdate, DEAE-chromatography yields a 33-fold purification of the untransformed steroid . receptor complex.