Characterization of testosterone binding protein of rat liver cytosol

Testosterone binding protein from rat liver cytosol, which had been incubated with [3H]testosterone followed by treatment with dextran-coated charcoal, was analyzed by DEAE-cellulose and phosphocellulose chromatography. On DEAE-cellulose chromatography, two distinct peaks of radioactivity were eluted at 0.07 M and 0.19 M KCl, both sedimented in 4 S regions. Phosphocellulose chromatography resulted in a broad peak at 0.08 M KCl, with a shoulder at 0.04 M KCl, both sedimented at 4 S. These findings indicated that testosterone binding protein consists of two types of components each with 4 S.