Preparation of electrophoretic variants of Corticosteroid-binding Globulin (CBG) using liquid liquid partition chromatography ☆

Abstract Human corticosteroid-binding globulin (CBG) was purified to homogeneity by application of three different chromatographic methods. After fractionation of pregnancy serum with ammonium sulfate the 80%-pellet was used for affinity chromatography based on tresyl activated Sepharose (Pharmacia, Uppsala, Sweden). The affinity eluate was injected into a Mono Q anion exchange column (Pharmacia). Fractions containing CBG were finally purified by liquid liquid chromatography on LiParGel 750 (Merck, Darmstadt, F.R.G.) 1,2 . The purified protein was characterized by IEF and PAGE. This paper describes a method for the chromatographic separation of the two variants of CBG without a loss of binding activity towards steroids for each of the two characteristic bands of this protein.