Purified appetite-regulating substances of biological orgin, their

Abstract

The selective appetite-regulating substances satietin and satietin-D had up to the present been prepared from human or animal blood serum or plasma by ultrafiltration, gel chromatography, treatment with trichloroacetic acid, affinity chromatography and optionally treatment with a proteolytic enzyme. According to the invention, satietin and satietin-D are obtained in a purified form by using immunoabsorption. Being glycoproteins, both satietin and satietin-D form antibodies (antisatietin and antisatietin-D, respectively) in the living organism and can be isolated from the blood and bound to a gel column. For the preparation of satietin and satietin-D, respectively, the human or animal blood plasma or serum is subjected to ultrafiltration and the ultrafiltrate, containing in addition to satietin and satietin-D other constituents with a molecular weight below 50000 daltons, is contacted with the gel column. The antibody bound to the gel column forms with satietin or satietin-D, respectively, an immunocomplex remaining on the column while the other constituents of the ultrafiltrate can be eluted by a buffer. Then, the immunocomplex is cleaved, whereby satietin or satietin-D, respectively, can be eluted in a purified form from the column. The column containing the antibody may repeatedly be used.