[Isolation and characterization of 11-S-globulins from sunflower seeds (Helianthus annuus L.)]

The isolation of II-S globulin, which is homogenous on sedimentation and gel chromatography (s020, w = II,8 S), from sunflower seeds is achieved by cryoprecipitation from solutions of high ion strength (I approximately 0.5 to 1.8) with simultaneous reduction of the salt concentration (I approximately 0.3) and repeated gel chromatography on Sephadex G-200. By this technique, the 7-S component which occurs in small quantity is isolated too. In solutions of low ion strength (I less than 0,3), the II-S globulin dissociates to give a 7-S component. At high or low pH values (greater than 9.0 and less than 3.0, respectively), the latter dissociates to give a 3-S component, and in the presence of urea it further dissociates to give subunits. In the presence of sodium of sodium chloride, the dissociation of the 3-S component may be inhibited. The various steps of dissociation can be studied by means of ultracentrifugal sedimentation, gel chromatography and gel electrophoresis.