Affinity purification of human plasma fibronectin on immobilized gelatin.

Several problems are associated with the biospecific affinity purification of plasma fibronectin on gelatin-Sepharose. Large-scale development of this purification procedure requires optimization of adsorption and elution conditions. The adsorption capacity depends on the amount of gelatin coupled to the Sepharose, the residence time, the temperature and the amount of fibronectin loaded on the adsorbent. Elution of adsorbed fibronectin with 3 M urea leads to incomplete recovery. The elution yield was found to vary with both the gelatin concentration and the amount of adsorbed fibronectin. Despite the incomplete elution, the adsorption capacity did not decrease after twelve consecutive isolation procedures. Under optimized conditions, the method described here provides a rapid, single-step and convenient way for the isolation of pure and functional fibronectin, either for analytical or large-scale preparative purposes.