PURIFICATION OF RECOMBINANT INSECT TRANSFERRIN FROM LARGE VOLUMES OF CELL-CULTURE MEDIUM USING HIGH-CAPACITY NI2-DIPICOLYLAMINE GEL()

We report the purification of secreted recombinant Manduca sexta trans ferrin from Spodoptera frugiperda (Sf9) cell culture medium in a singl e step using high capacity Ni2+-dipicolylamine (DPA)-Novarose gel. Alt hough the original sample was highly diluted (similar to 10 mu g trans ferrin/ml medium) and the cell culture medium contained 10% surfactant (Pluronic F68) and a lipid emulsion, we were able to recover the reco mbinant transferrin (1 mg protein/100 mi) under gentle elution conditi ons with 70% yield at >90% homogeneity. This work demonstrates the ver satility of immobilized metal ion affinity chromatography using a high metal ion capacity gel to purify a recombinant protein and illustrate s the potential of this affinity technique for protein separations fro m large volumes of cell culture media that contain surfactants. (C) 19 96 Academic Press, Inc.