Application of preparative reversed-phase high-performance liquid chromatography to the isolation of insulin-like growth factor II from human serum

Substantially purified insulin-like growth factor II (IGF-II) was prepared from human serum. Initial enrichment using ion-exchange chromatography on DEAE Sephadex A50, followed by gel permeation chromatography on Sephadex G-75 in 1% formic acid produced material suitable for application to a preparative reversed-phase high-performance liquid chromatographic (HPLC) column containing LiChroprep RP-18. The latter step gave about 90-fold purification with a recovery of about 70% IGF-II bio-activity. Finally, a small reversed-phase HPLC column achieved a 17-fold purification with similar yield of activity. Overall, the four steps gave IGF-II of about 90% purity in yield of 12%.