Purification and characterization of insulin-like growth factor II (IGF II) and an IGF II variant from human placenta.
In order to purify variant IGF II peptides from human placenta, we have developed a purification procedure combining heparin affinity chromatography and cation-exchange, reversed-phase and size-exclusion HPLC. Two peptides were purified, both having apparent M(r) values of ca. 7300 Da as evaluated by SDS-PAGE. N-Terminal sequencing revealed IGF II and an IGF II variant in which Ser29 was replaced by the tetrapeptide Arg-Leu-Pro-Gly. The final yield of variant IGF II was about eight-fold lower than that of IGF II. Both pure peptides were functionally active as they bound to type I and type II IGF receptors from ovine and human placental membranes, as determined by crosslinking experiments and displacement curve studies.
De Ceuninck
F
F
Institut National de la Santé et de la Recherche Médicale, Paris, France.
Willeput
J
J
Corvol
M
M
D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D003432:Cross-Linking Reagents; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000302:isolation & purification; D007335:Insulin-Like Growth Factor II / Q000235:genetics / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D010920:Placenta / Q000737:chemistry*; D011247:Pregnancy; D013552:Swine
D003432:Cross-Linking Reagents; D007334:Insulin-Like Growth Factor I; D007335:Insulin-Like Growth Factor II