In the circulation, most of the insulin-like growth factors (IGFs) are bound to a ternary 150 kDa complex with IGF-binding protein (IGFBP)-3 and the acid labile subunit. In the current study, we identify transferrin (Tf) by mass spectrometry, and immunoprecipitation as a component of a major IGF-binding fraction separated from human plasma. IGF ligand blotting, cross-linkage experiments and surface plasmon resonance spectrometry have been used to demonstrate the capability of Tf to bind IGFs specifically. In combination with Tf, IGFBP-3 showed a 5-fold higher affinity for IGF-II than IGFBP-3 alone. The data suggest that Tf may play an important role in regulating IGF/IGFBP-3 functions. © 2001 Federation of European Biochemical Societies. Published by Elsevier Science B.V. All rights reserved.
Storch, S., Kübler, B., Höning, S., Ackmann, M., Zapf, J., Blum, W., & Braulke, T. (2001). Transferrin binds insulin-like growth factors and affects binding properties of insulin-like growth factor binding protein-3. FEBS Letters, 509(3), 395–398. https://doi.org/10.1016/S0014-5793(01)03204-5