Biosensor measurement of the interaction kinetics between insulin-like growth factors and their binding proteins.

摘要: Abstract The binding kinetics of human insulin-like growth factor protein (IGFBP) 1–6 for recombinant (IGF) I and II were measured compared in the present study using surface plasmon resonance biosensor technique. Different concentrations IGFBPs (5–100 nM) allowed to interact with immobilized IGF-I or IGF-II on sensor chip surface. Both des(1–3)IGF-I insulin are known bind weakly therefore used as negative controls experiments. resultant sensorgrams analyzed by simple 1:1 model derive both association rate ( k a ) dissociation d constants IGFBP–IGF interactions. values range 1×10 4 9×10 5 M −1 s 7×10 3 1.7×10 6 IGF-II, respectively. orders IGFBP-3>IGFBP-5>IGFBP-6>IGFBP-4>IGFBP-2>IGFBP-1. 1.5×10 −5 2×10 −4 3.6×10 3.7×10 order is IGFBP-6>IGFBP-5>IGFBP-4>IGFBP-3>IGFBP-2>IGFBP-1 that IGFBP-5>IGFBP-6>IGFBP-2>IGFBP-4>IGFBP-3>IGFBP-1, equilibrium affinity K A calculated based ratio / more precise than published literature competitive radioligand assays. systematic enables direct comparison IGF-binding properties among various IGFBPs, kinetic data provide additional information delineate physiological role different vivo.