Expression of soluble VEGF receptor 2 and characterization of its binding by surface plasmon resonance

Vascular endothelial growth factor (VEGF) is an endothelial cell specific m itogen that induces angiogenesis in several pathological conditions, To blo ck angiogenesis, soluble VEGF receptor can be used. In this study, we descr ibe a method for high yield expression of soluble VEGF receptor 2 (sFlk-1) in a baculovirus expression system (30 mg purified sFlk-1 per L of insect c ell supernatant), We also determined the binding constants for both human a nd mouse VEGF to the recombinant receptor by surface plasmon resonance. In this cell-free assay, under the given experimental conditions, the on-rate k(a) was 0.5-2.2 x 10(6) M(-1)s(-1) and the off-rate k(d) was 2-4 x 10(-4) s(-1) (K-D = 2-6 x 10(-10) M), To our knowledge this is the first study to report on- and off-rates for the VEGF:sFlk-1 interaction. Heparin was not r equired for the binding of VEGF to sFlk-1 in this assay, The obtained value s will serve as baseline parameters for the design of improved versions of recombinant soluble VEGF receptor, (C) 1998 Academic Press.