Bio-activity
Measured by its binding ability in a functional ELISA. 1 μg/mL of rhFGF-BP was mixed with serially diluted rhFGF basic. Following incubation, the FGFBP-FGF basic complex was captured on a Gt x hFGFBP-coated plate. Bound FGF basic was measured using biotinylated Gt x hFGF basic. The concentration of rhFGF basic that produces 50% of the optimal binding was found to be approximately 5-20 ng/mL.