ACTIVATION OF FIBROBLAST GROWTH-FACTOR (FGF) RECEPTORS BY RECOMBINANTHUMAN FGF-5

We have purified biologically active recombinant human fibroblast grow th factor 5 (FGF-5) from Escherichia coli. In the presence of heparin, recombinant FGF-5 is as active as native growth factor, demonstrating that glycosylation does not significantly potentiate FGF-5 activity. FGF-5 can bind and induce autophosphorylation of human FGF receptors ( FGFR) 1 and 2. Competition binding studies show that the K(D) for FGF- 5-FGFR-1 and FGF-5-FGFR-2 interactions are both between 0.5 and 1.5 x 10(-9) M.