Purity >95% as determined by SDS-PAGE. Fibroblast growth factor 4 (FGF4) is a secreted growth factor that is predominantly expressed during bone morphogenesis and embryonic limb development. FGF4 is an important growth regulator for stem cells, fibroblasts, and endothelial cells. FGF4 contains a single N-linked glycosylation signal. However, in-vitro studies suggest that unglycosylated FGF4 is cleaved into 13 kDa and 15 kDa truncated proteins that have greater biological activity than the wild type 19 kDa FGF4 protein. Human FGF4 shares high homology and is cross-reactive with mouse FGF4.