Fibroblast Growth Factor 2 (FGF-2) is expressed by endothelial cells and is a mediator of angiogenesis. FGF-2 also has cardioprotective functions during heart injury. The application of FGF-2 is a critical component for embryonic stem cell culture systems and is necessary for maintaining cells in an undifferentiated state. Degredation of the full length FGF-2 N-terminus results in a truncated FGF-2 147 amino acids protein, when the protein is isolated from biological sources. The N-terminus extensions influence the localization of FGF-2 within the cell, but do not affect the biological activity of FGF-2. Therefore, there are no detectable differences in biological activity between the full length FGF-2 154 amino acids and the truncated FGF-2 147 amino acids recombinant proteins.