Purification of the fibroblast growth factor activity from bovine brain

The purification of the fibroblast growth factor (FGF) from bovine brain has led to the isolation of two peptides. FGF-1 with 128 amino acids and FGF-2 with 107 amino acids. The biological activity of these two peptides is acid- and heat-labile. As indicated by the amino acid composition of FGF-1 and -2, these two peptides are derived from a common precursor and bear no resemblance to pituitary FGF. The brain FGF peptides, like pituitary FGF, are mitogenic in vitro for the same wide variety of mesoderm-derived cells. Since their mitogenic activity is acid- and heat-labile, they are thereby distinguished from the platelet factor isolated from platelets and from the cationic peptide isolated from serum which has been shown to have the same molecular weight and isoelectric point as brain and pituitary FGF.