Purification of two distinct growth factors from bovine neural tissue by heparin affinity chromatography

Two growth factors have been purified to homogeneity from either bovine hypothalamus or brain by heparin affinity chromatography. Both stimulate the growth of murine 3T3 fibroblasts and bovine capillary endothelial cells. One heparin-binding growth factor (HGF alpha), purified from either tissue by elution from heparin with 1.0 M sodium chloride, is obtained in a yield of 0.4 mg/kg of tissue. Its apparent molecular weight is 16 000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and its amino acid composition is identical with that of the acidic fibroblast growth factor recently isolated from bovine brain by a multistep chromatographic procedure Thomas, K. A., Rios-Candelore, M., & Fitzpatrick M. (1984) Proc. Natl. Acad. Sci. U.S.A. 81, 357-361. A second growth factor (HGF beta), isolated from either tissue by elution from heparin with 2.0 M sodium chloride, is obtained in a yield of 0.02 mg/kg of tissue. Its apparent molecular weight is 18 000 by SDS-PAGE, and its amino acid composition differs from that of HGF alpha. These results confirm the existence of two distinct growth factors in bovine neural tissue and establish that the acidic endothelial cell growth factor from hypothalamus and the acidic brain fibroblast growth factor are identical.