Purification of a chick brain-derived growth factor by reversed-phase high-performance liquid chromatography.

A chick brain-derived growth factor (CBGF) has been purified to apparent homogeneity by a combination of ultrafiltration, DEAE ion-exchange, and reversed-phase high-performance liquid chromatography on a C18 column. CBGF has an apparent molecular mass of approximately 1500 Da. The amino acid composition of CBGF has been determined and reveals a peptide containing predominantly glycine, glutamic acid/glutamine, and aspartic acid/asparagine. This mitogen is highly active, with half-maximal stimulation of chick brain astrocytes at 5 ng/ml in an assay using incorporation of methyl-3H-thymidine into DNA. In addition to its effects on chick astrocytes, purified CBGF from the 18 d chick embryo is mitogenic for amphibian limb regeneration blastema cells in vitro. A possible role for this mitogen in the nerve-dependent regeneration of amphibian appendages is discussed.