A tryptic digestion fragment of nerve growth factor with nerve growth promoting activity

A peptide, isolated from the acid-insoluble portion of a tryptic digest of cyanogen bromide cleaved nerve growth factor, favors life maintenance of sensory target cells and promotes rapid neurite outgrowth from 7-day-old chick embryo sensory ganglia. The fragment has been identified as a 30 amino acid peptide consisting of two linear oligopeptides linked by a disulphide bridge and corresponding to residues 10-25 and 75-88 of the amino acid sequence of nerve growth factor. On a molar basis the fragment is about 100 times more effective than intact nerve growth factor. Other peptides isolated from the digest are biologically inactive.