SYNTHESIS AND BIOLOGICAL-ACTIVITY OF N-TERMINAL-TRUNCATED DERIVATIVESOF HUMAN EPIDERMAL GROWTH-FACTOR (H-EGF)

To investigate the contribution of the N-terminal sequence of h-EGF to its biological activity and the formation of three intramolecular dis ulfide bonds by oxidative refolding via air oxidation, five derivative s of h-EGF with a single N-terminal amino acid deletion were synthesiz ed by solid-phase synthesis. The homogeneity of the synthetic peptides was confirmed by analytical reversed-phase HPLC, amino acid analysis, and FAB-MS. The pairing of the three disulfide bridges in synthetic p eptides was determined by thermolytic digestion. All N-truncated deriv atives of h-EGF formed the correct intramolecular three disulfide link ages during oxidative refolding and had equipotent activity in both EG F receptor binding on A-431 epidermoid carcinoma cells and mitogenesis on NIH-3T3 fibroblast cells, compared with authentic h-EGF. The resul ts suggested that the five residues from N-terminal sequence of h-EGF have no effect on the formation of the correct disulfide linkages in h -EGF and do not exert a significant influence on its biological activi ty.