The primary structure of epidermal growth factor.

The complete amino acid sequence of epidermal growth factor (EGF) has been established through the use of automated Edman degradation and standard enzymatic and chemical techniques. The location of the half-cystinyl residues was facilitated by the use of the S-[14C]aminoethyl derivative of EGF. The sequence is: NH2-Asn-Ser-Tyr-ProGly5-Cys-Pro-Ser-Ser-Tyr1o-Asp-Gly-Tyr-Cys-Leu15-AsnGly-Gly-Val-Cys20-Met-His-Ile-Glu-Ser25-Leu-Asp-Ser-TyrThr3°-Cys-Asn-Cys-Va1-Ile35Gly-Tyr Ser Gly-As~~~-ArgCys-Gin-Thr-Arg4”-AspLeuArg-TrpTrpjOGlu Leu -ArgCOOH. The calculated molecular weight of the 53-residue polypeptide is 6045, a value that is in agreement with the molecular weight of 6400 established by physical measurements. The peptide is acidic and the 6 half-cystines exist in disulfide linkage. Four arginine residues are located in the COOH-terminal portion of the molecule. The six COOHterminal amino acids are not necessary for biological activity and EGFl+ has activity identical with that of the 53-residue native molecule.