| Epidermal growth factor (EGF) is a small mitogenic polypeptide of approximately 6 kDa found in various mammalian species and distributed widely across numerous tissues and body fluids. Its activity is mediated through four ErbB (HER) family receptor tyrosine kinases: EGFR/ErbB1, ErbB2, ErbB3, and ErbB4, which respond to various members of the EGF family. While human and mouse EGFs share high similarity in their physical and chemical properties, they are not identical. Each polypeptide consists of 53 amino acid residues, with 37 residues common to both molecules and three disulfide bonds formed in identical positions. |
