Description: Epidermal growth factor (EGF) is the member of the EGF family that shares a structural motif, the EGF-like domain, and are synthesized as type I transmembrane precursor proteins that contain several EGF domains in the extracellular region. The mouse EGF precursor has 1217 amino acid residues containing nine EGF domains. The mature protein consists of 53 aa and is generated by proteolytic excision of the EGF domain proximal to the transmembrane region resulting in a molecular mass of 6 kDa. EGF is produced by many cell types and in blood and various body fluids, including milk, urine, saliva, seminal fluid, pancreatic juice, cerebrospinal fluid, and amniotic fluid. EGF can promote proliferation and differentiation of mesenchymal and epithelial cells. EGF is also a mitogen for fibroblasts, epithelial and endothelial cells, and promotes colony formation of epiderma.