ENDOTOXIN LEVEL <0.1 EU per 1 μg of the protein by the LAL method. Human Recombinant GMP Grade EGF (Epidermal growth factor). Epidermal growth factor (EGF) stimulates cell growth and differentiation by binding to its receptor, EGFR. Human EGF is a 6 kDa protein with 53 amino acid residues and three intramolecular disulfide bonds. EGF is present in various body fluids, including blood, milk, urine, saliva, seminal fluid, pancreatic juice, cerebrospinal fluid, and amniotic fluid. Biological activities ascribed to EGF include epithelial development, angiogenesis, inhibition of gastric acid secretion, fibroblast proliferation, and colony formation of epidermal cells in culture.