All 3 MGSA/GRO proteins bind to the same receptors, but with differing affinities, and stimulate a number of biological responses including chemotaxis, angiogenesis, and growth regulation. GRO-β is a powerful chemoattractant for neutrophils, and enhances their degranulation and release of lysosomal enzymes. It also promotes the growth of fibroblasts. rHu GRO-β produced in E. coli is a single, non-glycosylated, polypeptide chain that contains 73 amino acids and has a molecular mass of 7.9 kDa.