Purity >95% as determined by SDS-PAGE. Growth regulated protein beta (GRO-beta), also known as CXCL2, is a chemokine that is secreted by macrophages, neutrophils, and monocytes at sites of inflammation. GRO-beta functions as a chemoattractant for leukocytes and hematopoietic stem cells. GRO-beta activity is mediated through binding the G-protein-coupled chemokine receptor CXCR2.