Released during platelet aggregation. Neutralizes the anticoagulant effect of heparin because it binds more strongly to heparin than to the chondroitin-4-sulfate chains of the carrier molecule. Chemotactic for neutrophils and monocytes. Inhibits endothelial cell proliferation (By similarity). Homotetramer. Interacts with TNFAIP6 (via Link domain). Binds non-covalently to a proteoglycan molecule. Belongs to the intercrine alpha (chemokine CxC) family.