Characterization of human platelet GMP-140 as a heparin-binding protein

Human platelet GMP-140 has been identified as a heparin-binding protein. Purified platelet GMP-140 bound to Heparin-Sepharose CL-6B and was eluted by ∼0.5 M sodium chloride. Radioiodinated GMP-140 bound specifically and saturably to heparin immobilized on Matrex-Pel 102 beads. Binding of radioiodinated GMP-140 to heparin-Matrex-Pel 102 beads was divalent cation-independent and was strongly inhibited by excess fluid phase GMP-140 and heparin and by other sulfated glycans such as fucoidin and dextran-sulfate. Binding was not inhibited by chondroitins 4- and 6-sulfate or mannose 6-phosphate.