Recombinant WT and mutant PF4 and NAP-2 proteins studied. (A) Schematic presentation of the proteins tested and the concentration (molarity) of NaCl required to elute each protein from a heparin agarose bead column. (B) Coomassie blue staining of 10 μg of various recombinant proteins separated on an SDS-PAGE gel. M, protein markers. Lane 1, WT PF4; lane 2, PF4K61A; lane 3, PF4K62A; lane 4, PF4K65A; lane 5, PF4K66A; lane 6, PPNP; lane 7, WT NAP-2; lane 8, NPPP; lane 9, NNPP; lane 10, NNNP; lane 11, NNP*P; and lane 12, WT PF4.