| Chondroitin sulfate Sepharose was shown to be equally efficient in retaining PF 4 from platelet extracts as serglycin Sepharose indicating that the glycosaminoglycan chains mediate the binding to PF 4 in the intact proteoglycan molecule . ^^^ Competition experiments showed that serglycin was as efficient as heparin sulfate in blocking the binding of [ 3H ] chondrotin sulfate to PF 4 , whereas heparin was one order of magnitude more efficient . ^^^ Amino terminal sequencing of two proteins from platelet extracts that bound to serglycin Sepharose revealed that they corresponded to multimeric forms of human platelet factor 4 ( PE 4 ) . ^^^ |