INTERACTION BETWEEN HISTIDINE-RICH GLYCOPROTEIN AND PLATELET FACTOR-IV WITH DERMATAN SULFATE AND LOW-MOLECULAR-WEIGHT DERMATAN SULFATE

There is a controversy about whether or not histidine-rich glycoprotein (HRG), the most abundant plasma protein with glycosaminoglycans-neutralizing capacity, is able to prevent the inhibition of human thrombin by heparin cofactor II (HC II) in the presence of dermatan sulfate (DS). The authors studied the interaction of DS and low molecular weight DS, in a purified system with HRG, platelet factor 4 (PF 4), and with HC II. Their results show that HRG, like PF 4, has an affinity, not only for heparin, but also for DS. However, this affinity seems very weak. In fact, HRG is 10 times less effective than PF 4 in neutralizing the 50% antithrombin activity of HC II in the presence of DS.