Shimada K, Kawamoto A, Matsubayashi K, Ozawa T
Department of Medicine and Geriatrics, Kochi Medical School, Japan.
Blood. 1989 Jan;73(1):191-3.
The role of histidine-rich glycoprotein in controlling heparin-like compounds on the endothelial cell surface is still unclear. The effects of this heparin-neutralizing protein on the interaction between antithrombin III and cultured porcine aortic endothelial cells were examined. Displacement of 125I-labeled antithrombin III specifically bound to endothelial cells by unlabeled histidine-rich glycoprotein was much less potent than that by unlabeled antithrombin III. One hundred-fold molar excess of histidine-rich glycoprotein displaced specific 125I-antithrombin III binding only by 20%. Furthermore, the endothelial cell-mediated acceleration of thrombin inactivation by antithrombin III was diminished by protamine sulfate, but was not affected by histidine-rich glycoprotein even at a histidine-rich glycoprotein/antithrombin III molar ratio of approximately 7:1. These data indicate that histidine-rich glycoprotein does not interfere with the interaction of endothelial cell heparin-like compounds with antithrombin III. Thus, it may not play an important role in the modulation of anticoagulant activity of endothelial cells in vivo, suggesting that the commonly accepted view of the probable function of this protein is erroneous.
富含组氨酸糖蛋白在控制内皮细胞表面类肝素化合物方面的作用仍不清楚。研究了这种肝素中和蛋白对抗凝血酶III与培养的猪主动脉内皮细胞之间相互作用的影响。未标记的富含组氨酸糖蛋白取代特异性结合在内皮细胞上的125I标记抗凝血酶III的能力，远不如未标记的抗凝血酶III。100倍摩尔过量的富含组氨酸糖蛋白仅使特异性125I-抗凝血酶III结合位移20%。此外，硫酸鱼精蛋白可减弱内皮细胞介导的抗凝血酶III对凝血酶失活的加速作用，但即使富含组氨酸糖蛋白与抗凝血酶III的摩尔比约为7:1，富含组氨酸糖蛋白也不会对其产生影响。这些数据表明，富含组氨酸糖蛋白不会干扰内皮细胞类肝素化合物与抗凝血酶III的相互作用。因此，它可能在体内调节内皮细胞抗凝活性方面不起重要作用，这表明关于该蛋白可能功能的普遍接受观点是错误的。
