Binding of human xanthine oxidase to sulphated glycosaminoglycans on the endothelial-cell surface.

摘要: Much evidence has suggested that the superoxide generated by xanthine oxidase (XOD) within endothelial cell triggers characteristic free-radical-mediated tissue injuries. Although it been reported XOD exists not only in cytoplasm, but also on outside surface of membrane, is clear how localizes plasma membrane. Purified human (h-XOD) had an affinity for heparin-Sepharose. The binding was largely independent pH over physiological range, whereas tended to increase at lower and decrease higher pH. Exposure h-XOD lysine-specific reagent trinitrobenzenesulphonic acid or arginine-specific phenylglyoxal caused lose its heparin apparently electrostatic nature, both lysine arginine residues are involved binding. found bind cultured porcine aortic cells, this inhibited addition pretreatment cells with heparinase and/or heparitinase. Intravenous injection into two healthy persons led a prompt concentration. These results suggest association polysaccharide chains heparin-like proteoglycans endothelial-cell membranes. Superoxide extracellularly may injure source-endothelial-cell membrane attract activate closely appositional neutrophils, which themselves actually cause progressive oxidative damage.