Chuang Wei-Lien, McAllister Heather, Rabenstein Dallas L
Department of Chemistry, University of California, Riverside, CA 92521, USA.
Carbohydr Res. 2002 May 13;337(10):935-45. doi: 10.1016/s0008-6215(02)00050-2.
Specific sequences in heparin are responsible for its modulation of the biological activity of proteins. As part of a program to characterize heparin-peptide and heparin-protein binding, we are studying the interaction of chemically discrete heparin-derived oligosaccharides with peptides and proteins. We report here the isolation and characterization, by one- and two-dimensional 1H NMR spectroscopies, of ten hexasaccharides, one pentasaccharide, and one octasaccharide serine that were isolated from depolymerized porcine intestinal mucosal heparin. Hexasaccharides were chosen for study because they fall within the size range, typically tetra- to decasaccharide in length, of heparin sequences that modulate the activity of proteins. The depolymerization reaction was catalyzed by heparinase I (EC 4.2.2.7) in the presence of histamine, which binds site specifically to heparin. Histamine increases both the rate and extent of heparinase I-catalyzed depolymerization of heparin. It is proposed that oligosaccharides produced by heparinase I-catalyzed depolymerization can inhibit the enzyme by binding to the imidazolium group of histidine-203, which together with cysteine-135 forms the catalytic domain of heparinase I. The increased rate and extent of depolymerization are attributed to competitive binding of the oligosaccharides by histamine.
肝素中的特定序列决定了其对蛋白质生物活性的调节作用。作为肝素 - 肽和肝素 - 蛋白质结合特性研究计划的一部分，我们正在研究化学性质明确的肝素衍生寡糖与肽和蛋白质之间的相互作用。在此，我们报告通过一维和二维¹H NMR光谱法从猪肠黏膜肝素解聚产物中分离并鉴定出的十种六糖、一种五糖和一种八糖丝氨酸。选择六糖进行研究是因为它们的大小范围（通常为四糖至十糖）属于调节蛋白质活性的肝素序列范围。解聚反应由肝素酶I（EC 4.2.2.7）在组胺存在下催化，组胺可特异性结合肝素位点。组胺可提高肝素酶I催化肝素解聚的速率和程度。据推测，肝素酶I催化解聚产生的寡糖可通过与组氨酸 - 203的咪唑鎓基团结合来抑制该酶，组氨酸 - 203与半胱氨酸 - 135共同构成肝素酶I的催化结构域。解聚速率和程度的提高归因于组胺对寡糖的竞争性结合。
