Shepherd V L, Lee Y C, Schlesinger P H, Stahl P D
Proc Natl Acad Sci U S A. 1981 Feb;78(2):1019-22. doi: 10.1073/pnas.78.2.1019.
125I-Labeled L-fucose-albumin complex and rat preputial beta-glucuronidase are rapidly cleared from plasma after intravenous infusion. L-Fucose-albumin retards the plasma clearance of beta-glucuronidase whereas D-fucose-albumin is inactive. In vitro, 125I-labeled L-fucose-albumin is taken up into rat or rabbit alveolar macrophages by receptor-mediated pinocytosis. Uptake (37 degrees C) is time-dependent, is saturable with increasing ligand concentration (Kuptake = 4.4 X 10(-8) M), and requires Ca2+. 125I-labeled D-fucose-albumin is poorly taken up. Binding (4 degrees C) is saturable and Ca2+ dependent. Binding and uptake are fully inhibited by yeast mannan. A series of neoglycoproteins, including L-fucose-albumin, were tested as inhibitors of uptake of 125I-labeled beta-glucuronidase into macrophages. The following order of potency was observed: L-Fuc = D-Man greater than GlcNAc approximately D-Glc greater than D-Xyl much greater than than D-Gal = L-Ara = D-Fuc. L-Fucose-terminated oligosaccharides coupled to bovine serum albumin also block 125I-labeled beta-glucuronidase uptake into macrophages.
静脉注射后，125I标记的L-岩藻糖-白蛋白复合物和大鼠包皮β-葡萄糖醛酸酶可迅速从血浆中清除。L-岩藻糖-白蛋白可延缓β-葡萄糖醛酸酶的血浆清除，而D-岩藻糖-白蛋白则无此作用。在体外，125I标记的L-岩藻糖-白蛋白通过受体介导的胞饮作用被大鼠或兔肺泡巨噬细胞摄取。摄取（37℃）具有时间依赖性，随着配体浓度增加可饱和（摄取常数Kuptake = 4.4×10(-8) M），且需要Ca2+。125I标记的D-岩藻糖-白蛋白摄取较差。结合（4℃）具有饱和性且依赖Ca2+。结合和摄取均被酵母甘露聚糖完全抑制。测试了一系列包括L-岩藻糖-白蛋白在内的新糖蛋白作为125I标记的β-葡萄糖醛酸酶摄取到巨噬细胞中的抑制剂。观察到以下效力顺序：L-岩藻糖 = D-甘露糖＞N-乙酰葡糖胺≈D-葡萄糖＞D-木糖＞＞D-半乳糖 = L-阿拉伯糖 = D-岩藻糖。与牛血清白蛋白偶联的L-岩藻糖末端寡糖也可阻断125I标记的β-葡萄糖醛酸酶摄取到巨噬细胞中。
