Sakiyama T, Kabayama M, Tomita M, Nakamura J, Mukai H, Tomita Y, Furukawa K
Department of Biosignal Research, Tokyo Metropolitan Institute of Gerontology, Itabashi-ku, Tokyo 173, Japan.
Biochim Biophys Acta. 1998 Apr 10;1380(2):268-74. doi: 10.1016/s0304-4165(97)00151-7.
Only a small number of glycoproteins has been reported to contain N-linked sugar chains with GalNAcbeta1-->4GlcNAc structure. Our previous studies showed that most glycoproteins from bovine milk fat globule membranes contain beta-N-acetylgalactosaminylated N-linked sugar chains [Sato et al., J. Biochem. 114 (1993) 890-900]. In order to study how widely this glycosylation occurs, lectin blot analysis of membrane glycoproteins from 12 bovine tissues was performed using Wistaria floribunda agglutinin (WFA), which interacts with oligosaccharides terminating with N-acetylgalactosamine. The WFA-positive bands were detected in samples from most tissues except for intestine although the number and reactivity of bands to lectin varied among the tissues. Upon pretreatment of blotted filters with Bacillus beta-N-acetylgalactosaminidase or N-glycanase, no lectin binding was observed. WFA-agarose column chromatography of oligosaccharides released by hydrazinolysis from membrane glycoproteins of bovine tissues except for intestine revealed that a few to 18% of the released oligosaccharides bind and are eluted from the column with 100 mM N-acetylgalactosamine. These results indicate that many glycoproteins from a variety of bovine tissues contain N-linked sugar chains with GalNAcbeta1-->4GlcNAc structure, suggesting a wider occurrence of this glycosylation in bovine tissues.
据报道，只有少数糖蛋白含有具有GalNAcbeta1-->4GlcNAc结构的N-连接糖链。我们之前的研究表明，牛乳脂肪球膜中的大多数糖蛋白都含有β-N-乙酰半乳糖胺化的N-连接糖链[Sato等人，《生物化学杂志》114 (1993) 890-900]。为了研究这种糖基化的广泛程度，使用与以N-乙酰半乳糖胺结尾的寡糖相互作用的紫藤凝集素（WFA）对12种牛组织的膜糖蛋白进行了凝集素印迹分析。除肠道外，在大多数组织的样本中都检测到了WFA阳性条带，尽管不同组织中条带与凝集素的数量和反应性有所不同。在用芽孢杆菌β-N-乙酰半乳糖胺酶或N-聚糖酶对印迹滤膜进行预处理后，未观察到凝集素结合。对除肠道外的牛组织膜糖蛋白经肼解释放的寡糖进行WFA-琼脂糖柱色谱分析，结果显示，释放的寡糖中有几%到18%能与100 mM N-乙酰半乳糖胺结合并从柱上洗脱下来。这些结果表明，来自多种牛组织的许多糖蛋白都含有具有GalNAcbeta1-->4GlcNAc结构的N-连接糖链，这表明这种糖基化在牛组织中更为广泛地存在。
