STRUCTURE OF ASIALO-CARBOHYDRATE UNITS OF HUMAN SEROTRANSFERRIN AS PROVEN BY 360 MHZ PROTON MAGNETIC-RESONANCE SPECTROSCOPY
STRUCTURE OF ASIALO-CARBOHYDRATE UNITS OF HUMAN SEROTRANSFERRIN AS PROVEN BY 360 MHZ PROTON MAGNETIC-RESONANCE SPECTROSCOPY
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DOI：
10.1016/0014-5793(77)80183-x
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发表时间：
1977-01-01
期刊：
影响因子：
3.5
通讯作者：
MONTREUIL, J
中科院分区：
文献类型：
--
作者：
DORLAND, L;HAVERKAMP, J;MONTREUIL, J
人血清转铁蛋白含有两条相同的糖链[1 -3]，关于其一级结构存在争议。Jamieson等人[3]假设支链结构，其中糖苷连接到N-乙酰葡糖胺/3L+ Asn上的支链甘露糖带有两条链：一条由甘露三糖组成，另一条由N-乙酰葡糖胺残基组成，并且两条链均由N-乙酰神经氨酸/N-乙酰乳糖胺单元终止。Spik等人[1，2]提出了一种更对称的结构，由被两个N-乙酰神经氨酰-N-乙酰乳糖胺单元取代的甘露三糖苷-二-N-乙酰壳二糖核心构成。图1所示的结构与前述结构有本质区别，因为它只有3个甘露糖残基而不是4个。本文描述了通过高分辨率1H核磁共振光谱对从血清转铁蛋白中分离的脱唾液酸糖肽（脱唾液酸聚糖-Asn）的结构进行的研究。特别地，分析了异头质子、甘露糖-H-2质子和N-乙酰基甲基的信号。对于这些信号的归属，相应的脱唾液酸-半乳糖-聚糖-Asn-Lys、糖-氨基酸GlcNAcpl+ Asn [4]和Mancz（1+ 6）Man/3（1+ 4）GlcNAc/3（1 + 4）[Fu& 1 + 6）] GlcNA@1 + Asn [5]和三糖Mancu（1 + 3）Mar@（1 + 4）GlcNAc [6]的光谱，代表脱唾液酸-聚糖-Asn的部分结构的化合物已用作参比化合物。这些物质中的单糖单元的编号与血清转铁蛋白糖肽中的编号相对应（见图1和表1）。
Human serotransferrin contains two identical carbohydrate chains [l-3] about the primary Structure of which controversy exsists. Jamieson et al.[3] suppose a branched structure, wherein the branching mannose, glycosidically linked to N-acetylglucosamine/3l+ Asn, bears two chains: one consisting of a mannotriose, the other of an N-acetylglucosamine residue and both terminated by an N-acetylneuraminyliV-acetyllactosamine unit. Spik et al.[1, 2] propose a more symmetrical structure, built up from a mannotriosido-di-N-acetylchitobiose core substituted by two N-acetylneuraminyl-N-acetyllactosamine units. This structure, presented in fig. 1 differs essentially from the foregoing structure since it has only 3 mannose residues instead of 4.In-this paper the investigation by high-resolution ‘H nuclear magnetic resonance spectroscopy of the structure of the asialoglycopeptide (asialo-glycan-Asn) isolated from serotransferrin is described. In particular the signals of the anomeric protons, the mannose-H-2 protons and the N-acetyl methyl groups were analysed. For the assignment of these signals, spectra of the corresponding asialo-agalacto-glycan-Asn-Lys, the glyco-amino acids GlcNAcpl+ Asn [4] and Mancz (1+ 6) Man/3 (1+ 4) G1cNAc/3 (1+ 4)[Fu&l+ 6)] GlcNA@ l+ Asn [5] and the trisaccharide Mancu (l+ 3) Mar@(l+ 4) GlcNAc [6], representing partial structures of the asialo-glycan-Asn have been used as reference compounds. The monosaccharide units in these substances are numbered in correspondence to the numbering in the serotransferrin glycopeptides (see fig. 1 and table 1).