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外文期刊>The biochemical journal
>Studies on the carbohydrate moiety of α1-acid glycoprotein (orosomucoid) by using alkaline hydrolysis and deamination by nitrous acid
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Studies on the carbohydrate moiety of α1-acid glycoprotein (orosomucoid) by using alkaline hydrolysis and deamination by nitrous acid
pAlkaline hydrolysis followed by deamination with nitrous acid was applied for the first time to a glycoprotein, human plasma αsub1/sub-acid glycoprotein (orosomucoid). This procedure, which specifically cleaves the glycosaminidic bonds, yielded well-defined oligosaccharides. The trisaccharides, which were obtained from the native protein, consisted of a sialic acid derivative, galactose and 2,5-anhydromannose. The linkage between galactose and 2,5-anhydromannose is most probably a (1→4)-glycosidic bond. A hitherto unknown linkage between iN/i-acetylneuraminic acid and galactose was also established, namely a (2→2)-linkage. The three linkages between sialic acid and galactose described in this paper appear to be about equally resistant to mild acid hydrolysis. The disaccharide that was derived from the desialized glycoprotein consisted of galactose and 2,5-anhydromannose. Evidence was obtained for the presence of a new terminal sialyl→iN/i-acetylglucosamine disaccharide accounting for approximately 1mol/mol of protein. The presence of this disaccharide may explain the relatively severe requirements for the complete acid hydrolysis of the sialyl residues. The present study indicates that alkaline hydrolysis followed by nitrous acid deamination in conjunction with gas–liquid chromatography will afford relatively rapid determination of the partial structure of the complex carbohydrate moiety of glycoproteins./p
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机译：>首次将碱性水解，然后用亚硝酸脱氨处理的糖蛋白是人血浆中的α 1 -酸糖蛋白（类骨粉）。该过程特别地切割糖苷键，产生了明确的寡糖。从天然蛋白质获得的三糖由唾液酸衍生物，半乳糖和2，5-脱水甘露糖组成。半乳糖和2，5-脱水甘露糖之间的键合很可能是（1→4）-糖苷键。还建立了迄今未知的 N -乙酰神经氨酸与半乳糖之间的键，即（2→2）键。本文所述的唾液酸和半乳糖之间的三个连接似乎对轻度酸水解具有大约相同的抗性。源自脱盐的糖蛋白的二糖由半乳糖和2,5-脱水甘露糖组成。获得了新的末端唾液酸→N i-乙酰基葡糖胺二糖的存在的证据，其占蛋白质的约1mol / mol。该二糖的存在可以解释对唾液酸残基的完全酸水解的相对严格的要求。本研究表明，碱水解然后亚硝酸脱氨基结合气液色谱法可以相对快速地测定糖蛋白复杂碳水化合物部分的部分结构。
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