Cahour A, Debeire P, Hartmann L, Montreuil J
Biochem J. 1983 Apr 1;211(1):55-63. doi: 10.1042/bj2110055.
The well-known heterogeneity of normal and pathological immunoglobulins M was investigated in a study involving the characterization of their carbohydrate moieties. Oligosaccharide units were released from the native molecule by hydrazinolysis, and they were fractionated by affinity chromatography on a concanavalin A-Sepharose column to yield separate N-acetyl-lactosaminic-type and oligomannosidic-type structures. Further identification of these oligosaccharides was attempted by t.l.c. on silica gel and by determination of their monosaccharide compositions. A comparative study of the oligosaccharide units belonging to each population of immunoglobulin M was possible. Similarities were found in the occurrence of both types of oligosaccharide structures, and, in addition, a common double heterogeneity could be demonstrated for N-acetyl-lactosaminic-type structures: they could be resolved by affinity chromatography into bi-, tri- and tetra-antennary structures, and they also showed differences in N-acetylneuraminic acid content. Though some variations were observed in the exact composition of the oligosaccharide units within each population, it was possible to consider a representative oligosaccharide-unit composition of normal immunoglobulin M as a standard for comparison. On this basis a predominance of multi-antennary structures was observed in the more glycosylated pathological immunoglobulins M (10% carbohydrate content), whereas oligomannosidic structures were increased in pathological immunoglobulins M with a lower content of carbohydrates (7%). These variations are thought to reflect differences in the biosynthetic processing pathway of the carbohydrate units of the pathological immunoglobulins M or the enhanced expression of a molecular clone.
在一项涉及对正常和病理性免疫球蛋白M的碳水化合物部分进行表征的研究中，对其众所周知的异质性进行了调查。通过肼解从天然分子中释放出寡糖单元，并通过在伴刀豆球蛋白A-琼脂糖柱上进行亲和色谱对其进行分级分离，以产生单独的N-乙酰乳糖胺型和寡甘露糖型结构。通过硅胶薄层层析和测定其单糖组成，尝试对这些寡糖进行进一步鉴定。对属于每个免疫球蛋白M群体的寡糖单元进行了比较研究。发现两种类型的寡糖结构在出现情况上存在相似性，此外，对于N-乙酰乳糖胺型结构，可以证明存在共同的双重异质性：它们可以通过亲和色谱分离为双天线、三天线和四天线结构，并且它们在N-乙酰神经氨酸含量上也存在差异。尽管在每个群体中寡糖单元的确切组成上观察到了一些变化，但可以将正常免疫球蛋白M的代表性寡糖单元组成作为比较标准。在此基础上，在糖基化程度更高的病理性免疫球蛋白M（碳水化合物含量为10%）中观察到多天线结构占优势，而在碳水化合物含量较低（7%）的病理性免疫球蛋白M中寡甘露糖型结构增加。这些变化被认为反映了病理性免疫球蛋白M碳水化合物单元生物合成加工途径的差异或分子克隆的增强表达。
