Lisowska E, Duk M, Dahr W
Carbohydr Res. 1980 Feb;79(1):103-13. doi: 10.1016/s0008-6215(00)85135-6.
Alkali-borohydride degradation of M or N blood-group active, tryptic glycopeptides and glycoproteins was performed under conditions giving the reduced oligosaccharides in a yield significantly improved over that reported earlier. Degradation of desialosylated glycoproteins yielded beta-D-Galp-(1 leads to 3)-D-GalNAcol, D-GalNA-col, and Galol in a ratio of approximately 30:1:1. GalNAc was shown to be alpha-D-linked to the polypeptide chain. Degradation of the glycopeptides gave the tetrasaccharide, NeuAc-(2 leads to 3)-beta-D-Galp-(leads to 3)-[NeuAc-(2 leads to 6)]-D-GalNAcol, and two trisaccharides, NeuAc-(2 leads to 3)-beta-D-Galp-(1 leads to 3)-D-GalNAcol and beta-D-Galp-(1 leads to 3)-[NeuAc-(2 leads to 6)]-D-GalNAcol, in a molar ratio of approximately 8:3:1. These oligosaccharides were accompanied by minor amounts of unidentified compounds showing identical electrophoretic mobility when derived from M and N glycopeptides. During isolation of the reduced oligosaccharides, the release of sialic acid did not exceed 5.5%, indicating that only a part of the trisaccharide portion might have arisen as a result of desialosylation of the tetrasaccharide. No differences between the degradation products derived from M and N glycoproteins were found, and the presence of significant amounts of larger, alkali-labile oligosaccharides was not observed.
在能使还原寡糖产率显著高于先前报道的条件下，对M或N血型活性胰蛋白酶糖肽和糖蛋白进行了碱硼氢化物降解。去唾液酸化糖蛋白的降解产生了β-D-半乳糖基-(1→3)-D-氨基半乳糖醇、D-氨基半乳糖醇和半乳糖醇，其比例约为30:1:1。已证明N-乙酰半乳糖胺以α-D-连接方式与多肽链相连。糖肽的降解产生了四糖NeuAc-(2→3)-β-D-半乳糖基-(1→3)-[NeuAc-(2→6)]-D-氨基半乳糖醇，以及两种三糖，NeuAc-(2→3)-β-D-半乳糖基-(1→3)-D-氨基半乳糖醇和β-D-半乳糖基-(1→3)-[NeuAc-(2→6)]-D-氨基半乳糖醇，摩尔比约为8:3:1。这些寡糖伴随着少量未鉴定的化合物，当从M和N糖肽衍生而来时，它们显示出相同的电泳迁移率。在还原寡糖的分离过程中，唾液酸的释放不超过5.5%，这表明只有一部分三糖部分可能是四糖去唾液酸化的结果。未发现源自M和N糖蛋白的降解产物之间存在差异，也未观察到大量较大的、对碱不稳定的寡糖的存在。
