Moschera J, Pigman W
Carbohydr Res. 1975 Mar;40(1):53-67. doi: 10.1016/s0008-6215(00)82668-3.
A purified glycoprotein, designated RSL-major, was isolated from the rat sublingual gland by means of the procedure of Tettamanti and Pigman. It was found to be homogeneous by analytical ultracentrifugation, to have a mol. wt. of 2-2 times 10-6, and to contain 81 percent (W/W) of carbohydrate, which consists mainly of sialic acid, 2-acetamido-2-deocy-D-glucose, 2-acetamido-2-deocy-D-galactose, and D-galactose in the molar ratio of 1.4:1.4:1.0:1.5; small amounts of fucose and mannose [1.2 and 2.8 percent (W/W), respectively] were also present. The sialic acid residues were resistant to the action of V. cholerae neuraminidase. This resistance was completely abolished by removal of the O-acetyl groups contained in the sialic acid. The sialic acid in RSL-major appeared to be a mixture of N-acetyl-4-O-acetyl- and N-acetyl-4, 7(8)-di-O-acetylneuraminic acids. The carbohydrate to protein attachment of RSL-major was shown, by alkaline beta-elimination reaction, to consist of an O-glycosyl linkage between 2-acetamido-2-deoxy-D-galactosyl residues in the oligosaccharide chains and seryl and threonyl residues in the protein core. The average oligosaccharide, contained in RSL-major, was postulated to be a heptasaccharide. A second material, designated RSL-minor, and also isolated from the ratsublingual gland, was obtained as a mixture of glycoprotein(s) and hydroxylapatite gel, and was not purified further.
通过泰塔曼蒂和皮格曼的方法，从大鼠舌下腺中分离出一种纯化的糖蛋白，命名为RSL-主要成分。经分析超速离心发现其具有均一性，分子量为2.2×10⁶，含81%（重量/重量）的碳水化合物，主要由唾液酸、2-乙酰氨基-2-脱氧-D-葡萄糖、2-乙酰氨基-2-脱氧-D-半乳糖和D-半乳糖组成，摩尔比为1.4:1.4:1.0:1.5；还含有少量岩藻糖和甘露糖[分别为1.2%和2.8%（重量/重量）]。唾液酸残基对霍乱弧菌神经氨酸酶的作用具有抗性。通过去除唾液酸中含有的O-乙酰基，这种抗性完全消失。RSL-主要成分中的唾液酸似乎是N-乙酰-4-O-乙酰神经氨酸和N-乙酰-4,7(8)-二-O-乙酰神经氨酸的混合物。通过碱性β-消除反应表明，RSL-主要成分中碳水化合物与蛋白质的连接由寡糖链中的2-乙酰氨基-2-脱氧-D-半乳糖基残基与蛋白质核心中的丝氨酰和苏氨酰残基之间的O-糖基键组成。推测RSL-主要成分中平均寡糖为七糖。从大鼠舌下腺中还分离出第二种物质，命名为RSL-次要成分，它是糖蛋白和羟基磷灰石凝胶的混合物，未进一步纯化。
