Downs F, Peterson C, Murty V L, Pigman W
Int J Pept Protein Res. 1977 Oct;10(4):315-22. doi: 10.1111/j.1399-3011.1977.tb02803.x.
The carbohydrate side chains of mucus-type glycoproteins are O-glycosidic bonds between N-acetylgalactosamine to the hydroxyl groups of serine and threonine in the protein core. The alkaline catalyzed beta-elimination reaction, in the presence of sodium borohydride, is used for determining the number of side chains. The present paper presents a study of the quantitativeness of the alkaline borohydride procedure, using four parameters: the loss of seryl and threonyl residues, the formation of alanine and 2-aminobutanoic acid; the decrease in N-acetylhexosamine and the recovery of the amino sugar alcohols. Bovine, ovine and porcine submandibular glycoproteins were studied. Evidence is presented for the existence of N-acetylglucosamine involvement in O-glycosidic linkages to serine and threonine. Results for the relative rates of beta-elimination indicate that serine-linked glycosides are released more rapidly than threonine-linked glycosides.
黏液型糖蛋白的碳水化合物侧链是通过N-乙酰半乳糖胺与蛋白质核心中丝氨酸和苏氨酸的羟基形成O-糖苷键。在硼氢化钠存在下的碱性催化β-消除反应用于确定侧链的数量。本文使用四个参数对碱性硼氢化钠方法的定量性进行了研究：丝氨酸和苏氨酸残基的损失、丙氨酸和2-氨基丁酸的形成；N-乙酰己糖胺的减少以及氨基糖醇的回收率。对牛、羊和猪的下颌下糖蛋白进行了研究。有证据表明N-乙酰葡糖胺参与了与丝氨酸和苏氨酸的O-糖苷键连接。β-消除相对速率的结果表明，与丝氨酸相连的糖苷比与苏氨酸相连的糖苷释放得更快。
