Raju T S, Davidson E A
Department of Biochemistry and Molecular Biology, Georgetown University Medical School, Washington, D.C. 20007.
Biochem Mol Biol Int. 1994 Nov;34(5):943-54.
A modified procedure for chemical deglycosylation of glycoproteins containing sialylated and/or O-linked oligosaccharides, using anhydrous trifluoromethane sulfonic acid (TFMSA) is described. Although sialic acid residues are acid labile, it has been known that anhydrous TFMSA does not effectively remove carbohydrate side chains from glycoproteins if they are sialylated. In this procedure, sialic acid residues were removed by mild acid hydrolysis and the desialylated glycoprotein was treated with anhydrous TFMSA reagent under conditions which remove all the carbohydrate residues except the core D-GalNAc linked to serine/threonine. The core D-GalNAc residues were removed by reacting the glycoprotein with periodate followed by a second treatment with anhydrous TFMSA; this procedure gave a completely deglycosylated protein. The protein thus obtained was soluble in aqueous buffers and useful for biochemical and biophysical studies. The method was successfully employed to isolate polypeptides from alpha 1-acid glycoprotein (N-linked), fetuin, canine tracheal mucin and gastric mucin.
本文描述了一种使用无水三氟甲磺酸（TFMSA）对含有唾液酸化和/或O-连接寡糖的糖蛋白进行化学去糖基化的改进方法。虽然唾液酸残基对酸不稳定，但已知如果糖蛋白是唾液酸化的，无水TFMSA不能有效地从糖蛋白中去除碳水化合物侧链。在该方法中，通过温和的酸水解去除唾液酸残基，然后在去除与丝氨酸/苏氨酸连接的核心D-GalNAc以外的所有碳水化合物残基的条件下，用无水TFMSA试剂处理去唾液酸化的糖蛋白。通过使糖蛋白与高碘酸盐反应，然后再用无水TFMSA处理，去除核心D-GalNAc残基；该方法得到完全去糖基化的蛋白质。由此获得的蛋白质可溶于水性缓冲液，可用于生化和生物物理研究。该方法已成功用于从α1-酸性糖蛋白（N-连接）、胎球蛋白、犬气管粘蛋白和胃粘蛋白中分离多肽。
