Saha S K, Brewer C F
Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461.
Carbohydr Res. 1994 Feb 17;254:157-67. doi: 10.1016/0008-6215(94)84249-3.
The concentrations of methyl glycosides, oligosaccharides, glycopeptides, and glycoproteins can be accurately determined by using calibration curves composed of the appropriate monosaccharide(s) obtained with a modified version of the colorimetric phenol-sulfuric acid method. Calibration curves of micrograms sugar vs. 490 nm for Man, Glc, or Gal are shown to provide reliable determinations (typically +/- 3-4%) of corresponding methyl glycosides and linear and branched-chain oligosaccharides containing the corresponding reactive hexose residue. For complex oligosaccharides containing a known mixture of reactive hexose units, the appropriate mixture of monosaccharides are shown to provide equally accurate calibration curves for concentration determinations. In the case of the soybean agglutinin, which is a tetramer possessing one Man9 oligomannose-type chain per subunit, the protein concentration was determined from the Man calibration curve which agreed with that obtained from the molar extinction coefficient of the protein.
甲基糖苷、寡糖、糖肽和糖蛋白的浓度可以通过使用校准曲线准确测定，该校准曲线由用比色酚硫酸法的改进版本获得的适当单糖组成。甘露糖、葡萄糖或半乳糖的微克糖与490nm的校准曲线显示，对于相应的甲基糖苷以及含有相应活性己糖残基的线性和支链寡糖，能提供可靠的测定结果（通常为±3-4%）。对于含有已知活性己糖单元混合物的复杂寡糖，适当的单糖混合物可提供同样准确的校准曲线用于浓度测定。就大豆凝集素而言，它是一种四聚体，每个亚基含有一条Man9寡甘露糖型链，蛋白质浓度由甘露糖校准曲线确定，该曲线与从蛋白质的摩尔消光系数获得的结果一致。
