Koshy K M, Boggs J M
Department of Biochemistry, Hospital for Sick Children, Toronto, Ontario, Canada.
Anal Biochem. 1993 Feb 1;208(2):375-81. doi: 10.1006/abio.1993.1064.
After cation-exchange chromatographic separation of the charge isomers of human myelin basic protein, the citrulline-containing component was purified from the unbound fraction by gel permeation chromatography. Sephadex G75 (superfine) resolved high- and low-molecular-weight contaminants from the 18.5K myelin basic protein. However, carbohydrates leached from the column material by the acidic eluant interfered with citrulline quantitation by amino acid analysis. It appears highly probable that during acid hydrolysis of the protein, glucose reacts with citrulline, the ureido group of the latter forming a condensation product with the sugar which subsequently undergoes further chemical degradation to products which are not easily identifiable. Methods for removing the interfering sugars prior to amino acid analysis are discussed.
在对人髓鞘碱性蛋白的电荷异构体进行阳离子交换色谱分离后，通过凝胶渗透色谱从未结合部分中纯化出含瓜氨酸的组分。葡聚糖G75（超细）将18.5K髓鞘碱性蛋白中的高分子量和低分子量污染物分离。然而，酸性洗脱液从柱材料中浸出的碳水化合物干扰了通过氨基酸分析对瓜氨酸的定量。很有可能在蛋白质的酸水解过程中，葡萄糖与瓜氨酸反应，瓜氨酸的脲基与糖形成缩合产物，随后该缩合产物进一步化学降解为不易识别的产物。讨论了在氨基酸分析之前去除干扰糖的方法。
