Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
Analyst. 2023 May 2;148(9):2035-2044. doi: 10.1039/d2an01762h.
Sugars play important roles in numerous biological processes, from providing energy to modifying proteins to alter their function. Glycosylation, the attachment of a sugar residue to a protein, is the most common post translational modification. Identifying the glycans on a protein is a useful tool both for pharmaceutical development as well as probing the proteome and glycome further. Sugars, however, are difficult analytes to probe due to their isomeric nature. In this work, Raman spectroscopy and surface enhanced Raman spectroscopy (SERS) are used to identify different monosaccharide species based on the vibrational modes of these isomeric analytes. The weak scattering of the sugars was overcome through conjugation with phenylboronic acid to provide a larger Raman scattering cross section and induce slight changes in the observed spectra associated with the structure of the monosaccharides. Spontaneous Raman, SERS in flow, and static SERS detection were performed in order to discriminate between arabinose, fructose, galactose, glucose, mannose, and ribose, as well as provide a method for identification and quantification for these sugar conjugates.
糖在许多生物过程中发挥着重要作用，从提供能量到修饰蛋白质以改变其功能。糖基化是将糖残基连接到蛋白质上，是最常见的翻译后修饰。鉴定蛋白质上的聚糖不仅是药物开发的有用工具，也是进一步探测蛋白质组和聚糖组的有用工具。然而，由于糖的异构性质，它们是难以探测的分析物。在这项工作中，拉曼光谱和表面增强拉曼光谱（SERS）用于根据这些异构体分析物的振动模式来识别不同的单糖种类。通过与苯硼酸缀合克服了糖的弱散射，提供了更大的拉曼散射截面，并引起了与单糖结构相关的观察光谱的轻微变化。为了在阿拉伯糖、果糖、半乳糖、葡萄糖、甘露糖和核糖之间进行区分，并为这些糖缀合物提供鉴定和定量的方法，进行了自发拉曼、流动 SERS 和静态 SERS 检测。
