Labeling of Oligosaccharides

Abstract

It is very difficult to detect a faint amount of oligosaccharide, because generally they have only hydroxyl and aldehyde groups. Thus, many studies have been reported on high-sensitive detection of oligosaccharides by radio-labeling or tagging of a UV-absorbent. In recent years, the method of introducing a fluorescent residue of small molecular weight into the reducing end came to be used worldwide as simplicity and a high-sensitivity detection method of the oligosaccharides. With a small and moderate hydrophobic fluorescent residue, the separability of the labeled oligosaccharides on reversed-phase HPLC remarkably improved. As a result, it is possible that combining several kinds of HPLCs separated up to 500 kinds of oligosaccharides. Such technique is called “Fluorescence labeling of the oligosaccharide”. Especially, the method with 2-aminopyridine (Hase et al. 1978) and 2-aminobenzamide (Bigge et al. 1995) as a fluorescent reagent is generally well known. The method of introducing 2-aminopyridine was reported primarily and still used worldwide (Fig. 1).