Chemical Labeling of Sialyloligo/polymer

Abstract

In most cases, sialic acids are present as α2,3- or α2,6-linked monosialyl residues at the non-reducing terminal positions of glycan chains on glycoproteins and glycolipids. In rare cases, sialic acids are linked to each other to form a polymerized structure, di/oligo/polysialic acid (diSia/oligoSia/polySia). The polySia glycotope exhibits structural diversity in the sialic acid components (Neu5Ac, Neu5Gc, and KDN), in the intersialyl linkages (α2 → 5 _Oglycolyl , α2 → 8, α2 → 9, and α2 → 8/9) and in the degree of polymerization (DP). Highly sensitive chemical methods to detect di/oligo/polysialic acids were developed (Sato et al. 1998, 1999) with a highly specific reagent for α-keto acid (Hara et al. 1987), and frequent di/oligo/polysialylation on glycoproteins were demonstrated (Sato 2004).