High-performance capillary electrophoretic characterization of different types of oligo- and polysialic acid chains

We have carried out comparative structural analysis of novel oligo- and polysialic acid chains from diverse sources. Controlled acid hydrolysates of (a) colominic acid, alpha 2-->8-linked homopolymer of N-acetylneuraminic acid (Neu5Ac), (b) alpha 2-->8-linked oligo/polyNeu5Gc chains present in rainbow trout egg polysialoglycoprotein, and (c) alpha 2-->8-linked oligomers of deaminoneuraminic acid (KDN) residues of KDN-rich glycoprotein derived from rainbow trout vitelline envelope were analyzed by highperformance capillary electrophoresis (HPCE). The results showed that three different types of alpha 2-->8-linked oligosialic acids having same degree of polymerization can be separated by HPCE. A partial hydrolysate of colominic acid with mild acid was shown by CE to form intramolecular esters during the controlled hydrolysis and the subsequent workup procedure. In contrast, lactonization of (-->5-O-glycolyl-Neu5Gc alpha 2-->)n, alpha 2-->5-O-glycolyl-linked homopolymer of N-glycolylneuraminic acid (Neu5Gc) present in the egg jelly coat of sea urchin, did not take place as readily as in (-->8Neu5Ac alpha 2-->)n. (C) 1998 Academic Press.