Electrophoretic studies of polygalacturonate oligomers and their interactions with metal ions

Polygalacturonic acid, a linear homopolysaccharide, was investigated by cap illary electrophoresis (CE) using linear polyacrylamide-coated capillaries and laser-induced fluorescence (LIF) detection. A successful separation of its fluorescently labeled oligomers was achieved through sieving in polyacr ylamide entangled matrices. The reaction conditions for the derivatization of polygalacturonic acid were optimized. In studying the interactions betwe en polygalacturonic acid and various metal ions, the end-label, free-soluti on electrophoretic (ELFSE) technique, developed earlier in our laboratory ( Sudor, J., Novotny, M. V., Anal. Chem. 1995, 67, 4205-4209) was found prefe rable to the sieving method. ELFSE is fast and convenient in that no polyme r solutions are needed for the separation. The investigation showed that fo r the moderately large oligomers, the strongest binding occurred with calci um and cadmium ions, while the smallest interaction was observed with magne sium ions.