High‐performance capillary electrophoresis of gangliosides

Abstract

Gangliosides are sialic acid-containing glycosphingolipids. In aqueous media, these glycolipids have been shown to exist as stable micelles. Ganglioside micelles could be analyzed by high-performance zonal capillary electrophoresis in uncoated fused-silica capillaries within 10 min. The mass sensitivity determined by monitoring the absorption of ultraviolet light at 195 nm was in the order of 10⁻¹¹ mol. Increasing the pH of the running buffer from 3.0 to 7.4 or the voltage from 10 to 30 kV increased the relative mobilities of gangliosides. By contrast, increasing the ionic strength of the buffer decreased the migration and broadened the elution peak widths of gangliosides. Ganglioside 1 The abbreviations used for gangliosides are according to the recommendations of the Nomenclature Committee, International Union of Pure and Applied Chemistry [46]. The basic designation of ganglio-series gangliosides are based on the Svennerholm system [47]. For example: G_Ml, II³NeuAc-GgOse₄Cer. micelles including G_M1, G_D1b and G_T1b were resolved into separate peaks by capillary electrophoresis at physiological pH shortly after mixing. Upon prolonged inc ubation, the ganglioside peaks merged to form a single species. The fusion process was temperature-dependent. At 50°C, formation of mixed micelles between polysialogangliosides G_D1b and G_T1b was complete within 30 min. In contrast, no fusion of the ganglioside peaks was observed at 0°C even after 75h. Formation of mixed micelles between G_D1b and other polysialogangliosides including G_D1a, G_T1b and G_Q1b at 37°C required 1.5, 3.0 and 2.0 h, respectively. Formation of mixed micelles between monosialoganglioside G_M1 and polysialogangliosides were 6- to 36-fold slower. No fusion was observed between monosialogangliosides G_M1 and G_M2 after 2 days of incubation. These findings indicate that polysialogangliosides may have higher propensities than monosialoganglioside to form mixed micelles.