Capillary gel electrophoresis separation of high‐mannose type oligosaccharides derivatized by 1‐aminopyrene‐3,6,8‐trisulfonic acid

In this paper we report the capillary gel electrophoresis separation of 1‐amino‐pyrene‐3,6,8‐trisulfonic acid (APTS) labeled oligosaccharides, released enzymatically from bovine pancreatic ribonuclease B. The released and labeled high‐mannose structures were identified by spiking the separated peaks with the appropriate commercially available individual oligosaccharides. Baseline separation of the three positional isomers of the mannose‐7 and mannose‐8 oligosaccharides was attained. Comparison of the electrophoretic mobilities of the high‐mannose type branched carbohydrates to the linear molecules of malto‐oligosaccharides (glucose oligomers) have been shown using different gel concentrations in the running buffer system. We observed that increasing gel concentration in the running buffer causes an increase in the relative mobility values of the high‐mannose type carbohydrate molecules compared to the linear glucose oligomers. Analysis of our data indicated that this increase in relative migration time was not due to sieving, but seemed to be related to the mannose content and hydrodynamic volume of the branched glycans as well as to the viscosity of the separation medium.