‘Brain‐type’ N‐glycosylation of asialo‐transferrin from human cerebrospinal fluid

Abstract

Asiolo‐transferrin from human cerebrospinal fluid was purified to homogeneity. Investigation of the structural characteristics of its oligosaccharides support our hypothesis of ‘brain‐type’ glycosylation of intrathecally synthesized cerebrospinal fluid proteins. For carbohydrate structural analysis, high‐pH anion‐exchange chromatography, methylation analysis, liquid secondary ion‐ and matrix‐assisted laser desorption/ ionization mass spectrometry of the permethylated derivatives were used. The major structure turned out to be a complex‐type agalacto‐diantennary oligosaccharide with bisecting N‐acetylglucosamine and proximal fucose. Analysis of a second transferrin preparation containing both asialo‐ and sialo‐transferrin revealed another major glycan species derived from the sialylated transferrin variant which is galactosylated and lacks bisecting N‐acetylglucosamine and fucose.