Rapid and sensitive analysis of mucin-type glycans using an in-line flow glycan-releasing apparatus

Rapid and sensitive analysis of glycans is essential for glycomics. We previously reported an apparatus, the AutoGlycoCutter (AGC), for rapid release of O-linked glycans under alkaline conditions and its application to rapid analysis of glycans in proteoglycans. We now report an application of the AGC to obtain mucin-type glycans with reducing end (i.e., hemiacetal group) within only 3 min. The released oligosaccharides could be labeled with fluorescent 2-aminobenzoic acid for analysis by normal-phase high-performance liquid chromatography (NP-HPLC) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). We could detect O-glycans from as low as 5 pmol of bovine caseino glycomacropeptide (CGMP) by the proposed procedures. The validity of the current method was shown by the analyses of the released O-glycans from some standard glycoproteins: bovine submaxillary mucin, bovine fetuin, porcine stomach mucin, and human colostrum immunoglobulin A. The advantage of the current method was also demonstrated in comparative analysis of mucin-type glycans in CGMP derived from three different animal species.