Microwave-assisted deglycosylation for rapid and sensitive analysis of N-glycans via glycosylamine derivatization.

A rapid and sensitive N-glycan profiling strategy for MALDI-MS incorporating the use of deglycosylation with microwave assistance and the co-derivatization of glycosylamine labeling with tris(2,4,6-trimethoxyphenyl)phosphonium acetic acid N-hydroxysuccinimide ester (TMPP-Ac-OSu) and methylamidation has been developed in this work. Notably, highly efficient release and tagging of N-glycans from ribonuclease B was achieved in less than 90 min, providing up to 35-fold enhancement of MALDI-MS sensitivity with comparison to underivatized N-glycans. After further validation with other two standard glycoproteins (ovalbumin and bovine fetuin), the proposed strategy was applied to human serum for preliminary pathological analysis of N-glycans between healthy and lung cancer individuals. As a result, significant differences (T test p value <0.01) of 6 glycan structures were determined from 54 detected N-glycan structures with only 50 nL of loading amount and further confirmed through PCA and ROC (AUC) analyses between two sample sets. Subsequently, the trend of each lung cancer stage and controls in expression of the selected glycans was implemented with T test and box-plots. Accordingly, these structures can be used as potential lung cancer glycan-based biomarkers and for further definition of cancer progression highlighting the ability of proposed method to rapidly and efficiently analyze N-glycome present in human serum. Graphical abstract MALDI-TOF MS analysis of N-glycans by microwave-assisted deglycosylation and glycosylamine derivatization.