A MALDI-MS-based quantitative targeted glycomics (MALDI-QTaG) for total N-glycan analysis

Abstract

To develop a sensitive and quantitative method for monitoring the abnormal glycosylation of clinical and biopharmaceutical products. MALDI-MS-based quantitative targeted glycomics (MALDI-QTaG) was proposed for sensitive and quantitative analysis of total N-glycans. The derivatization reactions (i.e., amidation of sialic acid and incorporation of a positive charge moiety into the reducing end) dramatically increased the linearity (R-2 > 0.99) and sensitivity (limit of detection is 0.5 pmol/glycoprotein) relative to underivatized glycans. In addition, the analytical strategy was chromatographic purification-free and non-laborious process accessible to the high-throughput analyses. We used MALDI-QTaG to analyze the N-glycans of alpha-fetoprotein (AFP) purified from normal cord blood and HCC cell line (Huh7 cells). The total percentages of core-fucosylated AFP N-glycans from Huh7 cells and normal cord blood were 98 and 18 %, respectively. This MALDI-MS-based glycomics technology has wide applications in many clinical and bioengineering fields requiring sensitive, quantitative and fast N-glycosylation validation.