Advanced LC-MS Methods for N-Glycan Characterization

N-glycosylation is one the main post-translational modification involving proteins that belong to all the three domains of life and plays a pivotal role in a number of biological functions including intercellular signaling and recognition. Glycosylation analysis in humans is an added value and a fundamental tool to characterize those genetic defects concerning glycan biosynthesis, such as Congenital Disorders of Glycosylation (CDG). Also, glycan alterations are associated to pathophysiology of major diseases as cancer and neurodegenerative dysfunctions. Concurrently, there is a growing interest of biopharmaceutical industries for the development of high-throughput methods for glycan analysis of therapeutic glycoproteins. N-linked glycans are commonly analyzed by liquid chromatography (LC) interfaced with fluorescence detection, but in recent years a growing number of research laboratories extended the application by coupling LC with mass spectrometry (MS) techniques. Furthermore, LC-MS has become the primary device for smart high-throughput analyses. Here we report an outline of the prevailing LC-MS techniques set up for N-glycan analysis, paying special attention to N-glycomic characterization of human serum, as the most available and informative biological source for diagnosis and disease investigations.