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Daejeon, South Korea

Oh M.J.,Chungnam National University | Hua S.,Asia Glycomics Reference Site | Kim U.,Chungnam National University | Kim H.J.,Chungnam National University | And 3 more authors.
Bioanalysis | Year: 2016

Glycosylation plays an important role in ensuring the proper structure and function of most biotherapeutic proteins. Even small changes in glycan composition, structure, or location can have a drastic impact on drug safety and efficacy. Recently, glycosylation has become the subject of increased focus as biopharmaceutical companies rush to create not only biosimilars, but also biobetters based on existing biotherapeutic proteins. Against this backdrop of ongoing biopharmaceutical innovation, updated methods for accurate and detailed analysis of protein glycosylation are critical for biopharmaceutical companies and government regulatory agencies alike. This review summarizes current methods of characterizing biopharmaceutical glycosylation, including compositional mass profiling, isomer-specific profiling and structural elucidation by MS and hyphenated techniques. © 2016 Future Science Ltd. Source


Park J.-S.,University of Ulsan | Ji I.J.,Asia Glycomics Reference Site | Ji I.J.,Chungnam National University | An H.J.,Asia Glycomics Reference Site | And 5 more authors.
Traffic | Year: 2015

The triggering receptor expressed on myeloid cells 2 (TREM2) is an immune-modulatory receptor involved in phagocytosis and inflammation. Mutations of Q33X, Y38C and T66M cause Nasu-Hakola disease (NHD) which is characterized by early onset of dementia and bone cysts. A recent, genome-wide association study also revealed that single nucleotide polymorphism of TREM2, such as R47H, increased the risk of Alzheimer's disease (AD) similar to ApoE4. However, how these mutations affect the trafficking of TREM2, which may affect the normal functions of TREM2, was not known. In this study, we show that TREM2 with NHD mutations are impaired in the glycosylation with complex oligosaccharides in the Golgi apparatus, in the trafficking to plasma membrane and further processing by γ-secretase. Although R47H mutation in AD affected the glycosylation and normal trafficking of TREM2 less, the detailed pattern of glycosylated TREM2 differs from that of the wild type, thus suggesting that precise regulation of TREM2 glycosylation is impaired when arginine at 47 is mutated to histidine. Our results suggest that the impaired glycosylation and trafficking of TREM2 from endoplasmic reticulum/Golgi to plasma membrane by mutations may inhibit its normal functions in the plasma membrane, which may contribute to the disease. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd. Source


Hua S.,Asia Glycomics Reference Site | Hua S.,Chungnam National University | Hu C.Y.,University of California at Davis | Kim B.J.,Chungnam National University | And 10 more authors.
Journal of Proteome Research | Year: 2013

Despite recent advances, site-specific profiling of protein glycosylation remains a significant analytical challenge for conventional proteomic methodology. To alleviate the issue, we propose glyco-analytical multispecific proteolysis (Glyco-AMP) as a strategy for glycoproteomic characterization. Glyco-AMP consists of rapid, in-solution digestion of an analyte glycoprotein (or glycoprotein mixture) by a multispecific protease (or protease cocktail). Resulting glycopeptides are chromatographically separated by isomer-specific porous graphitized carbon nano-LC, quantified by high-resolution MS, and structurally elucidated by MS/MS. To demonstrate the consistency and customizability of Glyco-AMP methodology, the glyco-analytical performances of multispecific proteases subtilisin, pronase, and proteinase K were characterized in terms of quantitative accuracy, sensitivity, and digestion kinetics. Glyco-AMP was shown be effective on glycoprotein mixtures as well as glycoproteins with multiple glycosylation sites, providing detailed, quantitative, site- and structure-specific information about protein glycosylation. © 2013 American Chemical Society. Source


Hua S.,Asia Glycomics Reference Site | Hua S.,Chungnam National University | Oh M.J.,Asia Glycomics Reference Site | Oh M.J.,Chungnam National University | And 7 more authors.
TrAC - Trends in Analytical Chemistry | Year: 2015

Glycosylation is one of the most critical factors affecting the quality, the safety and the potency of recombinant erythropoietin. Small changes during production can significantly affect glycosylation, and so the potency, of recombinant erythropoietin. Due to patent expirations, we expect biosimilar erythropoietins to play an increasing role in healthcare in coming years. Governmental regulatory agencies and biopharmaceutical companies therefore have an urgent need for reliable methods that can accurately characterize and evaluate these biological products, particularly in terms of their glycosylation. In this review, we provide an overview of current analytical tools for qualitative and quantitative analysis of erythropoietin glycosylation. © 2015. Source


Ji I.J.,Asia Glycomics Reference Site | Ji I.J.,Chungnam National University | Hua S.,Asia Glycomics Reference Site | Hua S.,Chungnam National University | And 12 more authors.
Analytical Chemistry | Year: 2015

Tissue glyco-capture (TGC), a highly sensitive MS-compatible method for extraction of glycans from tissue, was combined with structure-specific nano-LC/MS for sensitive and detailed profiling of the mouse brain glycome. Hundreds of glycan structures were directly detected by accurate mass MS and structurally elucidated by MS/MS, revealing the presence of novel glycan motifs such as antennary fucosylation, sulfation, and glucuronidation that are potentially associated with cellular signaling and adhesion. Microgram-level sensitivity enabled glycomic analysis of specific regions of the brain, as demonstrated on not only brain sections (with a one-dimensional spatial resolution of 20 μ) but also isolated brain structures (e.g., the hippocampus). Reproducibility was extraordinarily high (R > 0.98) for both method and instrumental replicates. The pairing of TGC with structure-specific nano-LC/MS was found to be an exceptionally powerful platform for qualitative and quantitative exploration of the brain glycome. © 2015 American Chemical Society. Source

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