title: MALDI-MS analysis of sialylated N-glycan linkage isomers using solid-phase two step derivatization method.
abstract: Sialic acids usually locate at the terminal of many glycan structures in either α(2,3) or α(2,6) linkage, playing different roles in various biological and pathological processes. Several linkage specific carboxyl derivatization methods have been reported to discriminate between α(2,3) and α(2,6)-linked sialic acids by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Among them, ethyl esterification was recently reported to achieve linkage specific derivatization between α(2,3) and α(2,6)-linked sialic acids with good selectivity. However, the method suffered from the instability of the generated lactones and byproducts of the derivatives. To overcome these shortcomings, a solid-phase two step derivatization method was introduced to convert the α(2,6)-linked sialic acid into ethyl esters and the α(2,3)-inked counterparts into N-methyl amides, respectively. Under the optimized derivatization conditions, our method was able to achieve accurate relative quantification of N-glycan as well as their corresponding sialylated linkage types, superior to the ethyl esterification method. The solid phase derivatization strategy was further applied to investigate N-glycans from biosimilar antibody drug and human serum from patients and healthy volunteers. This method has the potential to be used in the biomarker discovery and pharmaceutical industry.
authors.affiliation: Britton Chance Center for Biomedical Photonics at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Henghui
authors.initials: H
authors.lastname: Li
authors.affiliation: Britton Chance Center for Biomedical Photonics at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Wenjie
authors.initials: W
authors.lastname: Gao
authors.affiliation: Britton Chance Center for Biomedical Photonics at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Feng
authors.affiliation: Britton Chance Center for Biomedical Photonics at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
authors.forename: Bi-Feng
authors.initials: BF
authors.lastname: Liu
authors.affiliation: Britton Chance Center for Biomedical Photonics at Wuhan National Laboratory for Optoelectronics-Hubei Bioinformatics & Molecular Imaging Key Laboratory, Systems Biology Theme, Department of Biomedical Engineering, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China. Electronic address: xliu@mail.hust.edu.cn.
authors.forename: Xin
authors.initials: X
authors.lastname: Liu
mesh_terms: D011134:Polysaccharides / Q000737:chemistry*; D012794:Sialic Acids / Q000032:analysis*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D011134:Polysaccharides; D012794:Sialic Acids
keywords: Ethyl esterification; Glycan; Linkage-specific sialic acid; Matrix-assisted laser desorption/ionization mass spectrometry; Methylamidation; Solid phase