Mass Spectrometric Study Of N-glycans In Natural Polymers

Protein,as an important natural polymer compound,plays an integral role in life activities.As one kind of the most extensive and important post-translational modifications of protein,N-linked glycosylation enriches the structure and function of proteins.N-glycans as the modified vector is also involved in life activities at various stages of the organism,the diversified biological functions of N-glycan showed great important biological significance and clinical value.As a kind of important biological community in wetland ecosystem,freshwater fish involved with water and other organisms in a wide range of mutual influences.It is of great significance to study the structure and function of biological macromolecules in freshwater fishes,which helps us to explore the characteristics of life activities of such organisms as well as the risk assessment of water environment.However,researches on biological macromolecules associated with freshwater fish develop slowly,especially in glycomics.In this research,N-glycans isolated from the serum of seven different kind of freshwater fishes were profiled based on MALDI-MS and the derivatization of permethylation.The differences in structure and abundance of N-Glycans isolated from these fish serums were discussed.Methylamidation,as a gentle derivatization method,was used to uncover the Oacetylation of sialoglycans isolated from freshwater fish for the first time.The distribution of O-acetylation on sialic acids was analyzed by LC-MS/MS.By these works,we established a novel method to uncover the O-acetylation of sialoglycans,repeatability experiments showed us a stable and feasible valuation.This work has enriched the biological information of freshwater fish glycomics.This combination of methylamidation and permethylation shows great potential in the study of the interrelation between sialoglycans modification and diseases,also in the research of uncovering the novel biomarkers of glycosylated proteins.