Changes in human IgG galactosylation and sialylation have been associated with several inflammatory diseases which are a major burden on the health care system. A large body of work on well... Show moreChanges in human IgG galactosylation and sialylation have been associated with several inflammatory diseases which are a major burden on the health care system. A large body of work on well-established glycomic and glycopeptidomic assays has repeatedly demonstrated inflammation-induced changes in IgG glycosylation. However, these assays are usually based on specialized analytical instrumentation which could be considered a technical barrier for uptake by some laboratories. Hence there is a growing demand for simple biochemical assays for analyzing these glycosylation changes. We have addressed this need by introducing a novel glycosidase plate-based assay for the absolute quantification of galactosylation and sialylation on IgG. IgG glycoproteins are treated with specific exoglycosidases to release the galactose and/or sialic acid residues. The released galactose monosaccharides are subsequently used in an enzymatic redox reaction that produces a fluorescence signal that is quantitative for the amount of galactosylation and, in-turn, sialylation on IgG. The glycosidase plate-based assay has the potential to be a simple, initial screening assay or an alternative assay to the usage of high-end analytical platforms such as HILIC-FLD-MSn when considering the analysis of galactosylation and sialylation on IgG. We have demonstrated this by comparing our assay to an industrial established HILIC-FLD-MSn glycomic analysis of 15 patient samples and obtained a Pearson's r correlation coefficient of 0.8208 between the two methods. Show less
This Thesis describes a strategy to synthesize 1,2-cis-oligosaccharides modulated by additives, such as dimethylformamide (DMF), triphenylphosphine oxide (Ph3P=O) and N-methyl(phenyl)formamide (MPF... Show moreThis Thesis describes a strategy to synthesize 1,2-cis-oligosaccharides modulated by additives, such as dimethylformamide (DMF), triphenylphosphine oxide (Ph3P=O) and N-methyl(phenyl)formamide (MPF), using building blocks that carry solely benzyl type protecting groups and are therefore of uniform reactivity. These three additives were used for different classes of donor-acceptor combinations. The additive DMF was mainly used to modulate glycosylations of per-benzylated glucosyl donors and secondary alcohol acceptors. The TMSI-Ph3P=O condition was used to glycosylate the more reactive primary alcohol acceptors. The MPF additive, which forms less stable anomeric imidinium ion intermediates than DMF, was used for donors that are somewhat less reactive, such as those in the 2-azido-2-deoxy series. Show less
Zhang, Z.J.; Westhrin, M.; Bondt, A.; Wuhrer, M.; Standal, T.; Holst, S. 2019
