THESIS
2019
xvi, 77 pages : illustrations (some color) ; 30 cm
Abstract
Advanced glycation end-products (AGEs) are a large group of compounds originated from
the Maillard reaction. Their formation and accumulation in human body are closely related to
aging and various degenerative diseases. AGEs can be formed by oxidative glycosylation and
reaction between lysyl or arginyl residues and dicarbonyl compounds such as glyoxal (GO) and
methylglyoxal (MGO). These reactive species are produced endogenously in normal cell
process and under conditions of oxidative stress, for example, monosaccharide autoxidation
and lipid peroxidation. Although the correlation between oxidative stress and AGEs formation
are frequently described, the effects of different extent of oxidative stress on AGEs formation
remain unclear.
In this study, the tendency of AGEs generati...[
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Advanced glycation end-products (AGEs) are a large group of compounds originated from
the Maillard reaction. Their formation and accumulation in human body are closely related to
aging and various degenerative diseases. AGEs can be formed by oxidative glycosylation and
reaction between lysyl or arginyl residues and dicarbonyl compounds such as glyoxal (GO) and
methylglyoxal (MGO). These reactive species are produced endogenously in normal cell
process and under conditions of oxidative stress, for example, monosaccharide autoxidation
and lipid peroxidation. Although the correlation between oxidative stress and AGEs formation
are frequently described, the effects of different extent of oxidative stress on AGEs formation
remain unclear.
In this study, the tendency of AGEs generation is studied by exposing different dicarbonyls,
GO and MGO, and oxidative stressor, Fe-EDTA, to protein and Escherichia coli. N
ε-carboxymethyllysine (CML), a well-studied and frequently used biomarker for measuring AGEs content in food and biological systems, was quantitated simultaneously with N
ε-carboxyethyllysine (CEL) to account for the oxidative stress-induced damages to E. coli.
Hydrophilic interaction chromatography (HILIC) was employed for separating AGEs prior to
tandem mass spectrometry (MS/MS) detection in the analysis of CML and CEL. Isotopically
labelled internal standards were applied for accounting any analyte loss during sample
preparation and correcting errors arisen from instrumental analysis. The data revealed that the
CML formation caused by Fe-EDTA was contributed equally by oxidative fragmentation of
Amadori products, and the generated GO. Interestingly, the formation of CEL may lead to an
alternative pathway for the generation of CEL by glycosylation of Amadori product, which has
not been considered before.
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