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...[ Read more ]

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.