Enrichment and analysis of glycated proteins

Glycation is a spontaneous post-translational modification of lysine, arginine, and the N-terminus of proteins. Protein glycation is closely related to the pathogenesis of human diseases, including diabetes, Alzheimer's disease, renal disease, and cancer. The levels of advanced glycation end products (AGEs) are positively correlated with the progression of many diseases. However, it remains challenging to analyze glycation-related products, such as reactive carbonyl species, Schiff bases, Amadori compounds, and AGEs, because of their high heterogeneity. Many analysis methods, such as fluorescence detection, immunoassays, and liquid chromatography-tandem mass spectrometry, have attempted to correlate glycation products with diseases. Some enrichment methods have been used to increase the probability of detection of glycated proteins due to their low abundance in blood plasma. This review summarizes the enrichment and analysis methods that are currently used to identify glycation as a disease biomarker in exploratory studies.