Specific and Reversible Enrichment of Early-Stage Glycated Proteome Based on Thiazolidine Chemistry and Palladium-Mediated Cleavage

Comprehensive analysis of protein
glycation is important for better
understanding of its formation mechanism and biological significance.
The current preconcentration methods of glycated proteome mainly depend
on the reversible combination of boronic acid and cis-dihydroxy group by pH adjustment, but it has inherent limitations
(e.g., poor specificity and time-consuming). Herein, for the first
time, a novel enrichment method for glycated peptides is proposed
based on the reversible chemical reaction between aldehyde and 1,2-aminothiol
groups, in which oxidized glycated peptides are captured onto the
magnetic nanoparticles via thiazolidine chemistry and then released
by palladium-mediated cleavage. The method is rapid, with excellent
selectivity (even at a 1:1000 molar ratio of glycated peptides/nonglycated
peptides) and high sensitivity (1 fmol/μL). As a good evidence,
1549 glycated peptides were identified from glycated human serum with
94.6% specificity, providing a powerful technique for high-throughput
analysis of glycated peptides.