Glycoproteomics of plasma based on narrow selectivity lectin affinity chromatography.

Lectin affinity chromatography using concanavalin A (Con A), Helix pomatia agglutinin (HPA), Lycopersicon esculentum lectin (LEL), Aleuria aurantia lectin (AAL) and Lens culinaris agglutinin (LCA) was used to investigate the utility of narrow selectivity lectins in the characterization of plasma glycoproteome diversity and to recognize cancer associated aberrations in glycosylation. Following affinity chromatographic selection, proteins were tryptically digested, the peptide fragments separated by reversed phase chromatography (RPC), and fractions from RPC identified by tandem mass spectrometry. The diversity of glycosylation found with narrow selectivity lectins was generally 2/3 that of Con A and not related to protein abundance. Small groups of proteins were found with each of the affinity columns, HPA, LEL, AAL, and LCA, that changed 3-fold or more in concentration between normal and breast cancer patient plasma. Although the number of cancer patients examined was too small to validate cancer marker candidates, they are clearly worth examining in a larger, more diverse patient population.