A group from Department of Experimental and Translational Ophthalmology, University Medical Center, Johannes Gutenberg University, Mainz, Germany has reported about characterization of N-glycoproteins from human tear films.
The main objective of this study was to develop a lectin-based affinity purification method for the enrichment of glycoproteins/glycopeptides from human tear film and the MS-based detection as well as localization of their specific N-glycosylation sites.
The best-performing multi-lectin column system (comprising the four lectins ConA, JAC, WGA, and UEA I, termed 4L) was applied to glycopeptide enrichment from human tear sample digests. As the main result, a total of 26 N glycosylation sites of 11 N-glycoproteins (LIF, PIGR, IGHA2, IGHA1, AZGP1, LACRT, JCHAIN, PIP, TF, HP, and SERPINA1) was identified in the tear sample pools of healthy individuals.
This result will serve as an important N-glycoprotein reference map for future studies focusing on the ocular surface and will help to unravel the complex regulatory functions of N-glycoproteins in maintaining tear film stability and the ocular defense system.