![Improved MALDI-Matrix for Glycoconjugates Improved MALDI-Matrix for Glycoconjugates](/917589/header_image-1377694616.jpg?t=eyJ3aWR0aCI6ODQ4LCJmaWxlX2V4dGVuc2lvbiI6ImpwZyIsIm9ial9pZCI6OTE3NTg5fQ%3D%3D--1ff603bda8ed00f41bb6c5de907b4761e94193d6)
Improved MALDI-Matrix for Glycoconjugates
Motivation
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) has become a standard method in the field of proteomics by combining fast and reproducible measurements with high mass accuracy. Peptides can be analyzed with high confidence, using standard MALDI-matrices like 2,5-dihydroxybenzoic acid (DHB), and α-cyano-4-hydroxycinnamic acid (CHCA). An upcoming field of application for MALDI-TOF-MS is the analysis of glycoconjugates, like glycans and glycopeptides. Compared to peptides, those glycoconjugates have different requirements on the MALDI-matrix that is used. Here the development of new MALDI-matrices can greatly improve the detection and quantification of glycans and glycopeptides.
![MALDI-TOF-MS spectra of tryptic IgG Fc N-glycopeptides co-crystallized with DHB (Figure A) or Cl-CCA (Figure B) and measured in reflectron-negative ion mode. Profiling of IgG Fc N-glycopeptides was performed after 96-well format cellulose-HILIC purification. Dashed arrows, IgG2 glycopeptides; solid arrows, IgG1 glycopeptides; blue square, N-acetylglucosamine; red triangle, fucose; green circle, mannose; yellow circle, galactose; purple diamond, N-acetylneuraminic acid. *, in-source fragment.](/3368985/original-1718267166.jpg?t=eyJ3aWR0aCI6MjQ2LCJvYmpfaWQiOjMzNjg5ODV9--dba9d6561c191deeba5376dfaf2d9481f34281cc)
Aim of the Project
For MALDI analysis of glycans and glycopeptides the choice of matrix is crucial in minimizing desialylation by mass spectrometric in-source and metastable decay. Here we evaluated the potential of 4-chloro-α-cyanocinnamic acid (Cl-CCA) for MALDI-TOF-MS analysis of labile sialylated tryptic N-glycopeptides and released N- and O-glycans. Similar to 2,5-dihydroxybenzoic acid (DHB), but in contrast to α-cyano-4-hydroxycinnamic acid (CHCA), the Cl-CCA matrix allowed the analysis of sialylated N-glycans, O-glycans and glycopeptides in negative ion mode MALDI-TOF-MS, which clearly demonstrates the potential of this rationally designed matrix.