Matrix-assisted laser desorption/ionization mass spectrometric analysis of polysulfated-derived oligosaccharides using pyrenemethylguanidine

Abstract

A better understanding of the biological roles of carbohydrates requires the use of tools able to provide efficient and rapid structural information. Unfortunately, highly acidic oligomerssuch as polysulfated oligosaccharides-are very challenging to characterize because of their high polarity, structural diversity, and sulfate lability. These features pose special problems for matrix-assisted laser desorption/ionization mass spectrometric (MALDI-MS) analysis because polysulfated carbohydrates exhibit poor ionization efficiency and usually do not produce any signal. The present report demonstrates how MALDI-MS can be used to derive structural and compositional information from pure and mixed fractions of polysulfated oligosaccharides. Indeed, pyrenemethylguanidine (pmg, a derivatizing agent and ionization efficiency enhancer) was used for the analysis of di-to decasaccharides, carrying from two to nine sulfate groups. The method is applied to various highly sulfated chondroitin and carrageenan oligosaccharides as well as to the analysis of mixtures of compounds. In the mass spectra, the observation of a unique pmg-complexed ladder of peaks in both ionization modes allows an easy and rapid determination of both the number of sulfate groups carried by the analyte and its molecular weight. Moreover, we have developed a software tool for the rapid and automatic structural elucidation of carrageenans based on the mass spectra obtained. (J Am Soc Mass Spectrom 2009, 20, 131-137)

Spectroscopic study of natural and synthetic polysaccharide sulfate structures

“…Spectroscopic (NMR , IR ) and chromatographic (HPLC ) techniques are in general use, but colorimetric and immunologic methods, as well as electrophoresis have also been used in the characterization of carrageenans . Recently the mass spectrometric study of carrageenans has also evoked interest . Synthetic polysaccharide sulfates can be analyzed in a similar fashion as carrageenans.…”

Applications of Mass Spectrometry to Structural Analysis of Marine Oligosaccharides

“…Recently, a report has demonstrated how MALDI-MS can be used to obtain structural and compositional information of CS/DS simply [65]. A new powerful method for the MALDI-MS analysis of polysulfated oligosaccharides was established using pyrenemethylguanidine (PMG) as an effective derivatizing agent and ionization efficiency enhancer.…”

Analysis of Glycosaminoglycans Using Mass Spectrometry

“…Subsequent effort has focused on development of MALDI matrix conditions sufficient to improve the signal strength and eliminate the in-source dissociation problem without the need to add basic peptides. A number of studies have been published toward these ends, with improvements in signal but with the same problems of dissociative losses of sulfate groups during the ionization process (44–48). The ion abundances of CS disaccharides produced by exhaustive enzymatic depolymerization have been used in a quantitative assay in which a linear response is observed over a range of 4–40 pmol of disaccharide on the MALDI target.…”