Separation of eight epimeric 2-aminoaldohexoses as aminohexitol acetates by gas chromatography and analysis of bacterial heteroglycans containing rare 2-aminoaldohexoses and 2-aminouronic acids

Abstract

A method has been developed for the separation of all eight of the possible 2-aminohexitols as alditol acetates derived from 2-aminoaldohexoses by gas chromatography on a capillary column wall coated with Poly A-103 (25 m × 0.25 mm I.D.). For the depolymerization of bacterial polysaccharides containing amino sugars or aminouronic acids, we used methanolysis, which resulted in transglycosylated amino sugar methylglycosides and aminouronic acid methylglycoside methyl esters without appreciable destruction. The latter compounds were converted into amino sugar methylglycosides by reduction with sodium borohydride. This step allows differentiation between amino sugars and aminouronic acids. The usefulness of the method is demonstrated on cell wall polysaccharides of Shigella sonnei, Vibrio parahaemolyticus, Micrococcus lysodeikticus and Methanobacterium thermoautotrophicum containing rare aminouronic acids.