Determination of the composition of a tetrasaccharide isolated from glycosylated barley β-amylase isozyme using nuclear magnetic resonance

Abstract

In order to determine the composition of a tetrasaccharide obtained from glycosylated barley β-amylase isozyme we applied two-dimensional (2-D) nmr (nuclear magnetic resonance) techniques. COSY (COrrelated SpectroscopY) and TOCSY (TOtally Correlated SpectroscopY) pulse sequences enabled us to achieve an unambiguous assignment of four monosaccharide units by allowing us to follow the shift-correlation map in each monomeric ring. After careful comparison to proton chemical shifts as well as the resonance patterns in literature we have found that there are α-D-G1cNAc, β-D-G1cNAc, α-D-Man and β-D-Man in the tetrasaccharide.