Carbohydrate structural analysis of wheat flour arabinogalactan protein

The water-extractable arabinogalactan protein (AGP) was isolated from bread wheat flour (Triticum aestivum L variety Cadenza) and the structure of the arabinogalactan (AG) carbohydrate component was studied Oligosaccharides released by hydrolysis of the AG with a range of ACP-specific enzymes were characterised by Matrix Assisted Laser Desorption Ionisation (MALDI)-Time of Flight (ToF)-Mass Spectrometry (MS) MALDI-ToF/ToF high energy collision induced dissociation (CID) and Polysaccharide Analysis by Carbohydrate gel Electrophoresis (PACE) The AG is composed of a beta-(1 -> 3)-D-galactan backbone with beta-(1 -> 6)-D-galactan side chains These side chains are highly variable in length from one to at least 20 Gal residues and are highly substituted with alpha-L-Araf Single GlcA residues are also present at the non-reducing termini of some short beta(1 -> 6)-galactan side chains In addition the beta-(1 -> 6)-galactan side chains are also substituted with beta-L-Arap We propose a polysaccharide structure of the wheat flour AGP that is substantially revised from earlier models (C) 2010 Elsevier Ltd All rights reserved