title: Quantitation of 4-O-methylglucuronic acid from plant cell walls.
abstract: The accuracy of commercial α-D-glucopyranosyl uronic acid (GlcA) as a calibration standard for the determination of the 4-O-methyl-α-D-glucopyranosyl uronic acid (meGlcA) content in plant materials was studied. A batch of meGlcA standard was purified from commercial birch xylan and quantified using nuclear magnetic resonance spectroscopy. Both commercial GlcA and the purified meGlcA were used as standards for the quantitation of meGlcA in Arabidopsis thaliana stems, as well as wood and wheat straw samples using acid methanolysis and gas chromatography (GC). The GlcA standard was partially lactonized during acid methanolysis, thus yielding six glycoside peaks in GC. If all six GlcA-derived peaks were included in the GlcA calibration curve, the calculated meGlcA content was underestimated by 30% compared with that obtained using the purified meGlcA as a standard. The meGlcA content was best estimated by including either the two main GlcA peaks or only peaks corresponding to pyranosides and furanosides of GlcA in the calibration curve.
authors.affiliation: Department of Food and Environmental Sciences, Faculty of Agriculture and Forestry, P.O. Box 27, FI-00014 University of Helsinki, Helsinki, Finland. sun-li.chong@helsinki.fi
authors.forename: Sun-Li
authors.initials: SL
authors.lastname: Chong
authors.forename: Sanna
authors.initials: S
authors.lastname: Koutaniemi
authors.forename: Liisa
authors.initials: L
authors.lastname: Virkki
authors.forename: Henna
authors.initials: H
authors.lastname: Pynnönen
authors.forename: Päivi
authors.initials: P
authors.lastname: Tuomainen
authors.forename: Maija
authors.initials: M
authors.lastname: Tenkanen
mesh_terms: D017360:Arabidopsis / Q000737:chemistry; D002473:Cell Wall / Q000737:chemistry*; D002849:Chromatography, Gas / Q000592:standards; D005965:Glucuronates / Q000032:analysis*; D009682:Magnetic Resonance Spectroscopy; D059828:Plant Cells / Q000737:chemistry*; D018547:Plant Stems / Q000737:chemistry; D012015:Reference Standards; D014934:Wood / Q000737:chemistry
chemical_list: D005965:Glucuronates; C036035:4-O-methylglucuronic acid