Patterns of methyl and O-acetyl esterification in spinach pectins : new complexity

• Published in: Phytochemistry (Oxford) Vol. 60; no. 1; pp. 67 - 77
• Main Authors: Perrone, Paola, Hewage, Chandralal M., Thomson, Adam R., Bailey, Kevin, Sadler, Ian H., Fry, Stephen C.
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier Ltd 01.05.2002; Elsevier
• Subjects: Acetyl esters; Biochemistry & Molecular Biology; Cell Wall - chemistry; Chenopodiaceae; Chromatography; DQFCOSY; Driselase; Esterification; HMBC; HMQC; Homogalacturonan; Hydrolysis; Life Sciences & Biomedicine; Magnetic Resonance Spectroscopy; Methyl esters; NMR spectroscopy; Oligogalacturonides; Oligosaccharides; Oligosaccharides - analysis; Oligosaccharides - chemistry; Pectic polysaccharides; Pectins - chemistry; Pectins - isolation & purification; Pectins - metabolism; Plant Sciences; Rhamnogalacturonan-I; Science & Technology; Spinach; Spinacia oleracea; Spinacia oleracea - chemistry; Spinacia oleracea - cytology; Spinacia oleracea - metabolism; Acetyl esters; Oligogalacturonides; HMBC; Homogalacturonan; Spinacia oleracea; Oligosaccharides; Chenopodiaceae; DQFCOSY; Driselase; HMQC; Methyl esters; Rhamnogalacturonan-I; Spinach; NMR spectroscopy; Pectic polysaccharides; acetyl esters; Chenopodiacceae; spinach; ACID; homogalacturonan; rhamnogalacturonan-I; pectic polysaccharides; oligosaccharides; NMR EXPERIMENTS; PLANT-CELLS; COMPONENTS; STRUCTURAL-CHARACTERIZATION; SHOOT CELL-WALLS; GALACTURONOYL ESTERS; oligogalacturonides; NMR; spectroscopy; driselase; methyl esters; POLYSACCHARIDE
• ISSN: 0031-9422; 1873-3700
• DOI: 10.1016/S0031-9422(02)00039-0

Driselase-digestion of cell walls from suspension-cultures of spinach ( Spinacia oleracea L.), followed by anion-exchange chromatography, gel-permeation chromatography, preparative paper chromatography and preparative paper electrophoresis, yielded ten uronic acid-containing products in addition to free galacturonic acid (GalA). These included 4- O-methylglucuronic acid, α- l-rhamnopyranosyl-(1→4)- d-glucuronic acid and several oligosaccharides containing GalA residues. The structures were unambiguously determined by a combination of 1- and 2-dimensional NMR spectroscopic techniques. Five of the six homogalacturonan-derived oligosaccharides purified contained 3- O-acetyl-GalA residues; however, methyl-esterified GalA residues occurred adjacent to both 2- O-acetyl-GalA and 3- O-acetyl-GalA residues. An acetylated, rhamnogalacturonan-I-derived oligosaccharide that was purified also contained 3- O-acetyl-GalA residues. Taken together with published data, our findings indicate considerable diversity in the patterns of pectin esterification. The implications for the action of pectin esterases are discussed. Driselase-digestion of primary cell walls of spinach yielded at least 11 uronate-containing compounds, four of which (e.g. [ 2] and [ 9]) were new. The findings increase the known diversity of methyl- and acetyl-esterification sites in pectic polysaccharides.