Structural Analysis of the Eggplant Xyloglucan by Xyloglucanase

Abstract

A xyloglucan was isolated from the cell-walls of eggplant. This xyloglucan was hydrolyzed with a xyloglucan specific endo-1,4-β-D-glucanase (xyloglucanase) from Penicillium sp. M451. The resulting hydrolyzate was fractionated by Bio-Gel P-2 chromatography. Hexa-, hepta- and octa-saccharide fractions were obtained in a ratio of 35:43:22 as major oligosaccharide fractions. The xyloglucan oligosaccharide fractions were separately subjected to sugar composition and methylation analyses, high-performance anion exchange chromatography with pulsed amperometric detection, and matrix-assisted laser-desorption ionization time of the flight mass spectrometry before and after treatment with an isoprimeverose-producing oligoxyloglucan hydrolase purified from Eupenicillium sp. M9 or with β-D-galactosidase from Bacillus circulans. Hexa-, hepta- and octa-saccharide fractions might consist mainly of XXGG, of XLGG, LXGG and XSGG, and of LSGG and LLGG, respectively. In addition, the oligosaccharide units of xyloglucans from some solanaceous vegetables were comparatively analyzed. Xyloglucans from the cell-walls of sweet pepper, red pepper and tomato belonging to solanaceous vegetables were shown to be composed of hexa-, hepta- and octa-saccharide fractions in a ratio of 40:37:23, 41:34:25, and 45:37:18, respectively.