Structural analysis of (methyl-esterified) oligogalacturonides using post-source decay matrix-assisted laser desorption/ionization time-of-flight mass spectrometry

The use of post-source decay matrix-assisted laser desorption/ionization ti me-of-flight mass spectrometry for the structural analysis of ((partly) met hyl-esterified) oligogalacturonides (oligoGalA) is described. The fragmenta tion behavior of purified (un)saturated oligoGalA (degree of polymerization 3-6), methyl-esterified and methylglycosydated oligoGalA was studied, Gene ral fragmentation patterns are described and used for the elucidation of th e positions of methyl esters on partly methyl-esterified oligoGalA, This te chnique now permits the determination of the position of methyl esters or o ther substituents on pectic fragments, helping in understanding the mode of action of pectinolytic enzymes. Copyright (C) 2000 John Wiley & Sons, Ltd.