Enzymic degradation of pectic substances isolated from the inner bark of Ulmus glabra Huds.

Abstract Pectic substances were extracted from inner bark of Ulmus glabra Huds. using water at 100°C. The water extract was fractionated into three polymer fractions using a combination of two different ion exchange chromatography columns (DEAE-Sepharose fast flow and PBE™ 94 (polybuffer exchanger)). The isolated pectic polymer fractions were degraded with pectolyase (endopolygalacturonase and endopectin lyase) after first having been deesterified by pectinesterase. Degradation products were fractionated by gel permeation chromatography (Bio-Gel P-2). The carbohydrate composition of the degraded products were determined by gas chromatography analysis of the trimethylsilyl methylglycoside derivatives and the glycosyl-linkages were established by methylation analysis before and after carboxyl reduction. The degradation products were also subjected to arabinogalactan-Yariv reagent crossed electrophoresis. The results show that the three pectic polymer fractions have similarities in the carbohydrate content and in the type of glycosyl-linkages present; however they react differently towards enzyme degradation and the Yariv reagent.