Enzymatic degradation of pectic substances and cell walls purified from carrot cell cultures

Abstract

The purified pectic substances from carrot ( Daucus carota) cell cultures were depolymerized by purified exo-polygalacturonase and endo-pectate lyase. The degraded pectic fractions were fractionated by gel filtration chromatography, and the degree of polymerization and glycosyl composition determined for each fraction. The results indicate that subfractionated pectic substances contain a homogalacturonan region with a degree of polymerization of ca 70 and neutral glycosyl residues such as side-chains arranged in blocks (‘hairy’ regions) of different M r s. In addition, the endo-pectate lyase released four pectic fragments from isolated cell walls. Based on the analysis of glycosyl composition of each fragment, the pectic substances of carrot cell walls are characterized.