Pectinases and Pectins

Pectins are complex branched heteropolysaccharides primarily containing an α-(1-4) polygalacturonic acid backbone which can be randomly acetylated and methylated. Three different pectins have been isolated from plant cell walls.
  • Homogalacturonans are composed of the simple α-(1-4) polygalacturonic acid backbone.
  • Substituted homogalacturonans are modifications of this backbone with β-D-xylose branching at C3, or apiofuranose substitutions in the backbone with β-D-Apiosyl-(1,3′)-β-D-Apiose branching.
  • Rhamnogalacturonan I contains alternating α-(1-4) galacturonosyl and α-(1-2) rhamnosyl residues, with primarily oligo α-(1-3) arabinose and oligo β-(1-4) galactose branching.
  • Rhamnogalacturonan II is composed of the simple α-(1-4) polygalacturonic acid backbone with complex branching with composed of up to 11 different monosaccharide types.