The LM6, rat, monoclonal antibody was generated using a neoglycoprotein (arabinoheptaose-BSA) and is a high affinity antibody to (1,5)-α-L-arabinosyl residues found in the arabinan components of certain pectic polymers such as rhamnogalacturonan-I. The LM6 arabinan epitope is widely found in the cell walls of many plants and can also be present in isolated pectin preparations used for commercial purposes. LM6 antibody recognises a linear pentasaccharide in (1,5)-α-L-arabinans and can recognise pectic polysaccharides in several species. It has no cross-reactivity with gum arabic but may recognize arabinogalactan-proteins (AGPs) in some species. In competitive inhibition ELISAs, LM6 antibody binding to (1,5)-α-L-arabinan was inhibited (50%) by 40 ng/mL (1,5)-α-L-arabinopentaose and 19 ng/mL (1,5)-α-L-arabino-hexaose.