Description_x000D_ General description_x000D_ Polygalacturonic acid is composed of galacturonic acid unit arranged as a long polymer chain. Methyl esters of polygalacturonic acid forms pectin._x000D_ Application_x000D_ Polygalacturonic acid has been used:_x000D_ • in the preabsorption of 2F4 primary antibody solution_x000D_ • as a substrate to determine polygalacturonase activity_x000D_ • in the preparation of oligogalacturonates mixture which is used as a substrate to determine the specificities of different acetylesterases_x000D_ Biochem/physiol Actions_x000D_ In land plants, polygalacturonic acids are major components of cell wall polysaccharides (pectins). Bound polygalacturonase-inhibiting peptides (PGIP) protect pectin from degradation by fungal polygalacturonases.